Myasthenia acute myasthenic crisis. Myasthenia gravis: etiology, classification, clinic, diagnosis, principles of treatment, care. Myasthenic crisis, clinic, first aid. Crisis during starvation

The cause of a myasthenic crisis is usually a sudden worsening of a pre-existing myasthenia due to an error in treatment or an intercurrent disease, most often an infection. Only in rare cases, myasthenic crisis is the debut manifestation of myasthenia gravis. A distinction is made between an acute crisis with respiratory failure and sudden respiratory arrest, heart failure due to severe cardiac arrhythmias caused by myocarditis, and a subacute crisis with decompensation of the functionality of acetylcholine receptors and weakness of the respiratory and / or bulbar muscles.

Symptoms and signs of myasthenic crisis

Ptosis and diplopia may be seen. Reflexes and sensitivity are not disturbed.

Dyspnea. At first glance, there is no impression that the patient's condition is serious. The combination of facial expression and weakness of the respiratory muscles creates a false impression of the patient's satisfactory condition.

Bulvar violations carry a potential danger of violation of the protective function of the upper respiratory tract and the development of aspiration pneumonia.

Fatigue and respiratory failure lead to the development of coma.

Reception of penicillamine (may cause the development of a syndrome identical to idiopathic myasthenia gravis).

Common Predisposing Factors for Myasthenic Crisis

Infection, surgery, medication. Note! Glucocorticoids used to treat myasthenia gravis may initially exacerbate.

Severity score

The most important indicator of crisis severity is lung capacity. Arterial blood gases are an insufficiently sensitive criterion; their determination makes it possible to detect hypercapnia already at a late stage.

Boulevard violations. cholinergic crisis.

Sometimes it is impossible to differentiate between progressive myasthenia gravis and an excess effect of anticholinesterase therapy (which leads to muscle weakness as a result of depolarization blockade) on the basis of clinical data alone. They decide on the abolition of anticholinesterase drugs only after consultation with a neurologist. It should be remembered that a cholinergic crisis is much less common than a myasthenic one.

Treatment of myasthenic crisis

Stabilize the patient's condition. It should be ensured that there are no electrolyte disturbances (decrease in the concentration of potassium, calcium, increase in the concentration of magnesium), and also that the patient is not taking drugs that aggravate muscle weakness.

Treatment is aimed at maintaining vital signs, which includes intubation and connection to a ventilator. The measures of symptomatic therapy, as well as differential diagnosis with a cholinergic crisis, include the introduction of a short-acting anticholinesterase agent - edrophonium chloride. When the condition improves, treatment is continued with longer-acting anticholinesterase agents administered parenterally or orally (for example, pyridostigmine (calimin)).

When switching from oral to intravenous administration, it must be remembered that the ratio of equivalent doses administered intravenously and orally is 1:30!

At the same time, additional measures are taken: the appointment of anticholinergics (atropine) in the presence of a large amount of mucus, adequate replenishment of potassium deficiency (plasma concentration should be at the upper limit of normal), treatment of concomitant diseases. After removal from the acute state, immunomodulatory therapy is prescribed.

Decide whether to conduct a test with edrophonium (tensilon test). Anticholinesterase therapy is effective if a cholinesterase crisis is excluded. If there is no effect after the introduction of edrophonium, the correctness of the diagnosis is assessed. Cancel all anticholinesterase drugs for 72 hours. The test with the introduction of edrophonium can be repeated after a while.

Immunosuppressive therapy should be carried out under the supervision of a neurologist: the appointment of prednisone according to an alternating regimen leads to improvement. However, such treatment should be carried out with caution, since muscle weakness may occur at the beginning of treatment with glucocorticoids. High doses of glucocorticoids are prescribed until remission is achieved. Azathioprine is also used for maintenance therapy, but the effect is achieved only after a few months of its use.

Plasmapheresis removes circulating antibodies from the bloodstream. Usually, a replacement of 50 ml / (kgxday) is carried out for several days.

Long-term therapy with cholinesterase inhibitors is prescribed by a neurologist. The choice of drug determines the patient's response to therapy, but treatment should always be started with pyridostigmine at a dose of 60 mg every 4 hours. The drug can be administered through a tube or, if necessary, replace it with intramuscular injection with neostigmine (at the rate of 1 mg of neostigmine per 60 mg of pyridostigmine).

