grey area: dr. kim smyth discusses cerebellar diseases
The cerebellum is a part of the brain. In fact, the word ‘cerebellum’ is Latin for ‘little brain.’ In dogs and cats (and all other mammals), the cerebellum sits under the larger cerebral hemispheres towards the back of the brain, where it acts as the control center for movement, balance, and coordination.
While the cerebellum isn’t responsible for initiating movement (another part of the brain does this), it does modify the movements once they begin. It also regulates posture, awareness of the body in space, and muscle tone. Without the cerebellum, your pets would have choppy, uncoordinated movements and tremors.
I thought we could spend today talking about cerebellar disease. While diseases of the cerebellum aren’t common, they do occur. Signs of trouble in the cerebellum include head and body tremors, an exaggerated gait with uncoordinated steps, bunny hopping with hind limbs and increased muscle tone or stiffness.
Here are some of the more common underlying causes of cerebellar diseases:
In this inherited condition, cerebellar nerve cells die prematurely after affected dogs or cats are born. The signs of cerebellar abiotrophy are progressive, but the age of onset of clinical signs as well as the speed of deterioration varies between patients. Cats and dogs of any breed can be affected, but Kerry Blue Terriers, Gordon Setters, and Collies are predisposed due to hereditary factors. There is currently no treatment. Affected animals should be indoor pets and would do best on carpeted or other non-slip surfaces.
Adult onset cerebellar degeneration
Similar to cerebellar abiotrophy in young animals, this progressive condition affects older dogs and cats of any breed. Clinical signs typically start in the hind limbs and eventually affect all four limbs and the head. Humane euthanasia should be considered if quality of life is poor.
Rottweilers, Sheepdogs, and Papillons are particularly prone to this inherited degenerative disease involving swelling and atrophy of the cerebellar nerve cells. There is currently no treatment. Affected pets should not be used for breeding.
Unlike the above degenerative conditions, in cerebellar hypoplasia the cerebellum simply fails to form properly. This is a congenital condition seen more often in Chow Chows, Boston Terriers, Airedale Terriers, Irish Setters, Wire Haired Fox Terriers, and Bull Terriers. Cats can also be affected—especially those exposed to feline panleukopenia virus in utero. Disease severity ranges from mild cerebellar changes to complete absence of this important hindbrain structure. Generally, signs are not progressive and they may even improve with age.
If you recall from the blog on vascular events (or strokes), when cells of any kind (including neural cells in the brain) are deprived of blood and oxygen, they die. The nerve cells of the cerebellum are no different.
Many infectious diseases can cause cerebellar damage, including:
Panleukopenia in cats
Feline Infectious Peritonitis (FIP)
Canine distemper virus
Rocky Mountain Spotted Fever
Remember, cerebellar disease is rare. Even in the breeds listed above as genetically predisposed to cerebellar conditions, it is unusual. If your pet shows clinical signs similar to those listed above, try not to jump to rash conclusions. Instead, schedule an appointment with your veterinarian to find out what could be going on.