PANNUS IN THE GERMAN SHEPHERD DOG

The more that I think I know about the breed, the more I realize that I don’t. This is just one of the things that I didn’t know that the German Shepherd Dog can be affected by. I never even heard of this disease before.

German Shepherd Dog Keratitis [pannus], medical name: keratitis superficialis vasulosa pannosa pigmentosa chronica, is a chronic inflammation of the corneal surface and, in most cases, of the conjunctiva of the eye. The reason it is called German Shepherd Dog Keratitis is because the disease is found predominantly in German Shepherds and is only rarely seen in other breeds.

Pannus is a condition where your dogs’ immune system attacks the cornea. Symptoms include changes in color and the appearance of red blood vessels. While there is no cure for the syndrome, it can be controlled for the life of your dog. Failure to treat the condition can result in blindness.

It is normally seen in dogs between the ages of three and five. It first appears in the outer regions of the cornea and, in almost all cases, affects both eyes simultaneously.

The cornea is a membrane that covers the colored part and white part of the eye. Canine keratitis is a syndrome where the cornea becomes inflamed and discolored (corneal pigmentation). Pannus causes tissue to accumulate on the surface of the eye and cholesterol to form inside the cornea.

The cause of Pannus is not well understood, but several factors are involved. The breed incidence suggests a heritable predisposition. Additionally, UV (ultraviolet) radiation plays an important role as an inciting and propagating factor. Dogs living at high altitudes and low altitudes are more severely affected. Also, autoimmune factors and possibly genetics play a part.

Initially, redness and brown pigment may be seen in the conjunctiva (white tissue of the eye). White infiltrates made up of inflammatory cells then invade the clear cornea. Next blood vessels invade the cornea. Finally pink connective tissue grows into the cornea and later becomes brown. In a small number of cases, two other symptoms may occur either alone or together. A thickening, redness, de-pigmentation and lumpiness of the third eyelid may occur. This is called a plasmoma. The other condition which may occur is chronic, erosive ulceration of the lower eyelid near the inner and outer corners of the eye. Pannus is uncomfortable to the dog. When treated adequately, your dog can be free of this irritation even though the corneas may not clear up completely.

What is the treatment for Pannus? Despite intensive research efforts, no permanent cure exists for this disease. However, in the vast majority of cases, the diseases progress can be halted and the problem kept stable. In other cases, Pannus may be reversed and the corneas will clear. This is most probable if therapy is instituted early during the disease. The inflammatory cell infiltrate and blood vessel invasion are generally reversible with therapy. The connective tissue infiltration and pigment deposits are often not reversible once they have occurred.

There are four types of therapy:

1. Corticosteroid (cortisone) therapy. This is the main line of defense against progression of the disease and in most cases is effective. If the pannus is severe, cortisone may be administered by injections under the white of the eye. In all cases drops containing cortisone must be applied to the eye many times a day. Treatment must be kept up for the rest of the pet¹s life. Even short periods of interrupted treatment, i.e., 2-to-4 weeks, may cause severe relapse with worsening of the patient's vision. The main side-effect of prolonged corticosteroid therapy is the adverse effect on corneal wound healing. Microscopic wounds of the outer layer of the cornea often occur. In a normal eye the cornea heals rapidly. If corticosteroid medications are being applied, minor wounds worsen leading to serious corneal ulceration. The main sign seen in patients with ulceration is pain. Therefore, should any patient on cortisone therapy show signs of pain, such as holding the eye shut or pawing at the eye, it is important that the medication be stopped and the doctor consulted immediately.

2. Cyclosporine is a new medication in the war on pannus. It does work on pannus and doesn't have the side effects of corticosteroids. Unfortunately, cyclosporine doesn't work as quickly and it is usually necessary to continue it twice daily for the rest of the patient¹s life. Often, we will initially prescribe corticosteroids to be used in addition to the cyclosporine. When used together, greater improvements are seen without the side effects associated with high levels of corticosteroids.

3. Surgery may be used when medication does not completely clear the pannus from the cornea. A 'peeling' of the cornea may be required to restore vision in eyes that are severely scarred and pigmented. Unfortunately, treatment is required following surgery to prevent the pannus from recurring as the cornea heals. This method is only used if medication doesn't work.

4. Beta-irradiation may be used when medication and surgery prove insufficient. This will not be recommended unless all else fails.

Although Pannus can be a condition that requires life long treatment, with the correct diagnosis and early treatment, the dog's vision can be maintained.


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My rating: Learning and educating yourself on the diseases of the German Shepherd Dog: (4)