Relative contraindication - bronchial asthma and arrhythmias. Before the test, atropine should be administered, due to the fact that the administration of edrophonium (belongs to the group of cholinesterase inhibitors) may be accompanied by a severe cholinergic reaction, such as symptomatic bradycardia.

Prepare and label two 1 ml syringes, one with saline and the other with 10 mg of edrophonium.

The muscle to be observed is selected and colleagues are asked to evaluate the strength of the muscle being tested before the test.

The contents of both syringes are injected, while neither the patient nor the doctor should know in what sequence they were injected. Ask the observer to reassess muscle strength after the contents of each syringe are injected.

First, 2 mg (0.2 ml) of edrophonium is injected in a stream and assessed for adverse cholinergic effects. If the patient tolerated this dose, the remaining 0.8 mg (0.8 ml) of the drug is administered after 1 min.

An increase in muscle strength after the appointment of edrophonium-3 indicates the presence of a myasthenic rather than a cholinergic crisis in the patient.

Myasthenic crisis (hereinafter - MK) is a life-threatening condition that is characterized by impaired breathing and swallowing to the extent that compensation is impossible without a set of intensive care and resuscitation measures (including intensive ventilation of the lungs). According to the literature, a crisis course is observed in 30-40% of patients with myasthenia gravis and is more common in women.

The molecular basis of UA is probably a sharp decrease in the number of functioning acetylcholine receptors (hereinafter referred to as AChR) due to a massive attack by their autoantibodies.

It is possible to differentiate UA from other severe conditions accompanied by respiratory disorders by the presence of bulbar syndrome, hypomia, ptosis, asymmetric external ophthalmoparesis, weakness and fatigue of the muscles of the extremities and neck, which decrease in response to the administration of acetylcholinesterase inhibitors (hereinafter referred to as AChE).

There is an idea that the highest incidence of MC occurs in the first 2 years from the onset of the disease, while there is a group of patients in whom the manifestation of myasthenia MC debuts. In the literature, there are cases of the development of MC, accompanied by severe respiratory failure, as the first manifestation of myasthenia gravis (most often with a "late" onset of the disease). The trend towards acute development of myasthenia gravis in the elderly was described by K. Osserman, who identified these patients in a separate group in his classification as an acute "fulminant" malignant form with a late onset of the disease and early atrophies. Currently, many authors note the clinical evolution of myasthenia gravis and a tendency to a significant "aging" of the disease. Thus, researchers note that approximately since the mid-80s of the XX century, the incidence has significantly decreased at a young age and increased by 3 times in old age. This circumstance underlies one of the urgent problems of diagnosing myasthenia gravis in the elderly: currently, according to statistics, 4 out of 5 patients with acute onset of myasthenia gravis at a late age are diagnosed with stroke, botulism (or polymyositis). In most cases, it is possible to determine the triggering factor or a combination of several factors leading to the development of crises, but there is also a “sudden” onset of crises for no apparent reason.

Many authors point to the polyetiological development of MC, on the one hand, and the absence of any visible causes of crises in some patients with myasthenia gravis, on the other. The literature describes a number of factors (exogenous and endogenous) that can provoke the development of exacerbation and MC. Among the most common causes of MC, according to domestic and foreign authors: upper respiratory tract infection (10-27% of cases), aspiration (bacterial) pneumonia (10-16%), surgery - thymectomy (5-17%), onset treatment with high doses of steroids or their cancellation (2 - 5%), pregnancy and childbirth (4 - 7%); in 35 - 42% of cases they do not find the etiological factor of the crisis.

In most cases, MC comes on suddenly and develops rapidly, leaving no time to change treatment tactics and prevent them, so it is important to assess the significance of clinical symptoms, immunological, electrophysiological and pharmacological characteristics that could serve as criteria for predicting the development of MC.

The crisis nature of myasthenia gravis can be predicted already in the onset of the disease. Reliable predictors of a malignant course are facial weakness, bulbar and respiratory disorders, weakness of the muscles of the neck and hands (symptom of "sagging" 3-5 fingers of the hands) and the absence of "classic" oculomotor disorders (double vision) and proximal weakness of the limbs in the clinical pattern of the onset of myasthenia gravis (moreover, a similar selective pattern, having formed early, persists throughout the course of the disease and is observed in patients with the most severe course of the disease, resistant to the main types of pathogenetic therapy - corticosteroids, thymectomy (often during the development of an emergency, patients retain the characteristic selectivity of lesions of individual muscle groups , having the so-called "partial" type of crisis).

