An increase in blood urea in dogs causes. Creatinine: an insidious assistant. Is the diagnostic and pathogenetic value of creatinine as great as it is usually postulated?

Author: Ph.D. Roman-A. Leonard, practicing veterinarian, head of the Center veterinary nephrology and Urology, President of the Russian Scientific and Practical Association of Veterinary Nephrologists and Urologists (NAVNU)

Key points

1. GFR is the most accurate method for assessing the level renal function in animals with various nephropathies, and ideally, it is on this indicator that the classification of the severity of not only CRF and CKD, but also most kidney diseases in general, should be based.
2. To date, most attempts to calculate GFR in routine veterinary practice are based on the level of azotemia. However, neither the level of creatinine, nor even the level of serum urea are any accurate indicators that can be used to assess the true level of GFR, especially in the initial and final stages of the renal continuum.
3. A normal level of azotemia in an animal is by no means an indication that the patient does not have life-threatening nephropathy. This is primarily due to the fact that an increase in the level of creatinine and blood urea, as a rule, begins to occur only after the GFR is reduced by more than 75%.
4. The calculation of the level of renal function only by creatinine very often leads to an overestimation of GFR, which results, among other things, in the fact that the patient's life-saving nephroprotective therapy is prescribed much later than necessary, or not prescribed at all.
5. Given the wide range of normal serum creatinine levels in animals, when this indicator is found at the upper limit of normal, it can be difficult to determine, especially when primary examination, whether this value is normal for the patient or whether it arose as a result of the progression of any nephropathy.
6. A significant decrease in creatinine levels, especially in severe CKD, does not necessarily indicate an improvement in renal function, but may be due to a decrease in muscle mass and / or anorexia.
7. Hyperazotemia is not necessarily the result of any nephropathy, but may have a pre- or post-renal origin.
8. The significance and consequences of intoxication caused by an increase in the level of creatinine and urea in the blood are still greatly exaggerated.

Introduction

History taking and physical examinations in the early stages of most nephropathies in dogs and cats are not very informative, primarily due to the absence of any clinical manifestations, which is a consequence of the colossal compensatory capabilities of the kidneys. Therefore, the earliest possible laboratory diagnosis of a decrease in renal function is one of the priority and, at the same time, the most difficult tasks of modern veterinary nephrology.

The most reliable information about the excretory capabilities of the kidneys and, consequently, about the functional state of the renal parenchyma as a whole provides a definition of the rate glomerular filtration(GFR) (29).

A steadily declining or low GFR is the most accurate marker of a patient having life-threatening nephropathy or chronic kidney disease (CKD). It is well established that GFR declines steadily in all patients prior to the development of CKD. And CKD itself is necessarily characterized by a decrease in GFR by at least 75% of the norm.

It is not possible to directly measure GFR. The most accurate information about it is given by the definition of the clearance of a substance that is not synthesized in the body, physiologically neutral, freely filtered in the glomeruli and not secreted, not reabsorbed and not metabolized in the tubules. Since the amount of this substance injected intravenously into the body and filtered unchanged in the glomeruli is equivalent to the amount excreted in the urine, this allows you to accurately determine the GFR for the kidneys as a whole. Today, the clearance of the fructose polysaccharide inulin is used as the "gold standard" for evaluating GFR.

However, the determination of GFR by inulin clearance in veterinary medicine has a number of significant limitations, both related to technical difficulties and due to very high cost conducting the test itself.

Currently, in routine practice, an attempt to determine the GFR in a patient is almost always made by measuring the level of creatinine in the blood serum. It is also the basis for the most widely used CKD grade classification (IRIS) in veterinary medicine. But this is due not so much to the diagnostic value of creatinine as an indicator of the level of GFR, but to the relative simplicity, accessibility and low cost of determining this laboratory indicator.

Establishing the level of creatininemia - a widely used method of laboratory diagnostics (often used in general as the only test for detecting CKD, or even any nephropathy in animals) - gives a very approximate idea not only of GFR, but also of the stage of nephropathy in general. In addition, the determination of the level of creatinine has a number of very serious limitations in verifying the severity of kidney disease, especially in the early and late stages of the renal continuum. And its normal boundaries in the blood serum do not always mean that the animal does not have life-threatening nephropathy. That is why the 1st degree of CKD, according to the IRIS classification (Table 1), is non-azotemic.

Table 1. Classification of degrees of CKD based on the concentration of creatinine in the blood serum of dogs and cats, according to the site www.iris-kidney.com

It should also be noted that the properties of creatinine and urea as the leading uremic toxins, with which most of the clinical manifestations of CKD are allegedly associated, are significantly exaggerated. Currently, both pathophysiologists and nephrologists agree that an increase in the level of azotemia, although it can have a certain adverse effect on the functional state of the body, is still not the leading factor of intoxication that initiates a number of various clinical manifestations in CKD. .

Creatinine

Creatinine (like urea) is one of the end products of nitrogen metabolism, normally excreted mainly in the urine. It is formed from the protein creatine, which serves as an energy source for skeletal muscles. In them, creatine is deposited in the form of a compound called creatine phosphate (creatine phosphoric acid). With the contraction of muscle fibers, creatine phosphate gives up its energy, and itself breaks down to end products - creatinine, water and phosphorus residues.

The newly formed creatinine freely passes through the filtration barrier of the glomeruli, but, in addition, it is also secreted into the lumen of the proximal tubules from the peritubular microcapillary network. Therefore, the amount of creatinine entering the urine and excreted from the body in healthy animals is the sum of filtered and secreted.

However, in dogs and cats with CKD, creatinine begins to be intensively released into the intestinal lumen and then, due to the abundant growth of saprophytic bacterial flora (which is common in CKD patients), it is destroyed there. As a result, in patients with a pronounced decrease in kidney function, the elimination of creatinine from the body by more than 2/3 can occur through the gastrointestinal tract (which is one of the many reasons that complicate the assessment of the level of renal function, calculated only on this indicator).

Since creatinine is formed mainly as a result of creatine biotransformation in skeletal muscles, the volume of its synthesis is directly proportional to the total muscle mass and the intensity of metabolic processes occurring in it. Therefore, the average daily volume of creatinine formation is higher in young animals than in old ones, as well as in those leading an active lifestyle than in those suffering from physical inactivity.

Serum creatinine levels can vary considerably between cats and especially between breeds of dogs (normal values ​​are in the range greater than 100 mmol/l). Cachexia of any origin, as well as low-protein nutrition, or even more so anorexia, can also lead to a decrease in the level of creatininemia. The high content of meat ingredients (primarily thermally processed) in the feed consumed by animals, on the contrary, can lead to an increase in the level of azotemia, since part of the creatine is converted into creatinine during the preparation of feed.

And the level of urea in the blood in general directly depends on the amount of protein consumed and can change several times during the day. Therefore, animals on a low protein diet are likely to have lower levels of azotemia than would be expected from other laboratory and imaging data.

Situations or conditions that can significantly reduce the diagnostic value of determining the level of creatinine can also include the following:

• extreme values ​​of age and very small or, conversely, large intraspecific body mass;
• obesity;
• severe deficiency of plastic and / or energy substances in the body;
• low protein diet;
• rapidly, as for example in acute glomerulo- or tubulointerstitial nephritis, changing kidney function.

Since the level of azotemia, which is within the normal range, does not always indicate that the patient does not have life-threatening kidney disease, it is necessary to evaluate kidney function by all other available non-invasive methods before prescribing nephrotoxic drugs (urine analysis can often "tell" about kidney function much more than blood tests) and carefully weigh the need for it.

Of the theoretical premises due to which creatinine is widely used to diagnose renal failure, only two can be distinguished: creatinine clearance is almost identical to the GFR calculated according to the "gold standard" for this indicator, and the rate of creatinine excretion in each individual animal is approximately constant over time. But here there is a very significant "but". Fundamental physiology suggests that this is true only for patients whose GFR is reduced by no more than 25%, i.e. in practically healthy animals, or, in any case, in those that completely lack any clinical signs of nephropathy (it is worth recalling that both animals and humans can feel great with only one healthy kidney, and in this case GFR is, of course, reduced by at least 50%) (37). In addition, the rate of creatinine excretion, which is relatively constant in humans, has marked intraspecies differences in small domestic animals due to the wide variety of breeds of cats and dogs, whose weight can vary by more than 100 times. Therefore, oddly enough, the decisive factors in choosing serum creatinine as a marker of the level of renal function were the following:

• the availability of its definition from an economic point of view (as well as the fact that the measurements themselves are easily reproducible in almost any clinical laboratory);
• the diagnosis of various nephropathies in animals is made mainly at the clinical stage of the renal continuum (i.e. at the stage of CKD), when the GFR is reduced by more than 75% and the level of azotemia really begins to increase rapidly.

And only because of this, despite the fact that the level of blood serum creatine gives a very distant idea of ​​GFR (and most often does not give any at all) and, consequently, of renal function in general, it is he (as well as urea, which has even less diagnostic value) ) is most commonly used in routine practice to diagnose nephropathies and assess their severity in small pets.

Factors leading to errors in calculating GFR from creatininemia

In human medicine, there are more than 20 predictive formulas for calculating GFR from creatinine in adults and children, with varying degrees of bias and precision relative to the results of its measurements by methods referred to as the "gold standard". The reliability, and hence the clinical value, of most of these predictive formulas was found to be very low (i.e., their calculations systematically resulted in significant overestimation or underestimation of GFR). But even those formulas that showed a relatively high degree of approximation to true GFR (for example, the Cockcroft-Gault formula (Cockcroft-Gault), formulas from the MDRD study, and the CKD-EPI equation (Chronic Kidney Disease Epidemiology Collaboration equation) belonging to the same authors ( 41)), for a variety of reasons, cannot be directly installed on animals.

