Cerebellar Hypoplasia in Cats (Wobbly Cat Syndrome)

Cerebellar hypoplasia has existed in cats for a long time, but it’s only since the 1960s that we’ve learned more about the cause of this developmental disorder. Now, you can find videos of wobbly cats living their best lives all over social media! 

Continue reading to find out what cerebellar hypoplasia in cats is and how to manage your wobbly cat at home.

What Is Cerebellar Hypoplasia?

Cerebellar hypoplasia in cats, also known as wobbly cat syndrome or CH, is a developmental condition in which a specific part of the brain, called the cerebellum, fails to develop properly. 

The cerebellum, which means “little brain” in Latin, is a part of the central nervous system within the back of the skull between the cerebrum and brainstem. Specifically, the cerebellum is responsible for coordination and balance. The word “hypoplasia” refers to underdevelopment of a particular organ or tissue, meaning the affected organ or tissue is often smaller than normal.

Although cerebellar hypoplasia is lifelong and untreatable, there’s good news for cats with CH! Wobbly cat syndrome isn’t painful, and cats with cerebellar hypoplasia typically have a great quality of life. Importantly, wobbly cat syndrome isn’t contagious between cats. CH is different from a lot of other neurological disorders in that it’s typically present at birth, doesn’t worsen over time, and has signs restricted only to the cerebellum.

Although we don’t know the true prevalence of cerebellar hypoplasia in cats and the condition is uncommon overall, CH is among the leading causes of neurological signs in kittens or young cats. It’s the most common condition affecting the cerebellum of kittens.

Causes of Cerebellar Hypoplasia in Cats

The development of cerebellar hypoplasia in a cat is truly dependent on the health of their mother. A kitten can develop wobbly cat syndrome if their mother receives a modified live virus vaccine (typically their annual FVRCP vaccine) or contracts the panleukopenia virus during pregnancy. Panleukopenia virus is a parvovirus (same family as canine parvovirus), and it usually causes diarrhea and immune system suppression in adult cats. The reason for these signs in adults is that the panleukopenia virus preferentially attacks rapidly dividing cells. In an adult cat, the cells that line their intestines and their white blood cells are some of the most rapidly dividing cells, so they are affected by the virus most severely.

So how does this lead to cerebellar hypoplasia in a kitten? During fetal development and within the first two weeks of life, the cerebellum is undergoing rapid development. If the kitten becomes infected with parvovirus either through natural infection or a live vaccination while in the uterus or within the first two weeks after birth, the virus can affect the rapidly dividing cells of their cerebellum. This will cause them to have an underdeveloped cerebellum.

Interestingly, CH may affect only one kitten in a litter, or it may affect all of them. Kittens affected by panleukopenia virus after two weeks of age are likely to have severe signs of the virus itself but are highly unlikely to develop wobbly cat syndrome.

Infection with panleukopenia virus is the most common cause of CH by far, but the condition could also theoretically develop if the pregnant mother cat is really malnourished or if the kitten suffers a head trauma that affects the cerebellum during its rapid stage of development.

Symptoms of Wobbly Cat Syndrome

Even though cerebellar hypoplasia is usually present at birth, it’s often not apparent until the kitten is trying to stand and walk on their own. This is usually around 2-3 weeks of age. Clinical signs do not worsen over time but may slightly improve as the cat adjusts to their disability.

Signs of wobbly cat syndrome include:

• Jerky, shaky, uncoordinated walking
• Appearing to sway from side to side when walking
• A high-stepping gait called hypermetria (sometimes called goose-stepping)
• Wide-based stance
• Mild head tremors at rest
• More noticeable tremors when the kitten makes an intentional movement, such as trying to play with a toy or bending over to eat or drink from a bowl (intention tremors)
• Clumsy placement of feet
• Leaning against walls for support

The uncoordinated, high-stepping walk of this condition is often referred to as “cerebellar ataxia.”

Clinical signs vary in severity depending on how developed the cerebellum was when the kitten was infected. Most cats with cerebellar hypoplasia will have an uncoordinated gait and intention tremors, but they will be able to eat on their own and use the litter box. In severe cases, the cat may struggle to get into and out of the litter box and could be at significant risk of falling and injuring themselves.