According to the result of the study (from 1997 to 2012) N.I. Shcherbakov et al. (FGBU "Scientific Center of Neurology" RAMS, Moscow):

Crises in patients with myasthenia often develop in the first year from the onset of the disease, which is primarily due to late diagnosis and the lack of adequate pathogenetic therapy. The development of a crisis in the later stages of the disease is significantly more often associated with the abolition or reduction of the dose of basic corticosteroid therapy, which reflects the objective difficulties in selecting the minimum maintenance dose of steroids.

MC predominate in women at a young age, in men over 60 years of age. With a "late" onset of the disease, the likelihood of developing crises in women and men is the same.

A feature of myasthenia gravis in the elderly is a tendency to an acute fulminant debut of the disease, up to manifestation with MC, which, as clinical practice shows, is often the cause of an erroneous diagnosis.

Important predictors of a malignant "crisis" course of the disease should be considered the presence of a selective craniobulbar clinical pattern, the combination of myasthenia gravis with thymoma, the absence of an effect on thymectomy in young age groups (up to 40 years), the presence of antibodies (AT) to MTK (specific muscle tyrosine kinase), poor sensitivity patients to acetylcholinesterase inhibitors.

The titer (concentration) of antibodies to AChR has no prognostic value in determining the severity of the course of the disease. Detection of antibodies to MTK in the serum of patients indicates a high risk of developing a malignant crisis course of the disease.

An electrophysiological criterion for a high risk of MC is a decrease in the amplitude of the M-response to the first electrical stimulus in a clinically affected muscle in combination with a small degree of decrement (neuromuscular transmission block) that does not correspond to the severity of paresis.

Most dangerous, life threatening myasthenia gravis are crises - myasthenic and cholinergic.

Myasthenic crisis in myasthenia gravis usually associated with impaired neuromuscular transmission. This may be due to a change in the functional state of the synaptic apparatus under the influence of various factors: malaise, fever, menstruation, overwork, etc., or a decrease in the dose of ACEP for one reason or another. The main danger is the deterioration of bulbar functions, up to aphagia, as well as weakness of the respiratory muscles with an increase in respiratory failure. At the prehospital stage, immediate subcutaneous or even intravenous administration of a 0.05% solution of prozerin is necessary; after 30 minutes, prozerin is re-introduced subcutaneously; mandatory intravenous administration of methylprednisolone - up to 1.5-2 g or prednisolone 1.5-2 mg / kg.

Patients with complications of myasthenia gravis are hospitalized in the centers of neuromuscular pathology or intensive care, neuro-reanimation departments, or intensive care units, where they usually undergo plasmapheresis, and if necessary and possible (the drug is very expensive!) Immunoglobulin G is administered intravenously - 0.4 mg / kg, according to indications IVL is used.

Cholinergic crisis in myasthenia gravis associated with an overdose of anticholinesterase drugs, resulting in symptoms of muscarinic and nicotine intoxication: muscle fasciculations, ptosis, salivary hypersecretion, sweating, pallor, bradycardia, abdominal pain, diarrhea. AHEP are immediately temporarily canceled. In a threatening situation, 0.5-1.0 ml of a 0.1% solution of atropine is slowly injected intravenously. Patients are delivered to the departments indicated above, where they are prescribed mechanical ventilation according to indications, and plasmapheresis is performed.

Myasthenia gravis is a rather rare disease, but the severity of its course determines the importance of timely diagnosis and treatment, especially in the development of a myasthenic crisis. Currently, there is an increase in the development of myasthenia gravis in the elderly. Mortality in myasthenia gravis in people over 60 years old reaches 48.3%. The work analyzed the course of myasthenic crisis in 13 elderly patients. A comparative characteristic of young and elderly patients hospitalized for myasthenic crisis is presented. The predominance of the cholinergic component in the elderly was revealed, which requires longer periods of withdrawal of anticholinesterase drugs in the intensive care unit. The predominant provoking factor in the development of myasthenic crisis in the elderly was an uncontrolled independent increase in the frequency of taking and dosage of anticholinesterase drugs, which indicates the need for systematic monitoring of the clinical manifestations of myasthenia gravis and the dosage of drugs in patients over 60 years of age.

myasthenia gravis

myasthenic crisis

mixed crisis

myasthenia gravis in the elderly.

1. Shkolnik V.M., Kalbus A.I., Baranenko A.N., Pogorelov A.V. Myasthenia gravis: modern approaches to diagnosis and treatment / V.M. Shkolnik and [others] // Ukrainian neurological journal. 2014. - No. 2 (31). - P. 12-17.