• Creatinine production in cats, and especially in dogs, varies greatly by breed, sex, age, and level of physical activity. So, for example, the normal value of the creatinine level for beagles and greyhounds (up to 220 mmol / l) corresponds to the third, penultimate, severity of CKD according to the classificationIRIS.
  
• Almost all methods for assessing GFR, with the exception of some based, for example, on the determination of inulin clearance (the so-called "gold standard"), give a very biased estimate of the level of renal function. It can be especially pronounced when trying to measure it using serum creatinine. Such a definition of GFR leads to its systematic overestimation, as a result of which animals requiring nephroprotective and diuretic therapy do not receive it.

Factors that reduce the value of measuring serum creatinine as an index for evaluating GFR

The main limitations of using serum creatinine concentration as a laboratory indicator by which the degree of decline in renal function can be assessed include the following.

1. Very wide range of normal serum concentrations in animals. This circumstance often allows the patient to increase its level by more than 2-3 times before it reaches the upper limit of the norm (i.e., nephropathy progresses intensively, but due to the initially low level of creatinemia, it can only be diagnosed by other methods).
2. Due to the large functional reserve of the kidneys, the concentration of creatinine may not go beyond normal values ​​in cases where most of their parenchyma is in a state of partial and / or complete destruction (scheme 1 and 2). This is also true in the early stages of renal dysfunction in the range between hyperfiltration and early hypofiltration, when there is no proportional relationship between creatinine levels and true GFR values. The situation is aggravated by compensatory hyperfiltration of creatinine into the urine or into the intestinal lumen, which occurs in most chronic nephropathies, especially at the preclinical or, respectively, clinical stages of the renal continuum.
3. Extremely low sensitivity to changes in kidney function, especially in the early and late stages of the course of chronic nephropathy (the relative exception, perhaps, is only a small interval of the renal continuum, which can be attributed to II-III degrees of CKD according to the IRIS classification (Table 1). In addition, creatinine levels are very inertial, and this does not allow rapid assessment of changes in GFR with deterioration or improvement in renal functions resulting from the development of the disease or nephroprotective therapy.The latter is especially important in acute nephropathies, when creatinine does not accurately reflect the real picture of renal parenchyma damage until until some stabilization of the patient's condition is achieved, which most often occurs 48-72 hours after the onset of the disease (for example, acute glomerulonephritis). Apia is needed as soon as possible after the onset of the disease.
4. Dependence on the change in lean (but not total) body weight of the patient (which, for example, in cachexia, which usually develops in animals with CKD, can create the illusion of improving renal excretory functions). Creatinine synthesis in animals with severe CKD is reduced not only due to a decrease in muscle mass, but also, especially in cats, due to a deficiency of plastic substances (primarily arginine, glycine and methionine) caused by anorexia.
5. Initially, not very high, being in the lower third of the range of normal values, the concentration of creatinine in the blood serum in patients with small muscle mass and physical inactivity, and, on the contrary, initially high in patients with a large mass and leading an active lifestyle. Thus, it can be very difficult to assess how significant the increase in creatinine level was in an individual patient, not only because of the wide range of normal values, but also because of the lack of information (which is most often the case at initial presentation) about the starting point from which this growth has begun.
6. An increase in tubular secretion (up to 30% of the total volume) and the generation of creatinine, as well as its extrarenal excretion in many nephropathies. So, for example, in patients with a pronounced decrease in kidney function up to 2/3 of the total daily excretion of creatinine, it can occur due to its extrarenal elimination (for example, through the gastrointestinal tract, where creatinine is destroyed by saprophytic microflora and / or is excreted with feces).
7. Some drugs (eg, cimetidine, trimethoprim) reduce tubular creatinine secretion by increasing serum creatinine concentration (on the other hand, the administration of these medicines sometimes used to more accurately determine the patient's true creatinine level, reduced as a result of increased tubular secretion) (17, 30).
8. A number of exogenous chemical substances(eg, cephalosporins) can be detected in serum as creatinine in laboratory tests. Also, in patients with ketoacidosis, acetoacetic acid can "mask" as creatinine, creating a false impression of an increase in its content in the blood.
9. Use by laboratories various methods determination of creatinine (there is also insufficient attention to the calibration of biochemical analyzers). This leads to the fact that in the same patient and at the same time, its values ​​can vary significantly.
10. In puppies and kittens, an additional complication in determining the level of renal function by creatinine is intensive muscle growth and maturation.

Measurement of endogenous creatinine clearance as a marker of renal function in a patient, from a theoretical point of view, can provide more accurate information. But in practice, the calculation of GFR and this indicator is not always equivalent to the calculation of the "gold standard". In addition, 24-hour measurement of creatinine clearance is daunting task, since, among other things, it requires the collection of a daily volume of urine, which in itself lays a large percentage of errors. And the creatinine clearance itself varies significantly from day to day, leading to serious inconsistencies even with the correct daily urine collection. It should also be remembered that the more severe the degree of CKD, the more creatinine is eliminated from the body not only with urine, but also through the gastrointestinal tract.

In addition, there are no data on normal creatinine levels in cats over 10-15 years of age and in dogs over 7-9 years of age. While in elderly patients, due to purely physiological processes, as "aging of the kidneys" in particular, and of the whole organism as a whole, the level of creatininemia often does not correlate with the data of other non-invasive and invasive methods diagnostics. So, for example, in animals with secondary contracted kidney, severe hypertension and severe nephritic syndrome, azotemia may be within the normal range or even be below it.

The stages of the course of chronic nephropathies and the level of creatininemia characteristic of them are shown in Table 2

It should also be taken into account that urea is not used as a variable in predictive formulas for determining GFR, and none of the existing classifications of the degrees of CRF or CKD, either in animals or in humans, has been built at its level. This indicates an even lower diagnostic value of this biochemical indicator, even in comparison with creatinine.

Creatinine and urea as uremic toxins

For a long time it was believed that creatinine and urea are not only markers of renal failure, but also cause most of its clinical manifestations. However, these views on the pathogenesis of CKD and CKD are currently being revised. First of all, it is not without interest that dogs and cats with elevated levels of creatinine and urea may not have any clinical manifestations. And long-term exogenous administration of large doses of these substances to healthy animals does not lead to the appearance of signs of CKD in them.

Today, many authors are inclined to believe that the most significant factors of the so-called. Uremic intoxication (i.e., a symptom complex that occurs in the later stages of the renal continuum) is primarily a violation of the calcium-phosphorus balance in the body and hyperparathyroidism developing against its background. And it is the parathyroid hormone, which has receptors not only of the first type on osteoblasts, but also of the second type in many other organs and tissues, that plays a key role in the development of a number of complications of CKD, at least in the early and middle stages of its course. At the final stage of CKD (uremic, terminal, or IV according to the IRIS classification), the condition is repeatedly aggravated by a violation acid-base balance in the body (acidosis, for example). Against this background, the accumulation of end products of nitrogen metabolism, although, perhaps, has a certain toxic effect, but is unlikely to prevail.

Pre- and postrenal azotemia

In the development of azotemia, the kidneys are far from always “guilty” (although sooner or later, in the absence of adequate therapeutic measures, this paired organ is drawn into the pathogenesis of any pathology characterized by hyperazotemia).

Prerenal azotemia (hypovolemic, hypotensive, etc.) usually has vivid clinical manifestations or, in any case, can be theoretically predicted (for example, its development can be assumed before a long surgical operation or after massive blood loss). With postrenal azotemia, things are somewhat more complicated. Of course, acute urinary retention resulting from urethral obstruction is also not difficult to diagnose. But here are the breaks Bladder and, especially, the ureters may go unnoticed and require, in particular, imaging diagnostic methods. Moreover, the first clinical signs of CRF at the same time begin to appear only when the creatinine level becomes higher than 440-600 mmol / l. The latter, by the way, is additional evidence that the significance of azotemia in the pathogenesis of the so-called. uremic intoxication and CKD are greatly exaggerated.

Conclusion

Serum creatinine is now very widely used to diagnose various nephropathies, as well as to classify the stages of CKD in dogs and cats. However, in the vast majority of cases, this indicator is not an exact equivalent of GFR (neither by itself, even in the case of calculating its daily clearance, nor as a variable in predictive formulas) and, therefore, cannot reflect the true level of renal function in general. Therefore, in order to identify nephropathies and assess the severity of their course, it is necessary to resort to the widest possible range of non-invasive, and, if necessary, invasive, research methods (as well as to statistical information on the prevalence of certain nephropathies in a particular region, obtained as a result of processing data from histomorphological studies autopsy material) in order to diagnose the pathology at the earliest possible stage, i.e. when its effective etiological and/or pathogenetic treatment is still possible and there is a chance to delay the appearance of the first clinical signs of CKD for years.

A gross medical error can be attributed to a situation in which nephropathy is diagnosed only when the patient's level of azotemia begins to increase (especially since the GFR calculated from the level of creatinine and / or urea, and therefore the level of renal function as a whole, is systematically and significantly overestimated) . This is due to the fact that at the azotemic stage of the renal continuum, most of the formed elements and stroma of the kidneys are already in a state of complete or partial destruction (sclerosis, etc.). And this approach allows starting the treatment of kidney diseases only when only symptomatic and / or replacement therapy, and the quality of life of both the patient and its owners is rapidly and steadily declining despite the ongoing therapeutic measures.

