Wobbly cat syndrome

What is Cerebellar hypoplasia?

Cerebellar hypoplasia is a developmental brain condition affecting kittens from birth — some people call them ‘wobbly cats.’ Cerebellar refers to the cerebellum, an important part of the brain, and hypoplasia means it isn’t fully developed. Many cats with cerebellar hypoplasia live a relatively normal life, whereas others have more severe difficulties requiring a high level of support.

A cat’s brain anatomy

To fully understand this condition, let’s first take a look at the brain. Cats’ brains are complex structures containing around 300 million tiny neurons (nerve cells). Dogs have just over half this amount (as an impartial vet, I couldn’t possibly comment about which species is the most intelligent!). Your cat’s brain has a storage capacity over 1,000 times bigger than the average iPad with a far superior processing speed (around 6.1 trillion operations per second compared to an iPad’s mere 170 million per second).This impressive piece of kit fits neatly inside your cat’s skull measuring about 5cm in length and weighing only 30 grams!

Here's a quick guide to which bit of the brain does what:

• The olfactory lobe is made of two ‘bulbs’ and sits at the bottom front part of the brain. It receives signals from your cat’s nose and mouth and processes everything smell related.
• The frontal lobe in cats is a much smaller portion of the brain than in humans. We have a more developed emotional regulation system than cats, allowing us to navigate complex social interactions. In both species, the frontal lobe is important for memory, voluntary movements, and behaviour.
• The temporal lobe has a few roles including hearing and memory (recognising objects).
• Below the temporal lobe are the thalamus, hypothalamus, and pituitary gland.These areas control homeostasis — the body’s internal workings such as temperature, hormone regulation, and sleep.
• The cerebellum is a relatively small part of the brain. Don’t be fooled by its size though, it’s packed full of some hugely important neurons. The cerebellum’s functions include controlling movement, balance, eye movements, and coordination.

What causes Cerebellar hypoplasia?

Cerebellar hypoplasia can affect an entire litter or only one or two kittens. ‘Normal’ siblings aren’t at risk because cerebellar hypoplasia itself isn’t contagious (the brain damage occurs before birth).

Kittens are born with cerebellar hypoplasia if their mother contracts feline panleukopaenia virus (FPV) while pregnant. The virus spreads to unborn kittens, interfering with their normal brain development. If FPV infects very young kittens (less than four weeks of age), they may show signs of cerebellar hypoplasia as the virus can damage their young, still-developing brains.

FPV is a highly contagious infection causing vomiting and diarrhoea. It spreads via the oro-faecal route (cats ingest faecal particles containing the virus) and from contact with contaminated objects (food bowls, bedding, clothes, and even hands!). Cats may need supportive treatment (such as intravenous fluids) while they recover. Sadly, some cats become too unwell and die after catching FPV.

Other causes of cerebellar hypoplasia include physical trauma, other brain infections (such as toxoplasmosis), or kittens born from mothers who were severely malnourished during pregnancy.

What are the signs of Cerebellar hypoplasia?

Cerebellar hypoplasia is neither painful nor contagious. Some cats have very mild symptoms and can lead a relatively normal life. Others have more severe difficulties that require a high level of care. But with the right support, even severely affected cats can have a good quality of life.

Since one of the main functions of the cerebellum is movement, many kittens don’t show signs until they start to stand and walk.

Those mildly affected may have only one or two of the following symptoms, whereas severely affected cats will show more:

• Wide-legged stance — this helps kittens to balance and stay upright.
• Swaying from side to side when they walk.
• Hypermetric gait (cats take exaggerated, big steps often described as ‘goose stepping’).
• Head tremors or a nodding movement — this may worsen when the kitten is concentrating, such as when they try to eat.
• Intention tremors affecting the whole body may occur when the cat tries to do a specific activity (playing with a toy or digging in their litter tray).
• Climb using their nails instead of jumping up.
• Balance issues — kittens are quite clumsy anyway but those with cerebellar hypoplasia may fall over more often than normal.

Seizures or tremors?

Cerebellar hypoplasia doesn’t cause cats to have seizures (fits) but a head tremor can look quite similar. Some cats with cerebellar hypoplasia have additional brain abnormalities that may cause seizures. It’s always a good idea to video your cat having any episodes as your vet can tell the difference between a head tremor and a seizure. Medications are available to control seizures in cats.

Diagnosing Cerebellar hypoplasia

There isn’t a specific test for cerebellar hypoplasia. Your vet will carry out a full neurological assessment (a check of the nervous system) of your kitten. As part of this examination, your vet tests your kitten’s reflexes, records any movement difficulties, and checks their eyes. They’ll also do a full health check including listening to your kitten’s heart, recording their weight, and making sure they don’t have any parasites (fleas and worms).

Your vet can most likely diagnose your kitten’s cerebellar hypoplasia based on their clinical findings. If they need more information (or to confirm a diagnosis), they may refer your kitten to a neurologist (vet specialising in the brain and nervous system). An MRI scan may be helpful to measure the size of your kitten’s cerebellum and give a definite diagnosis of hypoplasia.

What’s the outlook for kittens with Cerebellar hypoplasia?

While there’s no treatment for cats with cerebellar hypoplasia, there’s plenty you can do to help them stay healthy. Unless they have other health conditions too, kittens with cerebellar hypoplasia can have their vaccinations and neutering operation as normal.

Many cats and kittens only need minor lifestyle adjustments in order for them to enjoy a full life. More severely affected kittens may need a much higher level of support.

Possible adjustments for cats and kittens with Cerebellar Hypoplasia include:

• Raising feed bowls for easier access to food and water.
• Use heavy, tip-proof bowls placed on wipe-clean matting — cats with cerebellar hypoplasia can be messy eaters!
• A litter tray with deep sides is helpful — cats learn to lean on the sides for support while they use the facilities.
• Provide steps to help them safely reach their favourite high spots (windowsills and beds etc.)
• If your kitten struggles with jumping down from surfaces, a cushion crash mat can break their fall and protect against injury.
• Some cats need a bit of help with their toilet hygiene (washing paws and sometimes bums!)
• Your vet can advise you on the best diet for your cat but usually a palatable, easy to eat food works well.

Can cats with Cerebellar hypoplasia safely go outside?

This all depends on the cat’s individual symptoms. Most cats with cerebellar hypoplasia should stay indoors but some can manage supervised play in an enclosed, safe garden, or adapted run.

Is Cerebellar hypoplasia preventable?

Yes, it is! Core cat vaccines protect against feline panleukopaenia virus (alongside feline rhinotracheitis, feline calicivirus, and feline leukaemia virus). Kittens can begin their course of two injections at nine weeks of age then have yearly boosters to keep their immunity topped up. Kittens born from vaccinated females are automatically protected against FPV and therefore highly unlikely to develop cerebellar hypoplasia.

Life with a cat affected by cerebellar hypoplasia Living with a ‘wobbly’ cat can be hard work but ultimately very rewarding and joyful. There are various online support groups where owners can share their experiences and helpful tips for life with these very special kittens. Your veterinary team are also a valuable source of support and information — it’s surprising how many cats with cerebellar hypoplasia end up living with veterinary staff!