Alekseeva T.M., Kosachev V.D., Khalmurzina A.N. Clinical and immunological features of myasthenia gravis and approaches to its therapy in the elderly / T.M. Alekseeva, V.D. Kosachev, A.N. Khalmurzina // Neuromuscular diseases. - 2016. - No. 6. - P.10-16.

2. Gusev E.I., Konovalov A.N., Skvortsova V.I. Neurology: National leadership / E.I. Gusev, A.N. Konovalov, V.I. Skvortsova. - M.: GEOTAR-Media, 2015. - 1064 p.

3. Kosachev V.D., Zhulev N.M., Nevzorova V.V. Features of the onset of myasthenia gravis in elderly and senile patients / V.D. Kosachev, N.M. Zhulev, V.V. Nevzorova // Russian family doctor. - 2010. - No. 3. - P.35-37.

4. Romanova T.V. Conservative treatment of myasthenia gravis in a myasthenic center /T.V. Romanova // Neurology, neuropsychiatry, psychosomatics. - 2013. - No. 5 (4). - S. 28-33.

5. Sanadze A.G. Myasthenia gravis and myasthenic syndromes /A.G. Sanadze. Moscow: LitTerra, 2012. 255 p.

6. Smolin A.I. Myasthenia gravis: variants of the clinical course, differentiated treatment and quality of life of patients: dis. … cand. honey. Sciences. - Irkutsk, 2015. - 127 p.

7. Shcherbakova N.I., Piradov M.A., Pavlova E.M., Ryabinkina Yu.V., Pirogov V.N., Gurkina G.T. Causes, risk factors, clinical predictors of the development of crises in patients with myasthenia gravis / N.I. Shcherbakova and [others] // Neurological journal. - 2013. - No. 2. - P. 11-19.

8. Melzer N., Ruck T., Fuhr P., Gold R., Hohlfeld R., Marx A. et al. Clinical features, pathogenesis, and treatment of myasthenia gravis: a supplement to the Guidelines of the German Neurological Society // Journal of Neurology. - 2016. - Vol. 263. - P. 1473-1494.

9. Strobel P., Storm-Mathisen A, Moritz R., Leite M.I., Willcox N., Chuang W.Y., Gold R., Nix W., Schalke B., Kiefer R., Muller-Hermelink H.K., Jaretzki I.A., Newsom -Davis J., Marx A. The aging and myasthenic thymus: a morphometric study validating a standard procedure in the histological workup of thymic specimens // Journal of Neuroimmunology. - 200. - Vol. 201–202. -P. 64-73.

10. Aarli J.A. Myasthenia gravis in the elderly: is it different? // Annals of the New York Academy of Sciences. - 2008. - Vol. 1132. - P. 238-243.

11. Liu Z., Lai Y., Yao S., Feng H., Zou J., Liu W., Lei Y., Zhu H., Cheng C. Clinical outcomes of thymectomy in myasthenia gravis patients with a history of crisis // World Journal of Surgery. - 2016. - Vol. 40(11). - P. 2681-2687.

12. WHO. World Health Organization Reproductive Health Library. 2003. Geneva, World Health Organization. – URL: http://apps.who.int/medicinedocs/en/d/Js4883e.

Myasthenia gravis is a chronic, rapidly progressive autoimmune disease characterized by impaired neuromuscular transmission due to the formation of autoantibodies to various autoantigenic epitopes of the peripheral neuromuscular apparatus, clinically manifested by weakness and pathological muscle fatigue.

If earlier myasthenia gravis was considered a rare disease with a prevalence of 0.5-5 cases per 100,000 people in the 60s of the twentieth century, now the disease is considered a fairly common occurrence with a prevalence of 4.8-5.0 to 17.5-20 ,3 per 100,000 people with an annual increase in the number of patients by 5-10% in all age groups. With myasthenia gravis, the ability to work is often impaired and often there is a disability of patients, a decrease in the quality of life, which leads to a high medical and social significance of the problem.

Among the factors predisposing the development of myasthenia gravis, the following are distinguished: traumatic situations, intense physical activity, overheating, past infections, surgical interventions, pregnancy and childbirth. The role of genetic factors is noted.