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Footnotes

GFR determinations based on the clearance of such exogenous radioactive labels as 125 I-iothalamate and 99m Tc-DTPA, although also highly accurate methods for measuring this indicator, are currently even less accessible than the inulin test. And the determination of GFR by plasma clearances of substances such as iohexol and 51 Cr-EDTA, among other things, requires the calculation of the exact surface area of ​​the patient's body, which is far from always possible in veterinary medicine.

www.iris-kidney.com

From English. precision — precision.

Various human medicine clinical trials compared renal function using a predictive formula with serum creatinine as one of the variables, and then compared these results in the same patients with GFR determined using gold standard methods. ".

Modification of Diet in Renal Disease Study (Levey AS et al., 1999).

Today, parathyroid hormone also plays a leading role in the development of such a complication of CKD as myocardiopathy (38,39).

MAIN PROVISIONS

• Chronic renal failure (CRF) is the most commonly diagnosed kidney disease in dogs.
• Clinical signs of the disease appear only after at least 67% of the renal parenchyma ceases to function.
• Diagnosis of early stages of impaired renal function allows timely use of protection techniques, incl. transfer the animal to a special diet and prescribe appropriate drug therapy in order to slow down the development of further lesions of these organs, speed up recovery and improve the quality of life of the animal.
• The plasma clearance test for exogenous creatinine can be used in routine veterinary practice.

Chronic renal failure (CRF) is the most commonly diagnosed kidney disease in dogs. It develops as a result of the progressive and irreversible loss of functioning nephrons. Clinical signs of renal failure begin to appear when 67-75% of the renal parenchyma ceases to function. Polyuria and polydipsia are usually the first signs of kidney disease, but they are often overlooked for a long time. It is generally accepted that a decrease in the specific gravity of urine and azotemia (i.e., the excess of the concentration of creatinine and / or urea of ​​the permissible norm) occurs only after the failure of at least 67% and 75% of the renal parenchyma, respectively (Fig. 1). Therefore, CKD is usually diagnosed at a relatively late stage of kidney disease. Over the past 20 years, significant progress has been made in diet therapy and drug treatment of chronic renal failure, but the problem of its early diagnosis is still relevant. Establishing a violation of kidney function at the very beginning of the disease makes it possible to use means to protect these organs from further damage, incl. prescribe a special diet or drug therapy. This will slow down the development of kidney disease, shorten the recovery period and improve the quality of life of sick animals. This publication describes a number of strategic approaches to the detection of renal dysfunction in dogs with subclinical CKD.

Figure 1. The consequences of kidney disease and the development of uremic syndrome with it.

Informing and educating pet owners, identifying risk factors

CRF is frequently reported in dogs. Therefore, every dog ​​owner should be informed about chronic renal failure, its prevention, manifestations of diagnostic significance, as well as factors contributing to the development of this pathology. Particular attention should be paid to dog breeds that show a predisposition to kidney disease. It is important to reassure breeders that kidney problems can occur even in clinically healthy dogs. Owners should be advised to monitor their pets on a regular basis so that they can judge whether the disease is progressing or not and seek timely help from specialists for further examinations. Well-informed breeders can provide very important information about their pets' water and food intake, as well as changes in animal body weight.

Risk factors associated with the development of CKD in dogs are poorly understood, but appear to be this pathology most often manifested in adult animals of this species: the age of 45% of dogs with CRF is more than 10 years old. This does not mean that any adult dog can get sick, but suggests the need to determine the concentration of creatinine in the blood plasma and specific gravity of urine (URG) in animals as the most important indicators of the health of aging animals. Hereditary nephropathies have been reported in some dog breeds (Table 1), although their incidence remains unknown. These hereditary diseases can develop in puppies, young, adult and aging dogs. If it is suspected that dogs of these breeds have impaired renal function, it is necessary to collect anamnestic data on whether such a disease has occurred in animals of this line (in parents, littermates, other relatives). CKD can cause different reasons, and setting any of these etiological factors(for example, according to the anamnestic data that the animal had been ill with piroplasmosis, hypertension, etc. in the past) (Fig. 2) should serve as a reason for studying the kidneys.

Figure 2. Causes of Acquired Chronic Renal Failure

Regular assessment of animal water intake, diuresis, appetite and body weight

Polyuria and polydipsia resulting from loss of the ability to concentrate urine are not specific to CKD but are considered early clinical manifestations. It can be difficult for owners to determine how much urine their dogs produce. To accurately determine this indicator, the animal is hospitalized and placed for a day in a metabolic chamber (usually this is used for experimental purposes, and not for routine diagnostic examinations). Before being placed in the chamber and before being released from it, the animal is made to perform the act of urination. An adult dog excretes approximately 20-40 ml/kg of body weight of urine during the day (in puppies this figure is higher).

Assessing a dog's water intake is much easier, especially when the animal's access to water is controlled. Owners of dogs at high risk for CRF are advised to conduct an annual control determination of their pets' water intake. This indicator is considered normal if it does not exceed 100 ml / kg of body weight. The volume of water drunk daily by animals is variable, as it depends on a number of factors, incl. physical activity, air temperature, type of diet, etc. Therefore, the measurement of the amount of water consumed by the dog is carried out for 3-4 days in a row. To avoid subjectivity in determining this indicator, the dog owner needs to weigh a bowl of water 2 times a day (with an interval of 24 hours).

Some decrease in appetite and body weight, although not specific to CRF, often accompanies this pathology. Daily feed intake is estimated by weighing it at each giving to the animal. When changing the diet, the animal's appetite may change depending on how new food attractive to him. Weighing animals is less subjective, but should be done regularly and on the same scales.

Indirect assessment of kidney function based on the results of repeated studies of blood plasma and urine

This article discusses the possibility of diagnosing CRF only in those animals in which this pathology is asymptomatic or manifests itself with mild clinical signs. The best markers of kidney function in this situation are creatinine and urine specific gravity.

Plasma creatinine concentration

Creatinine is constantly produced in the muscles as a result of creatine metabolism. It is excreted from the body only in the urine, being completely filtered in the kidneys through the glomeruli and only slightly secreted in the renal tubules. Plasma creatinine concentration is considered the best indirect indicator of kidney function, although many factors influence the accuracy of its determination.

In this regard, it is impossible to discount the influence of various factors acting before taking the analysis and during its implementation. Blood samples for its implementation should be taken from animals on an empty stomach (a 12-hour overnight fast is enough). Most foods contain some creatinine, so after taking them, dogs can experience an increase in its blood concentration above the acceptable level, which causes non-specific test readings. Exercise stress does not lead to a significant change in the concentration of creatinine in the blood plasma in dogs. Plasma creatinine concentration is better determined by the enzymatic method, and not by the Jaffe method, since the indications of the latter are influenced by an increased (> 50 μmol / l) concentration of bilirubin in the blood.

Figure 3. Dependence of plasma creatinine concentration and glomerular filtration rate (GFR) is graphically expressed by a curved line. This indicates an early stage of renal dysfunction, manifested by a decrease in GFR and a corresponding slight change in plasma creatinine concentration. In contrast, dogs with severe renal insufficiency show significant fluctuations in plasma creatinine levels, with relatively limited fluctuations in GFR.

It is believed that an increase in the concentration of creatinine in the blood plasma indicates a decrease in the functional state of the kidneys. The dependence of this indicator and GFR is graphically depicted by a curve (Fig. 3). Meanwhile, the concentration of creatinine in blood plasma depends on a combination of factors such as the formation, distribution and excretion of creatinine from the body. This means that this indicator can be increased in dogs with developed muscles or suffering from dehydration. In animals with renal insufficiency, endogenous creatinine production is reduced (2). As a consequence, elevated plasma creatinine does not necessarily correlate with GFR, as creatinine production can also be reduced as a result of decreased muscle mass. Dehydration can lead to a decrease in the volume of distribution of creatinine, which depends on the total body water supply. However, dehydration usually occurs only in the later stages of CKD.

A once determined concentration of creatinine in the patient's blood plasma is usually compared with the maximum allowable value of this indicator. If the concentration of creatinine in the blood of the animal is higher than the latter, then the presence of kidney pathology is assumed, and if it is below the permissible level, then the animal is considered healthy. But in some situations this approach is wrong. Literature data on the permissible value of such an indicator are very variable (Fig. 4), which is partly due to the characteristics of the populations of dogs in which blood testing was performed, its dependence on age, breed, and a number of other factors. In dogs of different breeds and animals of different ages, the normal concentration of creatinine in the blood is not the same. For example, it is higher in adult dogs compared to puppies, as well as in breeds of dogs with more developed muscles. Therefore, one should be very careful in interpreting a slight excess of this indicator of the norm. Impaired renal function can also occur in cases where the concentration of creatinine in the blood plasma remains within the normal range.

Figure 4. Various allowable values ​​for canine plasma creatinine levels (according to veterinary guidelines or from Reflotron, Kodak and Vettest analyzers). There are significant discrepancies between data obtained from different sources, which may be due to differences in control samples or methods of analysis

However, even the results of a single determination of the concentration of creatinine in blood plasma provides valuable diagnostic information, on the basis of which the International Renal Interest Society has recently proposed a classification stages of chronic renal failure in dogs and cats, based on the value of this indicator (table 2).

