Degeneration of the Cerebellum in Cats

Cats with cerebellar abiotrophy tend to have difficulty with their sense of space and distance and experience a loss of balance and coordination. Vision and mental ability are not affected, and in most cases, the condition is unlikely to cause an early death. Although there is no cure for cerebellar abiotrophy, many cats learn how to adapt to it, resulting in the reduction of noticeable symptoms over time.

Cerebellar abiotrophy is a rare brain disease that causes the cells of the cerebellum to die. Symptoms are very similar to cerebellar hypoplasia. The primary difference is that kittens with cerebellar hypoplasia are born with an underdeveloped cerebellum while those with cerebellar abiotrophy are born with a normal brain that eventually begins to deteriorate. In both cases, kittens display neurological symptoms and may be described as “wobbly.” While cerebellar hypoplasia occurs in-utero, often as the result of exposure to the distemper virus, cerebellar abiotrophy typically begins shortly after birth. Symptoms are usually noticeable by the time the kitten has reached six months of age. In rare cases, the cells die off more slowly and symptoms are not noticeable until later in life.

Cerebellar hypoplasia and cerebellar abiotrophy share many common symptoms including:

• Wide-leg stance
• Abnormal posturing
• Swaying
• Muscle tremors
• Head tilt
• Lack of coordination
• Falling
• Weakness
• Behavioral changes and depression
• Lack of menace response (blink reflex)

Additional symptoms that tend to be specific to cerebellar abiotrophy include:

• Hyperactivity
• Stiff or high-stepping gait
• Jerky head-bob
• Walking on knuckles
• Poor depth perception
• Rapid eye movement
• Collapse

The exact cause of cerebellar abiotropy is unknown. In rare cases, the cerebellum may be damaged from a brain tumor or infection. More commonly, it is thought to be linked to a genetic predisposition transmitted as an autosomal recessive trait. This means that the abnormal gene must be present in both parents for the trait to be passed on to kittens. If a cat inherits only one set of the gene it will not display any symptoms. It will, however, be a carrier and may pass the condition on the future generations. Cats with cerebellar abiotrophy should be spayed or neutered as early as possible. Siamese, Persian, and domestic shorthair cats may be more likely to be affected by the condition. For these breeds, genetic testing should be considered prior to any planned breeding.

Definitive diagnosis of cerebellar abiotrophy can be difficult. The vet may order an MRI to observe the size of the cerebellum and routine blood, urine, and electrolyte tests to rule out other conditions that cause similar symptoms. A cerebrospinal fluid analysis may be ordered, but depending on the cause of the condition this may or may not assist in diagnosis. If a cat displays several of the most common symptoms and other neurological causes have been ruled out, a positive diagnosis is likely. Post-mortem examination of the brain can definitively determine whether the cat was affected by the condition.

There is no cure for cerebellar abiotrophy, and symptoms are not reversible. Treatment recommendations will depend on whether additional causes were found during the diagnosis. If a tumor is present, surgery may be recommended. If the condition is found to be congenital or hereditary, treatment will be purely supportive with a focus on improving the quality of life for the affected cat. In some cases, medications such as amantadine, acetyl-l-carnitine, co-enzyme Q10, and buspirone have helped with symptom management. Owners should always consult their veterinarian prior to administering medication as some medicines can cause the condition to worsen. In some cases, ongoing physical therapy such “towel walking,” hydrotherapy, or the use of a homemade wheelchair may be recommended.

Due to the lack of coordination and depth perception caused by the condition, affected animals tend to be prone to accidents and injury. Activity should be restricted to safe areas away from stairs, swimming pools, balconies and sharp corners. Ramps may be used to help the cat with getting on and off furniture and stairway railings should be blocked with plexiglass. Raised food dishes and modified litter boxes can also help cats to adapt. Cats with the condition should always be kept indoors as they will be highly vulnerable to predators and may have difficulty getting out of the way of cars or other dangers.

Most cats affected by cerebellar abiotrophy can learn to live fairly comfortable lives and usually have a normal lifespan. If the degeneration reaches a point where the cat is unable to walk or perform basic functions, owners must discuss the possibility of humane euthanasia with their veterinarian.