Pannus in dogs treatment regimen. Chronic superficial keratitis (Pannus). Corneal lesion in pannus

pannus (chronic superficial keratitis, shepherd pannus, Uberreiter's syndrome) is an inflammation of the cornea characterized by infiltration of the cornea with granulation tissue containing lymphocytes and plasma cells, superficial vascularization and pigmentation of the cornea.

This condition affects both eyes, the lesion begins near the limbus more often from the lateral edge (Figure 1), and then the central zone of the cornea is also involved in the process, if left untreated, the disease progresses and can lead to if it affects the entire area of the cornea (Figure 2).

Figure 1. Shepherd dog pannus (characteristic lateral corneal lesion) and third eyelid plasmoma

Figure 2. Shepherd dog pannus (the entire central part of the cornea is affected)

Changes in the cornea are striking clinical signs, along with them, the animal has blepharospasm, excessive secretion of mucus from the conjunctival sac, and possibly the occurrence of secondary purulent conjunctivitis.

Almost always, along with pannus, an animal observes a similar process in the third century - plasmoma.

Plasma

Plasma - infiltration of the third eyelid with plasma cells, characterized by depigmentation and thickening of the third eyelid, the formation of follicles on its surface, this condition also affects both eyes (Figure 1, 3).

Figure 3. Plasmoma of the third eyelid in a shepherd dog (the third eyelid is edematous, its edge is depigmented)

Pannus and plasmoma are found mainly in German shepherds, their mestizos, cases are also described in Greyhounds, Greyhounds, Doberman Pinscher. The disease is considered immune-mediated (that is, the animal's immune system does not adequately respond to its own tissues), predisposing factors, in addition to the breed, consider habitat conditions: high mountains and excessive amounts of ultraviolet radiation.

Typical clinical signs are sufficient to diagnose pannus and plasmama, however, the veterinary ophthalmologist must differentiate these diseases from others using slit lamp examination, the Schirmer test and other diagnostic tests, in some cases cytological examination from the surface of the affected tissues may be required for clarification of the diagnosis.

After the diagnosis is determined, treatment begins. Several groups of drugs have been described for the therapeutic treatment of pannus and plasmoma.

These include corticosteroid eye drops, subconjunctival injections of corticosteroid hormones, cyclosporine eye drops, but tacrolimus drops or ointment provide the best results, have fewer side effects, and are well tolerated by patients.

It is necessary to use drugs in the conjunctival sac with pannus and plasmoma constantly, the frequency of use is selected individually. The use of drugs allows you to contain the signs of the disease and keep the animal comfortable for the eyes and vision (Figure 4). It is recommended to avoid exposure to sunlight

Pannus and plasmoma

pannus chronic superficial vascular keratitis) is a lesion of the limbus and cornea of the eye resulting from a local chronic inflammatory process. The infiltrate formed under the corneal epithelium is replaced by scar tissue, which leads to a significant decrease in vision.

The condition where a similar immune response affects the conjunctiva and the third eyelid is called plasma(plasmatic lymphatic conjunctivitis of the third eyelid). The plasmama is less threatening to visual loss, but causes more ocular discomfort and is often more resistant to pannus therapy.

Etiology.

To date, there is no doubt that pannus is an autoimmune disease. This means that the leading role in the occurrence of this disease is played by the immune system, which recognizes all subcellular changes in the cornea as pathological and tries to neutralize the process. Thus, the immune system considers its own cornea as a foreign tissue and tries to reject it.

The first reports of pannus appeared in areas with high ultraviolet activity (in Austria and the US state of Colorado). Today, the disease is registered in all countries of the world, and it is no secret to anyone that cases of pannus in areas with increased ultraviolet activity are more difficult and less amenable to therapy. This allows us to conclude that ultraviolet rays play an important role in the occurrence of this disease. This phenomenon is due to the fact that exposure to ultraviolet radiation on the cornea accelerates the rate of metabolic processes in the latter. And the more active the metabolic processes, the more actively the immune system tries to reject it. Given that the ozone layer of the atmosphere is constantly thinning and the natural shield from ultraviolet radiation is disappearing, it is not difficult to imagine why pannus has become ubiquitous.