Significantly more accurate readings are obtained by serially determining the concentration of creatinine in the blood plasma in a dog for some time (for example, one year). At the same time, it is important to standardize the conditions for testing in order to to avoid the influence of factors that complicate the interpretation of the results. So, for example, blood should be taken from the dog on an empty stomach each time, the same testing method should be used, and the body condition of the animal should not change throughout the entire study period. Blood plasma samples are stored until the study is frozen (at a stable temperature not exceeding -20°C). When it is time to study the next blood plasma sample, the one taken the previous time is thawed and examined simultaneously with the last one. This establishes a "critical change" in the measurable index, which is the minimum difference between two consecutive levels of plasma creatinine concentration and reflects biologically significant changes in kidney function in healthy dogs. dl).

When a dog suddenly develops significant changes in the concentration of creatinine in the blood plasma, their relationship with the state of health of the animal is checked by a repeated study, which makes it possible to exclude diagnostic errors (Fig. 5).

Figure 5. Variation in plasma creatinine due to analytical errors. From the blood plasma samples of the dogs, they were blinded twice in the same laboratory. Very large discrepancies in the results of testing one sample were obtained - 0.7 (62 µmol/l) and 2.1 mg/dl (186 µmol/l). These observations indicate the need to re-examine serum samples in cases of unexpectedly high or low readings compared to previous plasma results from the same animal.

Specific Gravity of Urine (SPM)

TPM is the ratio of the mass of a certain volume of urine to the mass of the same volume of pure water at the same temperature. UPM is determined using a refractometer. Changes can occur already at the initial stage of renal failure. However, TMR - highly variable even in healthy dogs - can change with the animal's water intake and diet. The TFR also varies from day to day, from one sample to another. When the body is normally hydrated, the BMR usually ranges from 1.015 to 1.045, but can decrease to 1.001 or increase to 1.075. If the TMR rises above 1.030, the dog begins active resorption of water from the renal tubules and collecting ducts of the kidneys. With a decrease in the UPM below 1.008, the animal begins the resorption of salts from the filtrate located in the renal tubules. In both cases, the kidneys compensate for these changes. When determining the TMR, the degree of hydration of the animal's body is taken into account: too low TMR (<1,030) на фоне обезвоживания организма указывает на первичную дисфункцию почек или другие причины, повлекшие за собой снижение концентрирования мочи. Однако возможна и такая ситуация, когда при обезвоживании организма у собаки с субклиническим нарушением функции почек УПМ оказывается выше 1.030. Из-за вариабельности УПМ однократно выявленные изменения этого показателя не обязательно указывают на полиурию, но критериями последней служит персистентное значение УПМ в пределах от 1,008 до 1,029. Сопутствующая азотемия дает больше оснований подозревать наличие заболевания почек, но не позволяет поставить окончательный диагноз.

Other indicators

Plasma urea (or "blood urea nitrogen") concentration is also important in the diagnosis of clinical CKD. A number of researchers believe that this indicator correlates better with the clinical signs of the latter than the concentration of creatinine in blood plasma. However, plasma creatinine seems to be a better reflection of GFR decline than blood urea, due to the presence of many extrarenal factors that can affect the value of the latter indicator. These factors include feeding and starvation, metabolic activity of the liver, dehydration, etc. Therefore, the concentration of creatinine in the blood plasma is more important for diagnosing the early stage of impaired renal function and the latter in subclinical cases.

Electrolyte disturbances (hyperphosphatemia, hypokalemia, hypocalcemia) are noted during a period of significant impairment of kidney function, but they are absent in the early subclinical stages.

Proteinuria can develop at any stage of CRF. and its intensity is largely determined by the etiology of the disease. When proteinuria is detected, additional studies are necessary to establish the cause of the disease. However, in many animals with CRF, proteinuria is mild.

Testing the ability of the kidneys to concentrate urine

With chronic renal failure, the ability of the kidneys to concentrate urine decreases, but other factors also influence the value of the ULR, incl. treatment with diuretics and glucocorticoids, glucosuria, diabetes insipidus, imbalance of basic electrolytes. The test, based on the restriction of the dog in water, allows you to evaluate the concentrating activity of the kidneys in polyuria or polydipsia without determining their causes. It should not be used to examine dogs suffering from dehydration and/or azotemia, as its administration in such cases is associated with the risk of harm to the health of animals and since dehydration in patients with low TLR is itself evidence of the loss of the ability of the kidneys to concentrate urine. This test can be carried out in two versions (table 4). However, its sensitivity in the diagnosis of early stage CKD has not been documented.

Direct method for determining GFR

GFR is currently considered the best direct indicator of kidney function. Over the past 30 years, many new methods for determining this indicator have been proposed and tested, based on determining the clearance of certain markers in urine and blood plasma from the corresponding marker.

Urine and plasma clearance, application restrictions

Determination of inulin clearance in urine is considered a reference method for assessing GFR. The calculation is simple, and for its implementation it is necessary to know only three indicators: the volume of urine excreted by the animals for a certain period, as well as the concentration of the marker in the urine and blood plasma. Despite providing valuable diagnostic information, urine clearance tests are rarely used in veterinary practice, because they are time consuming and labor intensive. In addition, it is necessary to collect urine at a certain time, and in the process of frequent catheterization, the risk of injury and infection of the urinary tract of animals increases. While the dog is in the metabolic chamber, urine collection can be limited to 24 hours, but there is a need for repeated washings of the chamber to maximize the collection of the marker, the remains of which in subsequent tests can cause an incorrect determination of clearance.

For these reasons, tests designed to determine plasma clearance (especially those involving a single intravenous administration marker) are considered an alternative to appropriate urinalysis in cases where urinary marker excretion is negligible. The main advantage of the test, which determines GFR by its clearance from blood plasma after a single intravenous injection of a marker, is that only one blood sample is required to obtain a result. Radiopaque agents (eg, iohexol and iothalamate), inulin, various radioactively labeled substrates, and creatinine are used as markers. These tests have a number of limitations. For example, radioactively labeled nucleotides cannot be used in routine diagnostic practice due to safety and legal restrictions. Detection of most of the available markers is difficult, costly, or simply out of the reach of the conventional veterinary practice. The iohexol test requires a rather large volume of blood plasma (3-4 ml, i.e. approximately 8 ml of blood), which is too much for dogs small breeds. This marker is detected by a specific fluorescent glow in x-rays. Finally, when determining plasma clearance, which is the ratio of the dose of the marker administered to the animal and the area under the curve of its plasma concentration (AUC) over time, complex calculations are required (data modeling using exponential equations), which discourages veterinary practitioners from its application.

Plasma clearance test for exogenous creatinine (ECPEC)

TCPEC was developed recently and tested on dogs in comparison with known methods for assessing GFR (tests to determine the clearance of inulin and endogenous creatinine in the urine, blood plasma from iothalamate). Plasma and urine clearance from creatinine is consistent with GFR in dogs. With its help, it is possible to diagnose subclinical kidney dysfunction in this animal species. The main advantage of TCPEC is the ability to determine the baseline plasma creatinine concentration, which provides a direct estimate of GFR, regardless of the volume of distribution and endogenous production of creatinine.

The main stages of the TCPEC

> Determination of fasting baseline (initial) plasma creatinine concentration before the test.
> Intravenous administration of a certain amount of creatinine.
> Determination of plasma creatinine concentration.

Calculation of blood plasma clearance.

The main advantages of TKPEC:

> The test can be performed in normal veterinary practice because it is simple, easy to perform (intravenous marker injection and blood sampling) and time-consuming.
> Only 1 ml of blood is needed to obtain a result, which makes it possible, if necessary, to re-sample blood from small breed dogs or puppies, and, in addition, limits the number of manipulations performed on the animal.
> Creatinine is safe: increasing its concentration in the blood plasma of sufferers CKD in dogs after intravenous administration up to 8000 µmol / l (90 mg / dl) does not lead to unwanted side effects.
> There is no need to resort to the services of specialized laboratories, because Plasma creatinine concentration can be quickly determined using a conventional veterinary chemistry analyzer.
> The results of the test are received immediately after it is set.
> Determination of creatinine clearance does not require complicated calculations
> TCPEC does not require large financial outlays.

There are no commercial preparations of creatinine - they have to be prepared independently, although preparations are underway for the production of this reagent.
- The last blood sample must be taken from dogs for examination no later than 6 hours after administration of creatinine. Therefore, the dog has to be hospitalized for the whole day during the test.
- Limits of normal GFR values ​​for dogs have not been definitively defined. Currently, the maximum allowable value of this indicator is 1.5 ml / kg / min, but the results of further studies may make their own adjustments.

Conclusion

The fight against CRF is one of the main problems in ensuring the health of small domestic animals. Currently, its early diagnosis is difficult, because in the initial stages of chronic renal failure is asymptomatic. However, a number of steps can be taken in this direction. useful action: informing pet owners about this pathology, regular examination of their pets, including determination of changes in TLR and concentration of creatinine in their blood plasma over time, as well as assessment of GFR (if necessary). The main hope is that early diagnosis of CRF will help to start treating a sick animal in a timely manner and transfer it to a special diet, which will both prolong the patient's life and improve its quality.

Herve P. Lefebvre
Herve P. Lefebvre, DVM, PhD, Dipl ECVPT, Professor of Physiology
Jean-Pierre Bron
Jean-Pierre Braun, DVM, PhD, Dipl ECVCP, Professor of Biochemistry, Physiology and Therapy, Department of Pathophysiology and Experimental Toxicology, National Veterinary School in Toulouse, France
A. David J. Watson
A. David J. Watson, BVSc, PhD, FRCVS, FAAVPT, MACVSc, Dipl ECVPT,
Associate Professor of Veterinary Medicine, Department of Veterinary Sciences, University of Sydney, Australia

This topic is a tribute to the need, because more than once I have been asked to collect all the important information on this problem in one place in order to help confused owners to act most effectively when a dog is diagnosed with a terrible diagnosis - CRF (Chronic Kidney Failure)

What is kidney failure in Shar Pei

kidney failure- a pathological condition in which the kidneys partially or completely lose their functions. As a result, the biochemical composition is disturbed internal environment organism. Non-volatile acids and nitrogenous metabolic products are retained in the body, an imbalance of water and salts occurs, beriberi water soluble vitamins, conditions arise for the development of insufficiency of other organs - the heart, pancreas, liver, ulceration of the mucous membranes occurs, primarily the gastrointestinal tract, which leads to multiple stomach ulcers, bleeding gums, etc. A steady decrease in kidney function by 70% or more leads to uremia - self-poisoning of the body with a fatal outcome.