The development of myasthenia gravis can begin both in newborns and in the elderly. Currently, there are 2 main age peaks of the onset of the disease: early (from 20 to 40 years) and late (after 60 years). Currently, there has been a significant increase in the development of myasthenia gravis in the elderly. Among the sick women are 3 times more than men. However, in patients of the age group over 50, the ratio of women and men is almost equal - 1:0.85.

According to foreign literature, based on clinical, epidemiological, immunological, genetic studies, myasthenia gravis is divided into:

• eye;
• generalized with early onset (age of patients less than 45 years), often associated with thymic hyperplasia;
• generalized with a late onset (age of patients over 45 years), accompanied by age-related involution and atrophy of the thymus;
• thymoma-associated form.

It has been established that at the age of 60-70 years, the number of thymic myoid cells decreases and can reach a state close to deficiency.

Diagnosis of myasthenia gravis in patients of different age groups is carried out in the same way, however, in older people it is quite problematic due to the fact that muscle weakness at this age is regarded by doctors as a symptom of other diseases: motor neuron disease, stroke, polyneuropathy, chronic obstructive pulmonary disease, etc. In some cases, myasthenia can be combined with these pathologies, so there is a risk that the diagnosis of "myasthenia" will not be established. Moreover, as a rule, the development of myasthenia gravis is preceded by various kinds of pathological processes associated with somatic diseases.

The pathognomonic clinical and physiological markers of myasthenia gravis include:

1. Syndrome of muscle weakness and pathological muscle fatigue.
2. Dramatic reaction to acetylcholinesterase inhibitors.
3. Selective defeat of individual muscle groups.
4. relapsing current.
5. A positive result of the decrement test in electroneuromyography is the presence of a typical decrement response of the amplitude and / or area of ​​​​the M-response of the muscle action potential in the fifth, compared with the first stimulus, in response to superintense stimulation of the accessory or facial nerve at a frequency of 3 Hz before and after isometric tetanic contraction.

One of the important features of myasthenia, like other autoimmune diseases, is a chronic course with exacerbations and remissions. Perhaps the development of severe conditions - crises.

Crisis - a sudden rapid deterioration of neuromuscular transmission, leading to significant weakness of the bulbar and respiratory muscles. It is with them that the lethality of patients with myasthenia gravis is associated, which currently amounts to 4-8%.

1. Liu observed a malignant course in 1.3% of patients with tardive myasthenia gravis. According to A. Storm-Mathisen, mortality in people over 60 reaches 48.3%. Danger to the life of the patient occurs during the development of a myasthenic crisis, which is most often associated with the progression of the disease under the influence of adverse factors (infections, operations) or caused by iatrogenesis (cancellation of drugs, the appointment of an inadequate dose of drugs or drugs that are contraindicated in case of myasthenia). With an increase in generalized muscle weakness, there is a threat of respiratory arrest and the development of acute heart failure. In the pathogenesis of myasthenic crisis, a key role is played by a decrease in the density of cholinergic receptors in the postsynaptic membrane.

With an overdose of anticholinesterase drugs, a cholinergic crisis develops. Outwardly, it resembles myasthenic, but with it muscarine- and nicotine-like effects are observed, due to excessive activation of nicotinic and muscarinic cholinergic receptors.

With a mixed myasthenic crisis, there are 2 components - myasthenic and cholinergic, the tactics of managing the patient depend on the predominance of one or the other.

Target: to analyze the course of myasthenic crisis with late debut of myasthenia gravis.

Materials and methods. We observed 13 cases of myasthenic crisis. All patients with a crisis were divided into 2 groups. The first group included patients at a young age up to 35 years - 4 people. The second group included elderly patients (60 years and older) - 9 people.

All patients underwent a neurological examination, multislice computed tomography of the mediastinal organs and an ENMG decrement test.

results

In the period from 2013 to 2015 in the State Budgetary Institution of Health of the Nizhny Novgorod Regional Clinical Hospital named after I.I. ON THE. Semashko, 13 patients with a crisis were registered. All patients had a generalized form of myasthenia gravis with severe respiratory and bulbar disorders.

Among the observed patients, persons aged 60-80 years predominated - 9 people, and only in 4 people, in 1/3 of the observations - myasthenic crisis developed at the age of 19-35 years. There were no patients with myasthenic crisis aged 35 to 60 years. Among the patients, women predominated - 11 people.

The duration of the disease in all patients was 5.77 ± 1.84 years, among young patients 9 ± 5.1 years; in patients aged 60 years and older - 4.33±1.46 years.