The genetic and breed predisposition of dogs to pannus has also been noted. This pathology is most common in dogs of such breeds as the German Shepherd, Black Terrier and Giant Schnauzer, and is much less common in dogs of other breeds.

Symptoms.

Diagnosing this disease is usually not difficult. The clinical manifestations of pannus are quite characteristic: significant infiltration of the cornea and ingrowth of vessels, as a result of which the affected areas of the cornea become similar to granulation tissue. Pannus usually begins in the upper outer or lower inner quadrants, but the entire cornea may soon be affected. Due to the replacement of the infiltrate formed under the corneal epithelium with granulation tissue, visual acuity decreases (up to complete loss of vision). In the future, with a chronic course, the affected areas become black due to the deposition of pigment in them.

Moreover, pannus is accompanied by a pronounced corneal syndrome: lacrimation, photophobia, moderate blepharospasm.

Diagnostics.

Diagnosis of pannus and plasmoma requires examination of the eye with focal illumination, biomicroscopy, corneal fluorescein staining, and cytology of the cornea and conjunctiva. It is worth noting that only a cytological examination allows you to accurately diagnose and conduct high-quality treatment.

Treatment of this pathology should be regular, and it requires the owners to accurately perform all manipulations. Sometimes lifelong therapy with special drugs is needed.

Immunosuppressive drugs are used to treat pannus and plasmatic lymphatic conjunctivitis of the third eyelid.

In the initial stages, glucocorticoid therapy can be quite effective, although in some cases it is ineffective. Moreover, prolonged therapy with glucocorticoids leads to an increase in intraocular pressure.

Of the immunosuppressive drugs, Cyclosporine A is being actively introduced into ophthalmological practice. The main dosage forms of cyclosporine in our country are capsules and oral solution (Sandimmun, Sandoz, Neoral, Gengraf). However, when used systemically, these drugs exhibit some nephro- and hepatotoxicity. In ophthalmology, the use of this drug in the ophthalmic form is recommended, since in this case it will not have a systemic effect, and its side effect will not appear.

Cyclosporine in the form of an eye ointment has long been used by Western veterinary ophthalmologists. This ointment is called "Optimmune" (Optimmune). It is very convenient and easy to use. In the State Scientific Center for Antibiotics of the Russian Federation some time ago, liposomal eye drops of cyclosporine (0.2%) - "Cyclolip" were created, which have successfully proven themselves in the treatment of autoimmune eye diseases. But, unfortunately, the release of this drug is currently suspended.

Some veterinarians use a 1-2% oil solution of cyclosporine, prepared independently from olive, grain and vegetable oils, however, the use of these solutions is often accompanied by allergic reactions.

For 3 years, we conducted a study of drops, which we ourselves produced from an oral suspension of the drug "Cyclosporine Neoral" (2% oil-based solution). Despite various formulations using various types of medical oils, we have not been able to create a drug similar to Optimmun.

In addition to the use of immunosuppressive drugs, therapy for pannus and plasmoma should include protecting the dog's eyes from ultraviolet radiation. For this purpose, special glasses of various sizes are used. In the absence of the possibility of purchasing glasses, animal walks at dusk or at night, when the intensity of ultraviolet radiation decreases, can be recommended.

It should be noted that the above-described cyclosporine therapy usually gives good results in pannus, and is less effective in third eyelid plasmama.

Veterinarian - ophthalmologist

Konstantinovsky Alexander Andreevich

Chronic keratoconjunctivitis due to autoimmune disorders in dogs is called pannus. The disease affects the limbus and cornea. The infiltrate formed over time under the cornea is replaced by scar tissue, which leads to deterioration of vision up to its loss.

Pannus in dogs causes

The exact etiology is unknown. Presumably the influence of hereditary factors, since the disease is characteristic of certain breeds, which include:

German and East European Shepherds (also their mestizos).
Husky.
Dachshunds.

It is much less common in other breeds.

It has been proven that pannus in dogs develops under the influence of ultraviolet radiation, since the disease is most often diagnosed in areas with increased ultraviolet activity.

Pannus eye mechanism of development

The autoimmune nature of the pathology is beyond doubt. The main role in the appearance and development is played by the immune system, which recognizes subcellular changes in the cornea as foreign. Further, protective mechanisms try to neutralize pathological processes, leading to rejection of the outer shell of the eye.