Distinguish between acute and chronic renal failure. Acute renal failure (ARF) is characterized by a rapid onset, a relatively short cyclic course, and often a complete regression. Severe acute renal failure can be irreversible and then inevitably becomes chronic. Chronic renal failure (CRF) usually begins imperceptibly, develops gradually and has a progressive course; in the final stage of chronic renal failure, blood purification methods are used to prolong the life of the patient (and kidney transplantation is performed in people).

Unfortunately, in most cases, CRF in Shar-Pei is diagnosed at the last stage, when any manipulations are already meaningless (veterinarians understand this very well, but rarely refuse the owners' request to "do at least something").

“How could this happen? Just a few days ago my shar-pei was running, jumping, enjoying life and was completely healthy. And suddenly - such a terrible diagnosis! I've lost count of how many times I've heard those words. Indeed, from the outside, everything looks as if someone suddenly turned off the light inside the dog. But this is a misleading impression, behind which is our inability to catch small signals of a big trouble.

How is kidney failure diagnosed in Shar Pei?

HPN cannot be cured. But the sooner it is detected, the greater the chance that the dog will live longer, despite diseased kidneys. In order not to miss the onset of CRF, veterinarians, in particular, Jeff Widt (who has been dealing with Shar-Pei problems at the National Club in the USA for more than 20 years), advise to conduct simple diagnostic tests for all Shar-Pei, starting at the age of two, at least once a year, and starting from 5 years - twice a year. About what exactly tests are coming speech?

BLOOD STUDY
Usually, creatinine and urea nitrogen levels are examined to diagnose kidney disease. Additionally, it is recommended to define the following biochemical parameters blood: phosphorus, calcium and sodium/potassium ratio. A general blood test is also informative, in particular the composition of erythrocytes, platelets, leukocytes, lymphocytes and hematocrit.

creatinine is the end product of protein metabolism. It is formed in the liver, then released into the blood, participates in the energy metabolism of muscle and other tissues, and is excreted from the body by the kidneys with urine, so creatinine is very important indicator kidney activity. A high level of creatinine in the blood almost always means problems with the kidneys. This does not indicate the nature of the problem - chronic or acute - and does not indicate its cause and how to solve it, but indicates that the dog has a kidney problem and that action needs to be taken.

Normal levels of creatinine in a dog's blood- 26-120 µmol / l (according to some laboratory reference books, the upper limit of the norm is 140 µmol / l). Please note that the increase in the level of creatinine in the blood can be facilitated by taking certain medications (which is usually written in the instructions for them), as well as with dehydration and mechanical damage to the muscles. Creatinine is artificially lowered when taking corticosteroids (in some cases, this property of hormonal drugs is used by veterinarians to temporarily alleviate the intoxication of a dog with CRF).
Early stages of kidney failure: It is believed that an increase in creatinine from 140 to 200 µmol / l or slightly higher indicates a moderate, or initial, stage of renal failure.
moderate renal failure: Creatinine values ​​between 200 and 398 µmol/L, but even at these values, your dog may still show no symptoms (other than increased water intake and urination).
Severe degree of renal failure: creatinine above 398 µmol/l. This level of creatinine is usually accompanied by clinical symptoms such as vomiting and loss of appetite.
terminal stage: creatinine above 600 µmol/l. This level indicates that the kidneys have practically lost their functions, there is a strong irreversible poisoning of the body with nitrogenous compounds and other "waste", which are normally filtered and removed from the body by the kidneys. Lethal outcome is inevitable and close.

UREA(sometimes "urea nitrogen") - active substance, the main product of protein breakdown, is produced by the liver from ammonia and is involved in the process of concentrating urine. In the process of synthesis of urea, ammonia is neutralized - a very toxic substance. Urea is excreted from the body by the kidneys. Accordingly, if urea is poorly excreted from the blood, this means a violation of the excretory function of the kidneys.

Normal urea values in the blood - 3.5-9.2 mmol / l. Increasing it to 12.5 mmol/l if the dog has not fasted for 12 hours prior to analysis is not a cause for concern if other parameters (blood creatinine and urine specific gravity) are normal. Dehydration and stress can also contribute to an increase in urea levels.
The initial stage of chronic renal failure: the level of urea up to 18 mmol / l. The dog can behave like a completely healthy dog.
moderate stage: urea up to 28 mmol/l. At this stage, the dog may refuse to eat, it has a specific smell of "urine" from the mouth.
severe stage: urea level above 28 mmol/l. This is evidence of uremia and is usually accompanied by clinical symptoms such as vomiting and loss of appetite.
terminal stage: urea above 50 mmol/l.

PHOSPHORUS AND CALCIUM: As a rule, with progressive chronic renal failure, the calcium-phosphorus balance is disturbed. The content of phosphorus in the blood rises, and calcium falls. High levels of phosphorus are dangerous and need to be controlled. Since calcium is the “building material” of bone tissue, poor healing of cracks and fractures in a dog may indicate hidden kidney problems.

SODIUM AND POTASSIUM RATIO: If the sodium/potassium ratio (sodium value divided by potassium value) in your dog's blood is below normal (27 or less), then this indicates Addison's disease (hypoadrenocorticism), which may be the cause of kidney failure. Addison's disease, if left untreated, can be fatal, but it is treatable. It is often misdiagnosed as kidney disease, so it is worth doing further testing even if the sodium/potassium ratio is normal, especially in young bitches.

HEMATOCRIT (HCT): an indicator that reflects the proportion of red blood cells in the total blood volume. It determines whether the blood in the body is renewed. The lower the hematocrit value, the lower the volume of red blood cells in the blood and the more plasma in it. In simple terms, this means that the blood is “aging”, and the internal organs do not have time to create new red blood cells to replace the dying ones. This indicator is associated with kidney problems in this way: the kidneys are the main producer of erythropoietin, a hormone that stimulates the formation of red blood cells. Therefore, in renal failure, the production of erythropoietin sharply decreases, therefore, less erythrocytes are produced, and their share in the total blood volume falls, as indicated by such an indicator as hematocrit.

URINE STUDY

DENSITY. Urinalysis may be important in diagnosing kidney disease. Often the first sign of a dog's kidney problems is a low urine specific gravity (1.020 or lower). Moreover, this symptom appears much earlier than the first deviations in blood tests. The greatest accuracy of the analysis is achieved if the "first daily urine" is taken for analysis, that is, when your dog urinates for the first time after a night.
If severe azotemia (high levels of urea and creatinine in the blood) remains normal (1.030 or higher), then this is a sign of prerenal (prerenal) problems such as Addison's disease, or postrenal problems such as urolithiasis (or nephrolithiasis) .

PROTEIN. Other signs of kidney disease may be the presence of protein in the urine, but a small amount, provided that the specific gravity is high (1.035 and above), is considered normal. Be aware that if urine is taken through a catheter or manual stimulation of the bladder, there may be some blood in the urine, which is detected in the analysis as traces of protein. For this reason, it is better to examine urine obtained naturally- just use a ladle or a small bowl to collect the urine when the dog pees. If you are doing this at home, then immediately put the urine in the refrigerator, and then deliver it to the veterinarian as soon as possible. It is best to allow the dog to start urinating before the urine is collected to avoid entering the sample for bacteria analysis.
The appearance of protein in the urine with normal blood counts may be the first signal to start kidney problems. However, there can be many reasons for the appearance of protein in the urine. "When diagnosing protein-losing kidney disease, some of the most likely infections to consider are brucellosis, piroplasmosis, leptospirosis, boreliosis (Lyme disease), leishmaniasis, chronic bacterial infections, and heartworms. Non-infectious causes include, but are not limited to, an inflammatory process in bowel, systemic lupus, and hyperadrenocorticism (Cushing's disease)" (from Protein Losing Nephropathy: An Overview; by Bayer). There is a study of urine, which is called electrophoresis. This diagnostic tool allows you to understand the cause of the appearance of protein in the urine.

BACTERIA. Often the cause of kidney disease (pyelonephritis) is a urinary tract infection. Bacterial culture is the only way to rule out a urinary tract infection, and to find out what antibiotics to use to treat it, if found. It is important that urine sampling for bakposev is done in accordance with all the rules in order to avoid "dirt" in the analysis. In some cases, the use of a catheter for these purposes is justified (this manipulation is carried out in the clinic, and not at home).

ULTRASOUND DIAGNOSIS (US)

Although many veterinarians recommend doing an ultrasound to monitor the condition of the kidneys, the value of ultrasound as diagnostic method Dogs are the big question. Hand on heart, a diagnostic method in which you can confuse puppies with pyometra, not see 8 puppies at the end of pregnancy, see puppies where they are not (and all this is not a mistake of one specialist, but the results of ultrasound in different clinics, different dogs, at different times), is distrustful. I personally know several dogs that have died as a result of CRF that have had perfect or slightly abnormal ultrasound results. Therefore, if we are not talking about the diagnosis of kidney stones, I consider it pointless to waste time and money on ultrasound.