In 2 people, a myasthenic crisis was observed, which was manifested by severe bulbar disorders, increasing respiratory failure, rapidly increasing weakness of the skeletal muscles, which led to the hospitalization of patients in the intensive care unit and their transfer to artificial lung ventilation.

In 2 people, a cholinergic crisis was observed, which was associated with an overdose of anticholinesterase drugs. Outwardly, the cholinergic crisis resembles a myasthenic crisis and is characterized by deterioration, generalization of muscle weakness, the appearance or aggravation of bulbar disorders, and respiratory disorders. The muscles of the face, the chewing muscles, and the muscles of the shoulder girdle are always severely affected. The muscles of the eyes and pelvic girdle are most resistant to overdose. In contrast to the myasthenic crisis, in this case, there are distinct vegetative disorders characteristic of muscarinic and nicotinic effects: increased salivation and separation of bronchial mucus, sweating, violent intestinal motility, diffuse abdominal pain, often profuse loose stools, frequent urination, repeated vomiting may occur . In addition, constriction of the pupils, bradycardia, hypotension, widespread fasciculations in the muscles, sometimes convulsions, and a feeling of spasm in the throat are characteristic. Loss of consciousness, involuntary urination may develop.

The remaining 9 people had a mixed crisis, which is the most common in clinical practice. It combines all the clinical features of myasthenic and cholinergic crises described above. This is the most severe variant of vital disorders in patients with myasthenia gravis. A feature of the distribution of movement disorders during a mixed crisis is that with complete functional failure of the cranio-bulbar and respiratory muscles, the strength of the muscles of the arms and legs can be slightly reduced. In addition, attention is drawn to the unequal reversibility of movement disorders in different muscle groups while taking anticholinesterase drugs. It is this type of crisis that most often leads to death in patients with myasthenia gravis.

The table shows a comparative characteristic of young and elderly patients hospitalized for myasthenic crisis. The average age of myasthenia onset in the age group of 60-80 years was 64.5±7.7 years, the average duration of the disease was 3.7±0.8 years, in one patient the disease debuted with a myasthenic crisis at the age of 60 years.

A provoking factor in the development of a crisis in six out of thirteen people was an acute respiratory viral disease, five out of six people were taking anticholinesterase drugs uncontrollably; in three patients, exacerbation was provoked by surgical treatment (caesarean section, hip arthroplasty), in three people - psycho-emotional stressful situations, while two independently increased the dose of anticholinesterase drugs, in one patient, decompensation was caused by physical activity.

The common provoking factors for the development of myasthenic crisis for both age groups were acute respiratory viral diseases and stressful conditions. However, in the group of elderly patients, the predominant provoking factor was an uncontrolled independent increase in the frequency of administration and dosage of anticholinesterase drugs. Thus, seven out of nine elderly patients independently increased the dose of anticholinesterase drugs to 6-8 tablets per day.

The reasons that prompt patients to increase the daily dose of anticholinesterase drugs need further study. This may be due to a deterioration in general well-being, both against the background of an acute respiratory disease, and due to comorbidities in old age. The low compliance of these patients in some cases is due to the presence of a cognitive defect caused by age-related changes or resulting from cerebrovascular and neurodegenerative diseases associated with old age.

The problem of insufficient adherence of patients to treatment is relevant for many chronic diseases. So, up to 50% of patients with arterial hypertension, bronchial asthma, atherosclerosis with hyperlipidemia, diabetes mellitus, epilepsy and other diseases independently interrupt the treatment prescribed by the doctor. It is believed that low compliance is the main reason for the decrease in the severity of the therapeutic effect of drugs with proven efficacy. The absence or decrease in compliance significantly increases the likelihood of developing complications of the underlying disease. This is one of the significant factors leading to a decrease in the quality of life of patients and an increase in the cost of treatment. Unfortunately, patients with myasthenia gravis are not a happy exception in this regard, despite the severity of the pathology.

Table 1

Comparative characteristics of patients with myasthenic crisis

Patients with late onset of myasthenia had a mixed-type crisis with a predominance of the cholinergic component, which manifested itself as increased salivation, diarrhea, abdominal pain, sweating, seizures, and fascicular twitches. The cholinergic nature of the crisis was a natural consequence of the previous overdose of anticholinergic drugs.

Young patients developed a myasthenic crisis with a characteristic clinical picture.