The influence of ultraviolet leads to an acceleration of metabolic processes in the cornea, which forces the immune system to respond more actively to “foreign” tissues. Therefore, the pannus of the eye has become so widespread in regions with increased exposure to ultraviolet radiation.

Pannus cornea symptoms

At the onset of the disease, due to the proliferation of epithelial cells, infiltrates of plasma cells and lymphocytes form in the stroma. As the cornea progresses, it becomes neovascularized and becomes cloudy. Without treatment, immune cells that enter the cornea from the formed vessels cause its rejection.

Most often pannus of the cornea is manifested by the following signs:

Dry eye syndrome.
Redness.
Swelling caused by the process of neovascularization.
Blurred eye.
Corneal syndrome (blepharospasm, lacrimation, photophobia).
Outwardly, bumpy pink-red growths are visible interspersed with brown pigmentation.

The disease affects both eyes, but in each of them the rate of development may differ. Typically, the initial manifestations are seen in the temporal quadrant, eventually moving to the entire cornea.

Diagnosis of pannus

Diagnosis is easy in most cases. In addition to detecting a characteristic clinical picture, finding out the region of residence of the animal and its breed, a number of diagnostic procedures are required, which include:

Inspection using focal illumination.
biomicroscopy. It is carried out to more accurately characterize the ongoing changes.
Cytological examination of scrapings from the cornea, conjunctiva. Only this method allows you to confirm the diagnosis of pannus. In most cases, scrapings show lymphocytes and plasma cells, which have completely replaced normal cells.
For differential diagnosis, fluorescein staining is sometimes performed. It should be understood that this method can confuse the veterinarian, since in some cases a color characteristic of a corneal ulcer is detected. This leads to the beginning of the wrong treatment, which does not work.

Only an integrated approach allows us to confirm the presence of an autoimmune process in the cornea and prescribe the correct treatment.

Pannus in dogs treatment

Autoimmune diseases cannot be completely cured. The main method of therapy is symptomatic. If pannus is diagnosed in dogs, treatment must be carried out in a course, for life. The veterinarian develops a scheme according to which medications are taken during periods of exacerbations, and preventive measures for the period of remission.

The goal of treatment is:

Reduction of the affected area.
Prevention of the transition of the disease to neighboring areas, prevention of blindness.
Decreased aggressiveness of the immune system.

At the initial stages, it is possible to prescribe glucocorticosteroids, but long-term use of drugs in this group often causes an increase in intraocular pressure. The main drugs are immunosuppressants, among which the most common is Cyclosporine A. It is available as eye drops, ointment, and oral solution. The latter option is the least preferred due to possible complications from the liver and kidneys. The use of local forms of Cyclosporine prevents side effects while maintaining a local effect.

Therapy begins with aggressive doses, which are reduced as symptoms regress. Further maintenance doses are prescribed.

There is a surgical method of correction - superficial keratectomy, but it is rarely used due to frequent postoperative complications.

To reduce the effect of ultraviolet radiation on the cornea, your veterinarian may recommend wearing special sunglasses for animals.

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Definitions

Pannus is a progressive, bilateral inflammatory disease of the cornea in dogs.

Synonyms: Chronic superficial keratitis, German shepherd pannus, degenerative pannus, Uberreiter's syndrome.

Etiopathogenesis

Presumably an immune-mediated process with a genetic basis, corneal antigens are modified by various environmental factors (usually ultraviolet light) and are attacked by the immune system.

Clinical signs

Breed predisposition - German Shepherd (primarily), other herding dogs (ex. Australian Shepherd, Border Collie), Golden Retriever, Greyhound, Rottweiler. The disease is likely to develop in any breed of dog.

The characteristic initial localization of the lesion is the lower temporal and lower nasal region of the cornea, with a severe course, progress is likely with the involvement of the entire surface of the cornea. The development of an irregularly shaped infiltrate from red to gray is characteristic. The lesions are bilateral and symmetrical.

Quite often there is an irregular thickening and local depigmentation of the third eyelid.

Cytological examination of the cornea is characterized by the accumulation of lymphocytes, plasmasites and macrophages.

Lesions usually do not stain with fluorescein.