Remember that this is a developmental disorder. If your adult cat develops these clinical signs after previously having normal balance and coordination, it is extremely unlikely to be cerebellar hypoplasia. In this case, we recommend having your pet promptly evaluated by a veterinarian.

Diagnosing CH in Cats

In most cases, the veterinarian can diagnose cerebellar hypoplasia based on history and physical examination. If you have a kitten who begins to show these signs around the time they begin walking, it is extremely likely to be CH, especially if you know the mother was infected with panleukopenia virus or received a modified live vaccine while pregnant. 

The disease should not worsen in severity over time and signs should be restricted to those that can be explained by underdevelopment of the cerebellum. If your cat has other clinical signs, such as a head tilt, blindness, seizures, or inappropriate mentation, additional diagnostics would be recommended to rule out other neurological diseases.

For a more definitive diagnosis, magnetic resonance imaging (MRI) can sometimes show a smaller than normal cerebellum. Typically, this is not necessary for diagnosis. Your veterinarian may also recommend other tests, such as blood work, to rule out other conditions. This is particularly more likely if they’re looking at an adult cat with an unknown history, such as one you have adopted from a shelter or a community cat you’ve welcomed into your home.

Treatment of Cerebellar Hypoplasia in Cats

Cerebellar hypoplasia is a developmental condition, which means we cannot treat it once it has developed. Instead, we focus on modifying the environment to keep our wobbly cats safe.

Your CH kitty must remain inside. If allowed to go outside, they’re at an increased risk of getting hit by a car or attacked by another animal due to their lack of coordination.

Lowering their head to the floor to eat or drink can worsen intention tremors. Because of this, it’s common for pet parents of CH cats to use elevated food and water dishes to reduce the trembling and make it easier for the cat to eat and drink.

Because the cat has a lack of coordination and a wide stance, it can be hard for cats to get into covered litter boxes, elevated litter boxes, litter boxes with high sides, and narrow litter boxes. In this case, we highly recommend a wide, uncovered litter box with low sides.

Cats with cerebellar hypoplasia should NEVER be declawed. Declawing can alter the way your cat walks, cause pain, and make it difficult for them to grip surfaces. Your cat with cerebellar hypoplasia will likely rely more heavily on their claws and may use them to grip if they’re losing their balance.

Keep in mind that your cat may be a fall risk. If your cat has mild CH, they may still be able to navigate cat trees and window seats, but if your cat’s cerebellar hypoplasia is moderate to severe, we recommend avoiding giving them access to heights. They will be more prone to injuries associated with falling.

Most cases of CH have a great prognosis if you adjust your home to keep them safe. Cats with cerebellar hypoplasia can still safely undergo anesthetic procedures, such as spay and neuter. More severe CH cases may require more assistance with getting into and out of litter boxes and eating and drinking. In severe cases, it may be best to restrict the cat to a safe room rather than giving them free range of the house, particularly if your home has a lot of stairs or areas the cat could fall from. Most cats with cerebellar hypoplasia will adapt to their disability and continue to be happy, healthy companions.

How to Prevent Cerebellar Hypoplasia in Cats

To prevent cerebellar hypoplasia in a cat, we need to prevent infection of their mother with panleukopenia virus. As previously mentioned, cerebellar hypoplasia can occur in kittens whose mothers become infected with panleukopenia virus or who are vaccinated with a live vaccine during pregnancy or within the first two weeks postpartum.

The best way to prevent CH is to get female cats vaccinated against panleukopenia prior to pregnancy. If your cat is already pregnant but due for her vaccines, your veterinarian may recommend holding off on vaccination until after the kittens’ first two weeks of life. Importantly, some places with a higher risk of infectious disease, such as an animal shelter or cattery, may still vaccinate pregnant cats. In these scenarios, the animal professionals have determined that the risk of infectious disease, which can be deadly, is greater than the risk of cerebellar hypoplasia.

If your cat is pregnant and has an unknown vaccination history, we recommend keeping them separate from other unvaccinated cats to prevent them from contracting panleukopenia virus. It’s extremely important that newborn kittens remain in a sanitary environment. You should avoid letting newborn kittens interact with other cats besides their mother to reduce the risk of disease transmission.