All patients with a developed crisis were admitted to the intensive care unit, where they underwent the following set of therapeutic measures:

• adequate breathing with artificial lung ventilation;
• setting a nasogastric tube to ensure swallowing;
• withdrawal of anticholinesterase drugs;
• pulse therapy with metipred at a dose of 1000 mg IV drip 1 time per day for 5 days, followed by a transition to oral glucocorticosteroid therapy with the calculation of an individual dose of the drug;
• plasmapheresis 3-5 procedures.

The period of withdrawal of anticholinergic drugs in elderly patients was longer (5 days) than in young patients (3 days), which was associated with the nature of the crisis. It is known that cholinergic and mixed crises, which in our observational study were more common in elderly patients, have a more severe and protracted course compared to myasthenic crisis. Accordingly, the period of respiratory support was also longer in patients of the older age group.

Conclusion. Thus, a crisis is a fairly common complication of myasthenia gravis in patients with a late onset of the disease. According to our data, the crisis course of myasthenia gravis was more common in elderly patients than in young patients. At the same time, a feature of the course of myasthenic crisis in the elderly is the predominance of the cholinergic component, which requires a longer withdrawal of anticholinesterase drugs. Independent uncontrolled increase in daily dosages of anticholinesterase drugs by patients is an important provoking factor in the development of crises in patients with a late onset of the disease, which requires more careful dynamic monitoring of the condition of patients, additional monitoring of the clinical manifestations of myasthenia gravis, and extreme caution when increasing the dose of anticholinesterase drugs.

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Myasthenia gravis is a fairly rare pathology of an autoimmune nature. The officially registered cases of this violation are about 0.01%.

Usually the disease occurs in people aged 15 to 45 years, but the largest number of cases of its development occurs at the age of 20-30 years, and the smallest - in childhood.

With the gradual development of the pathological condition, the transmission of nerve impulses to muscle tissues is blocked, which leads to their degenerative changes.

There are 2 forms of myasthenia - ocular and generalized. In the first variant, the muscles of the eyeball suffer more from the disease, and in the second, the disease affects the entire body equally.

The worst type of pathology development is myasthenic crisis, which requires urgent intervention of specialists.

To date, there is no proven information about the origin of such a disease as myasthenia gravis.

The vast majority of specialists are inclined to the hereditary theory of the origin of the pathology, since many of the patients with myasthenia gravis indicated that there had already been cases of such a disease in the family.

The etiology of the process lies in the violation of immune processes, that is, pathological changes in the thymus () - the body begins to produce antibodies that block the receptors of the postsynaptic membrane with its subsequent destruction.

When considering myasthenia gravis as an independent disease, there are a number of reasons that can provoke the body to produce antibodies:

• frequent stressful situations;
• depressive states;
• infectious impact;
• immune pathologies.

When myasthenia gravis is one of a set of diseases, it is considered as a syndrome. Common comorbidities are:

• thymus hyperplasia;
• amyotrophic syndrome (lateral);
• malignant neoplasms (more often - lung, testicle, mammary glands);
• systemic pathologies of connective tissues.

There are no separate, specific for myasthenia gravis, changes in the central nervous system. With the gradual development of the pathology, there are risks of weakening the muscle fibers to the state of disability or the occurrence of a myasthenic crisis.

myasthenic crisis

Myasthenic crisis is the most severe manifestation of pathology.

There is a severe blocking of the conduction of neuromuscular impulses at the heart of the respiratory system, with the development of apnea and bulbar disorders. With myasthenia gravis, a crisis can be triggered by such reasons:

• active development of pathology;
• exacerbation of a secondary disease;
• infectious damage to the body;
• stress impact;
• skipping medications;
• excess or underestimation of dosages;
• the use of contraindicated drugs.

At the initial stage of the myasthenic crisis, the patient's condition is expressed as follows:

The latter occurs due to a significant relaxation of the sphincters in the patient's body. If the heart muscle is affected, acute heart failure occurs.

Symptomatic signs increase over 20-30 minutes, in the process, violations of the central blood supply to the brain may occur with the onset of its hypoxia, which can lead to loss of consciousness and death of the patient.

Diagnosis of myasthenia gravis

Diagnosis of myasthenia gravis has some difficulties, due to the ambiguity of the origin of the pathological condition at the time of detection of symptomatic signs.

The best diagnostic option is to identify the following changes:

• lymphocytosis;
• decrease in biopotentials (electroexcitability of muscle tissues);
• enlargement of the thymus shadow.

One of the most accurate research methods is pneumomediastinotomography, but the technique requires invasive intervention.

