Cerebellar Hypoplasia in Cats

Cerebellar hypoplasia: Two long (and baffling) words. Let’s break them up into something understandable.

First, the cerebellum: The cerebellum is the part of the brain which coordinates movement. Think of keeping your balance on the shifting deck of a ship at sea, and it’s your cerebellum (along with other internal mechanisms) taking up the slack to keep you upright.

The cerebellum also helps with fine motor skills (such as opening a tin of cat food) and coordination (spooning the food into the cat’s bowl.) These are all things we take for granted, indeed much like switching on the TV and expecting to see a picture, the cerebellum does its stuff without us giving conscious thought to how.

Now to tackle the other word: Hypoplasia. The ‘hypo’ part means ‘low’, as in hypothermia, which is what happens if you stand out in the cold without warm clothing. The ‘-plasia’ means to mould or form, so throw the two parts together and you get low. . . or under development.

By now you’ve raced ahead and put together that ‘cerebellar hypoplasia’ is an under-development of the brain’s balance centre, the cerebellum. Ta-dah! That’s exactly what it is. You may also have heard cerebellar hypoplasia cats referred to as ‘wobbly cats’ or the condition referred to as ‘wobbly cat syndrome’.

But what does this mean for a cat?

Symptoms of Cerebellar Hypoplasia

What do we know so far and what clues does this give us about the symptoms?

A cat with cerebellar hypoplasia has a brain that hasn’t fully developed its balance and coordination centres. Picture a cat with a drunken walk. These cats may have tremors or shakes; they stagger around and can have difficulty with muscular coordination. They often have what’s called an ‘intention tremor’, which means the harder they focus on doing something the worse the shake becomes.

They also find it difficult to do basic things like eating or going to the litter box. This is because they can see the food and know what they want to eat, but can’t coordinate their muscles to walk over and put their head in the bowl. Think of this like playing on a computer gaming console but with a broken controller: You want the animated character to pick up an energy pack but you’re unable to move him to the right spot.

Image: Emily Hall via Kitty Cat Chronicles

Can any Cat Develop Cerebellar Hypoplasia?

No! Its what’s called a developmental disorder. This means the growth of the brain was interrupted when the kitten was in the womb, and the brain failed to develop properly. So an adult cat that grew normally in the womb and was a healthy kitten is completely in the clear for cerebellar hypoplasia.

Also, an adult cat that was normal but develops a drunken walk doesn’t have cerebellar hypoplasia. The explanation for these symptoms is going to be different, such as heart disease, high blood pressure, toxoplasmosis, poisoning, encephalitis, or a brain tumour.

So yes, this does mean affected kittens are born with the condition. Actually, in a bizarre way, this is good news because this is also a non-progressive disease. This means that things are as bad as they are and won’t deteriorate with time (such as a progressive disease does.)

How Serious is Cerebellar Hypoplasia?

The big picture is that cerebellar hypoplasia is disabling to a kitten, but with a caring owner, they can usually cope. But these kittens don’t have the nimbleness and speed necessary to escape from danger, so it’s essential to raise them as indoor cats.

It’s also important to know that this isn’t an all-or-nothing condition. A kitten may be mildly or severely affected, depending on how much damage was done in the womb. So the signs may vary from a slightly wobbly kitten to one that has difficulty standing.

Whilst a slight wobble is something the kitten can cope with, an extreme case may be severely disabled. However, the good news (if that’s the right choice of words) is the condition isn’t going to deteriorate, so a kitten that’s doing fine right now is likely to keep on that way.

Image: Emily Hall via Kitty Cat Chronicles

Why do Cats get Cerebellar Hypoplasia?

We’ve already mentioned damage to the developing foetus, but how does this damage happen?

The most common cause is the mother cat becomes infected with the feline panleukopaenia virus in the later stages of pregnancy. This virus crosses the placenta to the kittens in the womb and attacks rapidly dividing cells. Unfortunately, late pregnancy is also when the kitten’s brain is growing most rapidly and so the virus hits the equivalent of a jackpot.

However, this isn’t the only cause. Severe malnutrition in the mother will damage her kittens’ development, as will head trauma to new-born kittens.

How is Cerebellar Hypoplasia Diagnosed?

Many vets diagnose this condition based on the clinical signs in a very young kitten. However, when a vet is presented with a stray adult cat that has poor coordination, other health problems causing similar symptoms need to be ruled out. One of these is toxoplasmosis, where the parasite attacks the brain and interferes with motor function.

Ultimately, a definitive diagnosis is made by taking a picture of the brain with an MRI scanner. This enables the technician to see how small the cerebellum is, making the diagnosis a ‘no-brainer.’

Image: Emily Hall via Kitty Cat Chronicles

Helping a Kitten with Cerebellar Hypoplasia

Firstly, prevention is better than cure. If you’re planning on breeding, make sure the mother’s vaccinations are up to date (panleukopaenia is a core constituent of vaccine protocols) before she’s mated. And of course, make sure she’s fed a well-balanced diet.

However, if you already have a kitten with cerebellar hypoplasia, then a few adaptations to your home can make a big difference. Things like making a shallow ramp for the kitty to climb into her litter tray will help. Also, try raising the food bowls slightly off the ground so the kitten doesn’t have to dip her head down quite as much.

So there we have it: Cerebellar hypoplasia: An avoidable condition affecting kittens, but one most kittens are able to live with so long as they stay indoors.

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PS. Editors note: Whilst many CH ‘wobbly’ cats may be best suited to an indoor lifestyle, there is always an exception. Meet Sophie a very special wobbly kitty. . .  as you can see from the video below, nothing stops her from leading a full and active life.

Photos used in this article are published with permission from Emily Hall, you can read more about Sophie and cerebellar hypoplasia on the Kitty Cat Chronicles blog.