Also known as Spastic Cat Syndrome and Wobbly Cat Syndrome

The cat with cerebellar hypoplasia is abnormal from infancy, though it may not be clear that something is wrong until the kittens reach an age when they are expected to have some muscular coordination.

The cat with this disease clearly has balance issues: he walks with his legs widely placed for fear of falling and places his feet clumsily. He often leans against walls for support. Sitting still, he may look like a fairly normal cat, but once focused on a toy, food bowl, or friendly hand, tremors begin and get more severe as concentration becomes more intense. Still, despite the obvious impairment, cats with this condition are happy, able to feed themselves and use a litter box, and are felt to have a good quality of life.

Your Cerebellum and You

Graphic used with Permission: Centre for Neuro Skills, neuroskills.com

The cerebellum is a part of the brain nestled inside the base of the skull, as shown in Image 1. The cerebellum is involved in the involuntary aspects of moving our bodies, whether walking around, reaching for something, or just turning our heads. These all seem like voluntary activities, so it might be difficult to consider that there is something involuntary going on as well.

Consider walking across an uneven, perhaps rocky, terrain while carrying on a conversation with another person. Certainly, the decision to move from point A to point B is voluntary but the chances are you can walk across pretty uneven terrain without falling down or even thinking about where to put your feet. You can thank your cerebellum for that.

Your cerebellum receives information from your feet as well as from the vestibular apparatus in your middle ear. This information tells you where up and down are and where your body is in relation to up and down. Your cerebellum integrates all this information so that you can not only walk or run across uneven terrain without devoting any conscious thought to how to do so; you can turn your head, maybe even drink from a bottle of water, and look at another person while you are walking without (much) chance of falling down.

Your Cat’s Cerebellum and the Feline Distemper Virus

The cerebellum is obviously a complex piece of equipment. During fetal development, the cerebellum matures up until the last few days before birth and finishes its development in the first couple of weeks after birth.  Having a long period of development leaves the cerebellum especially vulnerable to an assortment of toxins for a long period of time. In the case of cerebellar hypoplasia, the culprit is the feline distemper virus (also called the panleukopenia virus). Following infection in the pregnant mother, growing nerves in the unborn kitten’s cerebellum are destroyed, ultimately yielding a tiny, improperly developed cerebellum and a disability for the kitten. The mother cat may not be actually infected during pregnancy to create this syndrome; if, while pregnant, she has been vaccinated with a modified live distemper vaccine, the most basic of all cat vaccines, it can have the same detrimental effects.

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Diagnosis

While imaging such as CT scanning or MRI can be used to confirm the underdeveloped tiny cerebellum, the diagnosis of this condition is usually obvious because of the following features:

• The condition is non-progressive (it doesn’t get worse).
• The cat is not weak; he's just uncoordinated.
• Intention tremors are evident when the cat is focused, but the cat looks largely normal if still.
• Walking is uncoordinated with a wide stance, often using the wall for support.

Treatment

No treatment can resolve the damage in a kitten with cerebellar hypoplasia. Some kittens are more severely affected than others. Owning a cat with cerebellar hypoplasia emphasizes managing the condition. The cat should be indoors only, and non-spill food dishes should be obtained. Most cats have a good quality of life and make up in personality what they lack in motor skills.

Prevention

This syndrome is easily prevented by vaccinating female cats for feline distemper when they are neither pregnant nor nursing kittens under the age of two weeks. This means that regular vaccination will prevent cerebellar hypoplasia in kittens. If a cat is pregnant, vaccination should be withheld during pregnancy and for a good three to four weeks after the kittens are born. 

If you think you have a CH cat, be sure your veterinarian concurs as there are other cerebellar diseases that are not as benign as this one. If you do have a CH cat, keep your home "cat-proofed" for his/her safety given issues with coordination and consider joining an on-line community for tips and camaraderie.