To date, experts have abandoned this practice in favor of the use of computed tomography, which has a sufficient number of advantages:

• extended information content;
• patient safety;
• high reliability.

The number of reliable results in the study of the thymus on CT is about 92%, with a small increase in the thymus.

In the case of a neglected development of a pathological condition, diagnosis is simplified.

In the process of making a diagnosis, a proserin test is used.

Some experts argue that when using this research technique in certain patients, there was a weakening of the symptoms inherent in myasthenia gravis and after surgical treatment (in this variant of removal of the thymus), all symptomatic manifestations of the disease disappeared.

In the absence of changes, the complete disappearance of signs of the disease is not observed.

In some embodiments, the pathological condition progresses in the absence of secondary pathologies and unchanged thymus parameters.

This variant of the pathological disorder is the persistent thymus, and it requires surgical intervention, excluding the presence of direct contraindications.

Also, there is a need for additional differentiation of the diagnosis with myasthenic syndrome, which has a different origin, but is characterized by a similar symptomatic picture.

This syndrome occurs in patients suffering from:

• encephalitis;
• amyotrophic lateral sclerosis;
• multiple sclerosis;
• certain types of hormone-producing tumors.

In cases where myasthenia gravis is a consequence of development, an important role in diagnosing a pathological condition plays an immunohistochemical study of the protein spectrum.

Due to this analysis, it becomes possible to determine the type of tumor process, the presence of metastases and its effect on the body.

Treatment

Conducting conservative treatment of myasthenia gravis is not always possible.

The relief of a pathological disorder due to drugs is allowed only with a mild course of the disease in localized forms. As part of therapeutic treatment, the following are used:

1. Anticholinesterase agents, among which the most widespread are: Galantamine, Oksazil, Kalimin, Prozerin. In addition to them, potassium salts are used (give a strengthening effect).
2. "Pulse therapy" - the use of Prednisolone in high dosages. Start using the drug with 1-2 thousand mg with a gradual decrease.
3. Immunosuppressants (pharmacological agents for artificially weakening the immune system) - Cyclophosphamide, Azothioprine, Cyclosporine.
4. In severe myasthenia gravis and the impossibility of surgical treatment, an individually selected version of HRT and cytostatics (drugs that inhibit the development of tumors) are used.

With generalized myasthenia gravis, there is a need for thymectomy, since all types of the disease have a direct relationship with the thymus.

Thymectomy as a method of treating myasthenia gravis was first used in 1939 and has been recognized as the main method of treatment since about the 50s of the 20th century.

The absolute indications for an operation to remove the thymus are as follows:

1. True myasthenia. First of all, a generalized form of the disease, as well as musculoskeletal and pharyngeal-facial with a moderate and severe type of course.
2. Myasthenia gravis against the background of a developing neoplasm in the thymus gland. Both malignant and benign tumors are considered.
3. In cases where the pathology leads to a gradual violation of the functions of swallowing and breathing, as it carries increased risks to the patient's life and causes particular discomfort.
4. Active progression of myasthenia gravis, regardless of ongoing treatment with HRT and other pharmacological agents.

As relative indications, the following are distinguished:

• facilitated course of the disease;
• local forms of myasthenia gravis;
• disease duration over 5 years.

Among the contraindications to the operation of the thymus gland are:

• myasthenic syndrome;
• inoperability of the tumor process;
• the patient's age is over 65 years;
• severe secondary pathologies (usually cardiovascular).

In any case, the decision on the possibility of surgical relief of the disease requires a completely individual approach.

This is due to the multiplicity of factors affecting the course of the disease. Sometimes, with mild forms of myasthenia gravis, an operation may be prescribed, for example:

1. The diagnosis made corresponds to an uncomplicated localized form of myasthenia gravis and does not pose a serious danger to the patient.
2. Anticholinesterase therapy was prescribed to correct the condition and relieve the main symptoms of the pathology.
3. For a long time, the prescribed therapy does not help, and the symptoms of the disease began to progress and myasthenia gravis becomes generalized.
4. The doctor decides to operate on the thymus, since the disease poses an increased threat to the health and life of the patient.

In any case, there is no direct dependence on the presence of tumor neoplasms or in myasthenia gravis as a disease.

Therefore, each individual case requires careful diagnosis and multiple tests to determine the patient's condition.

To reduce the risks for the patient, with the possible onset of a myasthenic crisis, it is recommended to be constantly accompanied by a loved one, as emergency care may be required.