Diagnosis

Diagnosis is based on characteristic clinical signs in predisposed breeds, as well as by exclusion of other diseases with a similar clinical picture.

Differential Diagnosis
.
Granulating corneal tissues developing during the healing process.
Squamous cell carcinoma of the cornea (very rare).

Treatment

The goals of treatment are to achieve control of the disease, but not a complete cure. It is important to inform the owner of lifelong therapy and the likely progress of the disease. For treatment, various local immunosuppressive drugs are more often used.

Initially, therapy is carried out with solutions or ointments with corticosteroids (ex. 0.1% dexamethasone or 1% prednisolone). The multiplicity is selected from the severity of the condition, at the beginning 3-4 times a day, and then depending on the response to therapy. In severe cases, subconjunctival corticosteroids are likely. In long-term treatment, dogs should be monitored for ocular infections and corneal ulcers.

Cilosporin in the form of an ointment can be used both separately and in combination with corticosteroids. Frequency rate of introduction - 2 times a day.

If corticosteroids and cyclosporine are ineffective, radiation therapy is likely.

During therapy, worsening of symptoms should be expected during periods of increased solar activity; for this period, an increase in the frequency of drug administration is likely.

Forecasts

The age of onset significantly affects the prognosis of the disease, so when the disease occurs at a young age (1-5 years), a severe course with pronounced progress is characteristic, when the disease occurs at a later age, a mild course is characteristic, adequately responding to therapy.

Photo 1. Pannus in a 5 year old Labrador. Initial treatment without treatment.

Valery Shubin, veterinarian, Balakovo.

Pannus - the disease is mainly recorded in German shepherds, but also occurs in other breeds of dogs. It is manifested by a change in the cornea: the growth of blood vessels and scar tissue. This process usually begins in the lateral or ventral quadrant of the cornea, then progresses to the entire surface of the cornea, which can lead to blindness. The cornea turns black due to the accumulation of pigment.

The mainstream view is that pannus is an immune-mediated disease. Such cellular changes in the cornea begin when the cornea is recognized (perceived) by the body and the immune system as a foreign tissue or graft. It is assumed that German Shepherds are predisposed to this disease, but an important factor influencing the development of the disease is ultraviolet radiation. Pannus was first discovered in Austria and the USA, Colorado, both areas are highly elevated. Today, pannus is reported worldwide, however, the causes are still not fully identified, and it is very difficult to treat, especially in high altitude areas, which confirms the UV theory.

Treatment is aimed at reducing the immune response locally. Steroids (dexamethasone and prednisolone) are used, which have anti-inflammatory and immunosuppressive effects, cyclosporine is a drug with an immunosuppressive effect. Cyclosporine is used topically as monotherapy or in combination with steroids, which improves the outcome of treatment, compared with the use of steroids alone.

Cyclosporine has been used to treat pannus by veterinarians for about 12 years. A 1% or 2% solution is used, based on olive, corn or vegetable oil. About 5 years ago they started using 0.2% cyclosporine in the form of an eye ointment called "optimmun". Now it is successfully used to treat other eye diseases, such as: "dry eye syndrome". In the case of pannus, it was concluded that a 0.2% solution was less effective than a 1%. After treatment, active vascularization and granulation may disappear, but scar tissue and pigment dissolve very slowly, or do not change at all.

Recently, cyclosporine Neoral was released in the form of a microemulsion. The microemulsion can be diluted with other solutions than just oil. This is an advantage over oil solutions, as the oil can irritate the skin around the eyes, and can also stain furniture (when the animal rubs its muzzle, for example, on a sofa). Cyclosporine can be mixed with aqueous solutions of dexamethasone or prednisolone, thereby increasing the effect of treatment. Initially, the new solution caused irritation in some dogs, but after a few weeks of application, this disappeared.

As a rule, pannus accompanies a disease such as plasmoma - this is an increased immune response at the border of the third eyelid and conjunctiva and is manifested by plasmatic lymphoid conjunctivitis. This condition is also more common in German Shepherds. Compared to pannus, plasmamata are less likely to affect vision, cause discomfort, and are less treatable.

Reducing the effect of UV radiation also helps to reduce the rate of pannus development. Keeping dogs indoors on sunny days or using dog-specific sunglasses reduces the likelihood of pannus occurring and developing.