Symptoms of latent renal failure in sharpei

As I have already said, most owners detect CRF in dogs only when it is already in a severe or terminal stage. This happens because the dog does not know how to complain about bouts of malaise, discomfort in some part of the body, and we are often not attentive enough to notice changes in her behavior, habits, eating habits, and so on.
The first rule of a good owner: do not wait for the dog to show obvious signs of illness, then it may be too late to do something. If your dog is older than 3-4 years old, watch for the slightest deviations from the usual behavior. Maybe your dog has started sleeping more, lying down more, less active? Or maybe she began to periodically arrange fasting days for herself, which was not the case before? Maybe she began to eat worse food that she liked? Or is she unreasonably sad? Any deviations from the usual matter, because dogs are slaves of habits, and while they are doing well, they live and act according to the algorithm developed in childhood. If changes occur in it, do not hesitate to take your pet to the laboratory and check the blood and urine for possible deviations in the work of the kidneys. Dr. Jeff Widt recommends paying attention to the values ​​of creatinine and urea, even in cases where they do not yet exceed the norm, but have already come close to its upper limit. If at the same time the specific gravity of urine is not more than 1.020, then we can speak with a sufficient degree of confidence about the first signals of CRF. The same is true if, at a normal density of urine, protein is found in it. In my practice, there was a case of the so-called "isolated proteinuria" - a significant amount of protein in the urine, and at the same time completely normal tests blood and ultrasound. The dog in question died 9 months later from CRF.

Obvious signs of kidney failure

Most often, sadly, the owners realize when the dog demonstrates one of the following (or all at once):

Refuses to eat, loses weight
- drink a lot and pee a lot (little)
- began to make puddles at home
- a smell similar to urine appeared from the mouth
- there were incomprehensible bouts of vomiting, nausea
- temperature
- moves reluctantly, bends the back, cannot sit or lie down normally

All these signs of malaise can mean CRF in the middle or severe (up to the terminal) stage.

Diagnosis made...

If this happens, the first thing to do is to pull yourself together. There is no need to be under illusions about the prospects for the "treatment" of CRF, especially if it is caught in the last stages. In the event that the creatinine level is already above 600 µmol/l, and the urea has exceeded 60 mmol/l, any manipulations with the dog will only prolong its days of painful illness. Unfortunately, few doctors and owners are stopped by the fact that a dog with similar tests and external symptoms can no longer be helped and prolong life in the form in which the dog needs it (bed rest and life on droppers and dialysis for a dog unnecessary and incomprehensible). At the same time, if you turned out to be sensitive and attentive enough to your dog, and you managed to catch CRF at an early stage, you need to avoid panic and unnecessary emotions, enlisting the help of an intelligent veterinarian, develop an action plan to maintain your Shar Pei's quality of life. How to deal with progressive intoxication of the body, what drugs to take, what to feed, etc. All your future life with a dog must be subject to strict rules: diet, intake necessary drugs regular blood and urine checks

BLOOD PURIFICATION

A dog with chronic renal failure needs fluid therapy. Any experienced veterinarian knows this and, after making a diagnosis, prescribes a course of droppers with saline and nutrients (glucose, cocarboxylase, etc.), as well as additional drugs, depending on the severity of the disease and the depth of involvement of other internal organs in this process ( pancreas, liver, heart, gastrointestinal tract(GIT) suffer significantly in chronic renal failure). Intravenous injections "feed" the body (especially if the dog hardly eats), supplying pure energy in the form of glucose, cocarboxylase, "wash" the blood, nourish the tissues. And infusions (droppers) are a way to lower the level of urea and creatinine in the blood. However, if the level of these toxins in the blood is high, the result from the IVs is likely to be negligible.
In the middle and severe stages of chronic renal failure, the most in an efficient way cleaning the blood of toxins that the kidneys stop removing is plasmapheresis. In the severe stage of CRF, this is practically the only way to radically and quickly cleanse the blood of a sick dog and thereby give her a little more time to live a normal life (as far as possible). Unfortunately, even in Moscow it is practiced in only one or two veterinary clinics.

Plasmapheresis(from the Greek "apheresis" - "removal") - a modern, often uncontested, method of treating diseases of various organs and systems. The procedure is to separate the blood into cellular elements(erythrocytes, leukocytes, platelets, etc.) and plasma, i.e. liquid part blood, in which pathological and metabolic components are dissolved - carriers of the causes of diseases. The plasma is separated from the cellular elements and removed along with toxins and pathological elements, it is replaced in the body with various sterile solutions, the cellular elements are returned to the patient.

Second after plasmapheresis effective method blood purification - hemosorption. In the initial and middle stages of CKD, hemosorption sessions can help stabilize the condition of a dog with CKD at a more or less acceptable level, so that the dog can enjoy a normal life for some time.

Hemosorption(from hemo... and Latin sorbeo - I absorb), a method of extrarenal blood purification from toxic substances by pumping it through a column with a sorbent ( activated carbon, ion exchange resins).

Hemodialysis is the most common method of blood purification in severe stages of CRF. It is also called "apparatus artificial kidney and is widely used in humans. As for the use in dogs, then in terms of effectiveness, I would give it the third place after plasmapheresis and hemosorption. Curiously, hemodialysis in humans is indicated in the terminal stages of chronic renal failure, when urea exceeds 30 mmol/l, and creatinine 700 µmol/l. But many veterinarians believe that doing hemodialysis to a dog with such high creatinine is already pointless. At least, I know cases of refusal of hemodialysis to dogs in which the level of creatinine and urea corresponded to the terminal stage of the disease.

Hemodialysis(haemodialysis; Greek haima blood + dialysis decomposition, separation) - a method of extrarenal blood purification from substances with small and medium molecular weight by diffusion and partly by convection (ultrafiltration). A procedure in which the patient's blood and dialysis solution are pumped from different sides of a semi-permeable membrane towards each other. In this case, metabolic products pass through the membrane from the blood into the solution and are carried away by it. Excess fluid from the patient's body also passes through the membrane under the influence of the pressure difference created by the dialysis machine, which controls the procedure and ensures its safety.

Peritoneal dialysis is another way to cleanse the body of toxins that are not removed from it by the kidneys. It is believed that it is technically simpler than hemodialysis and cheaper. In terms of actual effectiveness for dogs with CKD, based on the evidence collected, I would put it in 4th place.

Peritoneal dialysis(anat. peritoneum peritoneum: Greek dialysis decomposition, separation) - a method of cleansing the blood and the body of harmful substances, based on the high absorption capacity of the peritoneum ( serous membrane abdominal cavity), in which the abdominal cavity through special holes is washed with medicinal solutions in large quantities

The owner of a Shar-Pei with chronic renal failure should remember that all these procedures do not give a 100% guarantee of alleviating the condition of the dog and may have side effects from the side of the heart. However, in a serious stage of CRF, without blood purification by one of these methods is the only chance to prolong the normal existence of the animal. Moreover, you will have to clean the blood and monitor its chemical composition on a regular basis, otherwise it’s better not to even start.

Nutrition and supplements

The diet of a dog with CRF is a separate big topic. Mary Strauss has an excellent collection of materials on the principles of nutrition selection for a sick dog, which we publish with her consent in a separate large article.

It's important to know

If a dog with CKD has an elevated serum phosphorus level, discuss the need for phosphorus-binding drugs with your doctor. its excess is dangerous and causes additional harm to the patient.

The most natural way to control the level of phosphorus in the body is to consume calcium. If you are feeding your dog home cooking or raw food, it is easiest to add ground eggshells in a coffee grinder to food with a small amount of vitamin C (1 teaspoon of dry ground eggshell from a raw egg contains an average of 2.2 mg of elemental calcium, the most digestible form, by the way). Moreover, it is worth doing this without waiting for the level of phosphorus in the blood to go beyond the norm, i.e. With preventive purpose. The average dose per feeding is 1/2-3/4 teaspoon for every 0.5 kg of food.

by the most effective drug phosphorus binder is aluminum hydroxide. It is familiar to many from Almagel, Maalox, etc., but aluminum hydroxide is preferred in its pure form, in the form of a gel (for example, a preparation with trade name Aludrox). This drug should be used when the level of phosphorus is clearly elevated, especially if the level of calcium is also elevated in parallel.

Among finished products calcium used to bind phosphorus, it is worth highlighting calcium acetate, since it needs 40% less to achieve the same result as when using calcium carbonate or citrate. This is important when it comes to using calcium in a dog with normal or near-elevated calcium levels in the blood. Approximate dosages for calcium acetate are 60 mg per kg of animal weight, for the other two forms - 100 mg per kg.

Do not use for phosphorus binding complex preparations calcium, since they usually also contain phosphorus.

All phosphorus-binding preparations should be given strictly with or immediately after meals to prevent excess phosphorus in the blood from food.

The daily intake of calcium and phosphorus into the body of a sick dog should correspond to a ratio of 3:1.

