Cerebellar Hypoplasia in Cats

Cerebellar hypoplasia is a neurological disorder. It is condition whereby the cerebellum, a part of the brain which is essential for the working of a body's central nervous system, is underdeveloped. The central nervous system of vertebrates is responsible for many functions of the body, including movement. It is essential for coordination, harmonizing muscle contractions and altering the intensity of movement.

The decrease in size of a cat's cerebellum due to cerebellar hypoplasia leads to disorganization of the cerebellar cortex and a deficiency of granular and Purkinje neurons. The cerebellum can no longer accurately control the cat's movement, leading to their inability to regulate the correct motion of steps, the strength used for a certain movement and inhibits coordination. This is a process known as dysmetria.

Since cerebellar hypoplasia is a developmental condition which mainly affects kittens in utero. It can be passed on Cats cannot develop cerebellar hypoplasia later in life. However, since the extent of the condition varies, not all kittens will behave the same way.

Kittens will take time to develop. It takes time for them to even open their eyes. In their early stages, some kittens may not show signs of cerebellar hypoplasia. Others will manifest acute signs from their first week of life. This symptoms will become more pronounced as they develop further.

Cerebellar damage can be due to either congenital or acquired reasons. However, the damage to the cerebellum usually takes place when the cat is either a fetus or in the neonatal stage. This prohibits the brain to develop properly as they age.

• Congenital causes: although hereditary causes of cerebellar hypoplasia have been found in other animals, there is yet to be conclusive evidence this is the case for cats. The most common congenital cause is due to the feline panleukopenia virus (FPLV). If a pregnant mother has the virus, it can be passed down in utero and the kittens will develop symptoms. It can also be passed on during breastfeeding. For this reason, we should never immunize a pregnant cat for FLPV. Cerebellar abiotrophy where the Purkinje neurons is a rare cause of this problem, as are leukodystrophies and lipodystrophy. Idiopathic cerebellar hypoplasia is also a cause, especially since not all cats will have a proper diagnosis.
  
  
• Acquired causes: inflammation caused by diseases such as granulomatous encephalitis (toxoplasmosis and cryptococcosis), feline infectious peritonitis, parasites such as Cuterebra and feline rabies can cause cereballar hypoplasia in infant kittens. They can also be due to diffuse degenerations caused by toxins from plants or fungi, organophosphates or heavy metals.

The most common cause of cerebellar hypoplasia in kittens is contact with the feline panleukopenia virus (feline parvovirus), either by infection of the mother cat during gestation or when a pregnant cat is vaccinated with a modified live vaccine of feline panleukopenia virus.

In both forms the virus reaches kittens intrauterine and causes damage to their cerebellum. The damage caused by the virus mainly affects the outer germinal layer of the cerebellum. By destroying these developmental cells, the growth and development of the cerebellum is extensively diminished.

The clinical signs of a cerebellar hypoplasia become evident when the kitten begins to walk. The wobbly gait which typifies the condition had led to it being referred to colloquially as wobbly cat syndrome. However, we need to distinguish from other issues which affect a cat's gait such as degenerative neurological diseases or other causes of feline ataxia.

The main signs of feline cerebellar hypoplasia include:

• Hypermetry (walking with legs apart with wide jerky movements)
• Ataxia (lack of coordination)
• Tremors (especially of the head, which worsen when eating)
• Jumping erratically with little precision
• Shaking before they try to move
• Abdomen rocks while walking
• Sudden, jerky and awkward limb movements
• Fine oscillatory or pendulous eye movement
• Extends all four legs when at rest
• Deficiency may appear in the bilateral threat response

Since the extent of the disease depends on the extent of the cerebellar damage, symptoms range from mild to very serious. When it is acute, the kitten will have difficulty eating and walking which can be life threatening. If the kitten can't walk, we may see the mother cat move them more than the other kittens in a litter.

A definitive diagnosis of feline cerebellar hypoplasia is made by laboratory or imaging tests. Generally the manifestation of symptoms can point to a cerebellar disorder in a week-old kitten, often being sufficient to make the diagnosis of this disease.

Clinical diagnosis

When a kitten has uncoordinated gait, exaggerated gait, or a wide stance with extended or trembling legs, feline cerebellar hypoplasia due to panleukopenia is suspected. This is especially the case when these movements are exaggerated when they approach their food bowl and if they cease when at rest.

Laboratory diagnostics

Laboratory diagnosis will always confirm the disease by a histopathology examination after taking a sample of the cerebellum and detecting hypoplasia.

Diagnostic imaging

Imaging tests are the best diagnostic method for cerebellar hypoplasia in cats, specifically the use of magnetic resonance imaging or computed tomography. They will show the cerebellar changes indicative of this process. However, many veterinarians will not issue these tests as they are often costly and treatment of cerebellar hypopaslia in cats can be issued without it.

Hypoplasia of the cerebellum in cats has no cure nor treatment. It is not a progressive disease. Once the kitten has completed their development, we will know the extent of their symptoms. Although cats with cerebellar hypoplasia will never move like an able-bodied cat, they can have a high quality of life. They will need some specific care and considerations, but we should not euthanize them or refuse adoption because of this issue. In fact, their reduced mobility might be a benefit for some guardians.

For those with the ability, cats with cerebellar hypoplasia can be provided with neurological rehabilitation using proprioception and balance exercises or active kinesitherapy. This way the cat can learn to navigate their environment and compensate for their limitations. This will often involve avoided the high places cats usually love or making movements which require certain levels of coordination.

The life expectancy of a cat with cerebellar hypoplasia can be the same as a cat which is not affected by it. Stray cats have a greater likelihood of developing the disease since they are more prone to infection. We need to ensure the cat is treated for any FPLV issues and we need to do what we can to avoid transmission of any viruses. Stray cats are also more at risk for nutritional deficiencies and other problems which may affect the cerebellum.

Vaccination of cats is very important. If we vaccinate female cats for panleukopenia, this disease can be avoided in their offspring as well as the systemic problems caused by panleukopenia in cats (also known as distemper).

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

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