Euthanasia

The most difficult and controversial issue is to wait until a loved one dies of pain and exhaustion, or stop suffering when everything has been tried, and there is no longer a chance to prolong a normal life, and how to understand when this moment will come?
There is a place in Switzerland where terminally ill, suffering people come with a one-way ticket. There they voluntarily die, breaking the chain of torment that accompanies their illness. We don't give dogs that choice. But this does not mean that they do not suffer before death. Ask any competent doctor what kidney failure is in its last stage. People live on the strongest painkillers, in fact, drugs. Dogs don't get that either. When I hear from the owners “my dog ​​didn’t suffer, she quietly left on her own, and I’m glad that I didn’t have to euthanize her,” I want to ask if you know what constant pain in the abdomen, not passing nausea, periodically ending in vomiting of pieces of mucous mixed with gastric blood? Do you know what a terrible dull headache that does not go away, from which there is no escape? Do you know what it's like to have weakness all over your body, dull pain in your joints all the time? Now put it all together - this is what a dog in the terminal stage of CRF is only roughly experiencing. The Shar Pei is an amazingly patient creature. And the calmness, lethargy, drowsiness of a hopelessly ill dog does not mean that it is slowly and painlessly fading away from exhaustion. It's just not customary for dogs to moan and complain. They suffer in silence. At the same time, one should not forget that death from kidney failure can be preceded by agony. By refusing to euthanize a terminally ill dog in time, you run the risk of being face to face with terrible care, as happened with one of my friends: watching your beloved creature writhe and screaming in pain was unbearable to such an extent that the owner grabbed the knife several times to kill her and end the torment, the only thing that stopped her was that she did not know how to do it for sure.
For 12.5 years of living side by side with the Shar-Pei, I had to resort to euthanasia with CRF three times. Two of the deceased were elderly Shar-Peis picked up on the street, the third was a young bitch who received CRF as a result of an attack of acute renal failure. So I know exactly what I'm talking about...

If the person has the following signs of the end stage of chronic renal failure:
- the sick dog does not eat
- drinks, but after it vomits water with blood, and in general often vomits
- practically does not move unless absolutely necessary, and on walks stands like a bull or lies on the ground
- she has bleeding gums and a very strong smell of urine from her mouth
- the level of creatinine in the blood is above 800, urea - above 60
- if the dog cannot find a comfortable position to fall asleep

Believe me, there is no point and no need to continue to "treat" a dying animal. The best thing you can do now is to give your beloved dog a chance to leave.

The myth of healthy lines

Shar Pei owners should understand one important truth for themselves: there are no lines that are healthy from kidney problems. Whether your dog will live to old age, or die at 3-5 years old, depends only on your personal luck. For example, an 8.5-year-old male dog lives and lives in my house, and his daughter died in my arms at the age of 3.5 from kidney failure. And the point here is not how breeders conduct breeding work, but the fact that the genes that encode hereditary diseases are recessive and can hide for several generations in the genotype of healthy dogs. In addition, we do not have kennels that work independently, without the use of dogs from other kennels. It is extremely rare that breeders can boast of pedigrees that would include only dogs of their own breeding several generations ago. And this means that no breeder can give a 100% guarantee of health to any of their puppies. By saying “we use dogs of healthy lines” breeders are wishful thinking, since in order to judge the health of lines, it is necessary to track the entire population, and not a few outstanding dogs from it. Not to mention that guaranteeing the health of other people's lines used in their breeding is a bold but stupid act. The level of breeding both in our country and abroad is not yet high enough for breeders to be frank with each other about problems with their dogs.

Genitourinary system of dogs

Renal failure in dogs - treatment, symptoms and pathogenesis

Renal failure in dogs is a disease that requires a non-standard approach to treatment. key point therapy is a diet for renal failure.

In dogs, as in all vertebrates, all toxic compounds that have been synthesized in the process of metabolism or come from outside (for example, in case of poisoning) are excreted from the body with urine. Therefore, when urination is inhibited in the internal environment, the accumulation of toxins begins, disrupting the work of all organs and systems.

Renal failure in dogs is a common, severe form. renal pathology in dogs, which in the absence of timely veterinary care can lead to the death of the animal.

Kidney failure can be acute (ARF) and chronic (CRF). OPN develops quickly, within a few hours, chronic - slowly - for months, years. AKI and CRF differ not only in time, but also in manifestations and prognosis. The most important prognostic factor is that ARF is potentially curable, but CKD is not. The development of chronic kidney disease in dogs can be slowed down, but not stopped.

The main causes of the disease

Renal failure is not independent disease, but a complication of renal or extrarenal pathology.

The causes of acute renal failure are diseases that can be complicated by its development. They can be divided into three groups:

• - All situations associated with a lack of blood supply to the kidneys, for example, acute blood loss due to wounds and injuries of the dog.
• - The urinary function of the kidneys can be blocked with direct alteration and / or destruction of the renal tissue. This group of causes includes infectious inflammatory diseases kidneys (glomerulonephritis, pyelonephritis), systemic inflammatory diseases (leptospirosis), the effect of nephrotoxic compounds (heavy metal salts, carbon tetrachloride, organic solvents, aminoglycoside antibiotics, snake and mushroom venoms, etc.).
• - Inhibition of urine formation can be caused by a violation of its outflow through the urinary tract (ureters). Let's take urolithiasis as an example.

Chronic renal failure can arise and develop as an outcome of many acquired animal kidney diseases. Among them are glomerulo- and pyelonephritis, obstructive diseases of the urinary tract, etc. If such a pathology in a dog was not recognized and treated in a timely manner, then with a high probability the process of death of nephrons (structural and functional units of the kidney) may begin with the loss of their contribution to urine formation. The loss of 65-75% of structural and functional units is critical - from that moment on, clinical signs of CRF appear.

In addition, a number of dog breeds are characterized by hereditary nephropathology, which, under appropriate circumstances, can provoke the onset and development of CRF. Among these breeds: Shar-Pei English, Fox Terrier, Bull Terrier, Cocker Spaniel, English Spaniel, Doberman Pinscher, samoyed husky, basenji, rottweiler, bernese mountain dog, german shepherd, norwegian elkhound, shih tzu, chow chow, golden retriever, standard poodle, welsh corti, beagle.

Relevant circumstances should be understood as the presence (at least in the past) of the above causes of renal failure in dogs, the age of the animal (over 10 years), the features of its maintenance (a comfortable room for this breed, care, feeding and exercise). According to these principles, a risk group is formed and, ideally, each owner should be familiar with this. The best prevention for dogs from this group, there will be a regular veterinary examination with the obligatory determination of the level of creatinine in the blood plasma and the specific gravity of the urine.

Clinical picture

Many animal diseases are characterized by diseases with nonspecific development of clinical signs in different breeds and ages. One such disease is kidney failure in dogs, the symptoms of which may develop differently in each case.

At the beginning of the development of acute renal failure (ARF), only the symptoms of the underlying disease that caused the complication are noticeable. Signs of kidney failure as such are rarely recognized. Only with careful monitoring are subtle changes in the blood detected. However, it is during this period of time that there is the greatest number of opportunities for the normalization of kidney function.

In the future, the owner pays attention to frequent urges on urination and at the same time a sharp decrease or complete absence of the soaked liquid. The dog is weakened, depressed, lies for a long time. Appetite is absent, nausea, vomiting, diarrhea, appearance of ammonia smell on the exhale. Body temperature is reduced by 1.5-2 degrees. In the blood, there are pronounced signs of impaired urination in the kidneys - an increase in the concentration of nitrogen-containing creatinine and urea.

Without timely veterinary care, there is high probability lethal outcome of the animal. With a favorable course under the conditions of the treatment, the complete restoration of kidney function in dogs lasts at least 6-12 months.

Chronic renal failure (CRF) in dogs is latent at first. During this period, only non-specific signs can be seen in a sick dog: malaise, weakness, loss of appetite. When conducting laboratory tests and functional tests possible changes characteristic of the underlying disease.

In the future, the owners begin to pay attention to frequent and profuse urination, as well as increased thirst of the pet. The amount of liquid drunk per day is more than 100 ml/kg of body weight of the animal. At the same time, the general condition of the dog, its physical activity practically does not suffer. This period of chronic renal failure is called the stage of compensated insufficiency - the kidneys cope with the purification of the blood from toxic agents to be eliminated by increasing the amount of urine. Laboratory examination reveals moderate hyperazotemia.

As the process progresses, the stage of compensated insufficiency is replaced by a decompensation phase. The owner notices more and more signs of trouble in his dog. The general condition worsens, physical activity and endurance decrease, weight decreases. The animal still drinks a lot. Frequent urination persists, but there are false urges on him. There is a lack of appetite, nausea, vomiting, constipation or diarrhea. Visual impairments up to blindness are possible. Stomatitis develops with ulceration of the mucous membrane and a characteristic smell from the mouth. In the blood, the level of creatinine and urea increases, red blood cells (hematuria or blood in the urine) are found in the urine.

In the final (terminal) stage - at the peak of the progression of chronic renal failure - uremia (urinary blood) is formed - high azotemia with uremic syndrome. It has many components, including severe violations rhythm (one of the causes of death), ossification (a syndrome of extraosseous tissue calcification), renal osteodystrophy and osteomalacia (softening of bone tissue), digestive disorders, neurological disorders, arterial hypertension, shock and coma.

Diagnostics

To make a diagnosis of renal failure, a conversation between a veterinarian and the owner of a sick dog, an objective examination of the animal, laboratory and instrumental examinations is necessary. Laboratory tests are blood and urine tests. Instrumental examination includes radiography and ultrasound.

Also, the veterinarian will conduct a differential diagnosis between acute and chronic forms of renal failure.

Treatment

Renal failure in dogs can only be treated by a veterinarian.

There are several principles of treatment of acute renal failure:

• 1. Identification and elimination of the cause of acute renal failure.
• 2. Restoration of the urinary function of the kidneys - is achieved by correcting the blood filling of the vascular bed of the kidneys (infusion therapy), normalizing intrarenal hemodynamics ( vasodilators, antiplatelet agents and, if necessary, anticoagulants).

• 3. Medical elimination metabolic shifts underlying organ dysfunctions - aimed at eliminating tissue energy deficiency, stimulating protein synthesis processes. Intravenous administration of a glucose solution, B vitamins, adenosine triphosphate, riboxin are shown; drugs of anabolic type of action (solutions of amino acids).
• 4. Measures to detoxify the internal environment of the body include the appointment of a diuretic (furosemide), which is used until the development of persistent polyuria.

Treatment of chronic renal failure

CRF in animals in decompensated and, moreover, in the terminal stage does not have a favorable prognosis. The period of compensated insufficiency is quite curable and the main therapeutic measure is the correct food and drinking regimen of a sick dog. The veterinarian will help to make a special low-protein, but high-calorie diet with a sufficient content of trace elements, salts and fats.

What to feed a dog with kidney failure.

• - This is a food with a moderate or low (specified by the veterinarian) protein content with the minimum amount phosphorus. The best sources of such protein for a dog with CKD are eggs, as well as fresh meat. These foods are allowed as complementary foods, even if dry dog ​​food is used.
• - A mandatory requirement is the exclusion from the diet of phosphorus-containing products - bones, fish with bones, organ meats (liver, kidneys), cheese;
• - Animal feed must contain a sufficient amount of fat. The following sources are recommended: fatty meat, butter and coconut oil, egg yolks, yogurt. Do not ask for sunflower, corn, soybean, and fish oils.
• - Carbohydrates in the form of cereals and starchy vegetables in the diet of a sick dog should be half of the total amount of food. Cereals or vegetables are selected with the lowest phosphorus content, namely White rice and semolina, white potatoes and yams.
• On sale there are special dry food for dogs diagnosed with CRF. They should be selected according to the recommendation of the veterinarian.

Forecast

Acute renal failure in dogs is a reversible process. Therefore, the decisive factor in the recovery of the animal is the timeliness and adequacy of the treatment.

In the chronic form of the disease, the main task of the owner and veterinarian is now early detection complications and the maximum possible extension of the compensation stage. Unfortunately, there is currently no effective treatment for decompensated and end-stage renal failure. If you have any questions, you can ask them in. In addition, you may be interested in kidney failure in cats.

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2015-10-03 20:34:09

Very helpful article, thanks.

2015-10-03 20:37:48

My pleasure:)

2016-03-17 11:17:23

Everything I needed to know was found in your article, thanks!

2016-03-18 13:13:20

Elena, we are very glad that you found answers to your questions. Thank you for your feedback.

2016-05-01 23:00:14

I have a dog ch-hua 15 years old, suffers from kidney failure, recently fell ill. The doctor says that she should only be fed special food for this disease, pate. But before the illness, I always fed her live food, rice with chicken breast, minced veal with cobwebs, boiled. Is it possible to feed her with dietary live food, since she vomits from canned medical food, does not want to eat? Thank you

2016-05-02 08:05:28

Irina, natural food, of course, it’s better, however, based on the data from blood and urine tests, you may have to exclude some foods from such a diet.

2016-05-02 12:42:53

Tell me, is it possible to give rice by adding a little chicken broth, raw yolks, cottage cheese? Thank you!

2016-05-02 12:53:12

If previously the animal ate such a diet and there were no problems, for example, in the form of allergic reactions or indigestion, then it is completely. However, do not forget that the age of the dog is already quite respectful, so it is better to supplement the diet and, in general, somehow change it, in accordance with the data of the blood and urine tests, as well as the general condition of the animal. By the way, it is better to replace the chicken with fresh pork with a small layer of fat (you need to know the state of the liver and pancreas), and alternate rice with semolina or wheat porridge. If your doctor insists on using special pies so that there are no such reactions in the animal, the change in the transition of the diet should be done slowly, over several weeks, gradually replacing part of the usual food with a pate .. or whatever you have.

2016-05-02 15:35:09

Thank you, so I realized that if she always ate live food, immediately on canned pate, which the doctor recommended, move on gradually, adding to the diet

2016-05-02 15:53:50

Yes, Irina. Plus, a comprehensive biochemical blood test is desirable.

2016-05-02 23:28:23

Sorry, I probably already got you, the analysis is creatinine 243, urea 16.8. I know the bad ones, so I worry so as not to harm, the dog is weak, so I want to add egg yolk to the therapeutic pate, rice with the addition of broth, semolina, unlike the pate she eats it with pleasure, is it okay? thanks

Determination of the ratio of urine protein to creatinine - standard for early diagnosis of kidney disease.

Why determine the protein in the urine?

Determining the concentration of protein in the urine is a mandatory and important element of the study of urine.

The detection and quantification of proteinuria is important not only in the diagnosis of many primary and secondary kidney diseases, but the assessment of changes in the severity of proteinuria in dynamics carries information about the course of the pathological process and the effectiveness of the treatment. The detection of protein in the urine, even in trace amounts, should alert for possible kidney or urinary tract disease and requires re-analysis.

The appearance of protein in the urine is a harbinger of kidney failure. This phenomenon is also called proteinuria. The entry of protein with a higher molecular weight into the urine is caused by damage to the basement membrane of the kidneys. At the same time, low molecular weight compounds (including creatinine) are still filtered as before, and their concentration in urine and blood does not change.

Elevated protein in the urine indicates a pathology of the kidneys. This is an early indicator of nephron damage in the absence of concomitant changes in the level of urea and creatinine, determined classically in serum. The causes of damage can be drugs (aminoglycosides, cyclosporine), heavy metals(lead), analgesics, renal ischemia, past illnesses and metabolic diseases. It is possible to expand the diagnosis of proteinuria by determining the ratio of protein and creatinine in the urine. This study much more objectively and is used to determine the severity of proteinuria.

Why aren't urine test strips good for diagnosing proteinuria?

Currently, diagnostic strips are increasingly used to determine the protein in the urine. It is a qualitative and semi-quantitative method. The protein content in the urine is judged by the intensity of the blue-green color that develops after contact of the reaction zone with urine. The result is evaluated visually or using urine analyzers. Despite the great popularity and obvious advantages of dry chemistry methods (simplicity, speed of analysis), these methods of urinalysis in general and protein determination in particular are not without serious shortcomings. One of them, leading to a distortion of diagnostic information, is the high sensitivity of the indicator to albumin compared to other proteins. In this regard, the test strips are mainly adapted to the detection of selective glomerular proteinuria, when almost all of the urine protein is represented by albumin. With the progression of changes and the transition of selective glomerular proteinuria to non-selective (the appearance of globulins in the urine), the results of protein determination are underestimated compared to the true values. This fact makes it impossible to use this method for determining protein in urine to assess the state of the kidneys (glomerular filter) in dynamics. With tubular proteinuria, the results of protein determination are also underestimated. Protein testing with test strips is not a reliable indicator of low levels of proteinuria (most test strips currently available are not capable of detecting protein in urine at concentrations lower than 0.15 g/L). Negative results of protein determination on the strips do not exclude the presence of globulins, hemoglobin, uromucoid, Bence-Jones protein and other paraproteins in the urine.

Mucus flakes with high content glycoproteins (eg. inflammatory processes in urinary tract, pyuria, bacteriuria) can settle on the indicator zone of the strip and lead to false positive results. False positive results may also be associated with high urea concentrations. Poor lighting and poor color perception can cause inaccurate results.

In this regard, the use of diagnostic strips should be limited to primary screening procedures, and the results obtained with their help should be considered as indicative only.

The most sensitive and accurate are colorimetric methods for determining total urine protein, based on specific color reactions of proteins. This study is carried out on a biochemical analyzer, which leads to greater accuracy of the study and allows you to determine the absolute value of the protein content in the urine.

Why is it necessary to determine the ratio of protein to creatinine in urine?

Given the pronounced fluctuations in the level of proteinuria in different times days, it is recommended to determine the concentration of protein and creatinine in a single portion of urine. Since the rate of creatinine release during the day is quite constant and does not depend on changes in the rate of urination, the ratio of protein concentration to creatinine concentration is constant. This ratio correlates well with daily protein excretion and, therefore, can be used to assess the severity of proteinuria.

An important advantage of the method for assessing the severity of proteinuria by the ratio of protein / creatinine is the complete elimination of errors associated with the impossibility or incomplete collection of daily urine.

How to collect urine for analysis?

The material for the study is urine. It is preferable to collect the average portion of morning urine (2-5 ml is enough) in a clean, dry glass or plastic dish with a tightly screwed lid. If possible, urine should be collected immediately in the dishes in which it will be delivered to the laboratory. If this fails, it is advisable to collect it in a clean container (plate, jar, etc.), where there was no urine before (since a precipitate of phosphates forms, which remains even after rinsing and contributes to the decomposition of fresh urine), and then pour all the received portion in a vessel. It is best to collect urine in special plastic cups with lids.

If it is impossible to deliver urine immediately to the laboratory, it can be stored at a temperature of 2 ... 8 * C during the day (if the study is not carried out for other indicators).

If it is not possible to collect urine from the owners, it is possible to take a sample by catheterization or bladder puncture .

How to interpret the results and what is the norm?

Urine protein to urine creatinine ratio ( total protein mg / ml: creatinine mg / ml) in dogs and cats should normally be no more than 0,2 .

Borderline proteinuria may be due to tubular or glomerular kidney disease.

In the case of moderate or severe persistent proteinuria, accompanied by a sediment without signs of hematuria and inflammation, there are prerequisites for suspicion of glomerulonephritis or renal amyloidosis.

You can get more detailed information about kidney diseases (including chronic kidney "failure", chronic kidney disease) from veterinary nephrologists, as well as conduct a biochemical analysis of urine in our laboratory.