Signs of a brain lesion may be dramatic, like a full-blown grand mal seizure, or subtle, like a change in movement or behavior. Other signs might make you suspect that your cat has a brain tumor, but these may be due to something as simple as an ear infection. If you notice something is wrong, though, prompt veterinary consultation can make a huge difference.
“Most commonly, owners will notice a change in behavior, what we refer to as ‘dull mentation.’ Additionally, many cats will show other clinical signs such as circling, or abnormal gait or seizures, depending on the location of the lesion,” says Yael Merbl, DVM, DECVN, assistant professor of neurology in the department of clinical sciences at Cornell University’s College of Veterinary Medicine.
Neurologic signs may come on abruptly or gradually, with your cat starting to show changes in gait over time, having trouble jumping up on the couch, or showing some signs of vision loss, such as walking into furniture.
Sometimes it is just dullness, as Dr. Merbl says, with affected cats no longer wanting to play, not reacting as they normally would to a tossed treat, or failing to come when you call. Of course, every cat can have an off day, but if this happens more than once in succession, assume something is wrong and have your cat checked by a veterinarian.
Older Cats
Cancerous brain tumors can be a concern, especially for middle aged to senior cats. While clinical signs often develop gradually, some cats show acute problems when the cancer grows beyond a threshold size. Luckily for cats, the most common type of brain cancer is a meningioma, which is often amenable to surgery if caught early. Another brain cancer commonly seen in cats called a glioma has a much worse prognosis.
Ischemic infarcts, or strokes, cause cell death in the portion of the brain that is deprived of oxygen. These can be due to bleeding secondary to hypertension (primary or secondary due to kidney disease or thyroid disease) or from a blood clot, which could result from a clotting disorder or other metabolic problems.
Severe liver disease can cause hepatic encephalopathy due to the buildup of toxins in the blood. These toxins can cross the blood brain barrier and lead to neurologic signs.
In a young kitten, this could be due to a congenital condition called a portosystemic shunt (PSS), in which an abnormal blood vessel allows blood draining from the GI tract to bypass the liver and its detoxifying action, resulting in the delivery of toxins to the various organ systems. PSS may be amenable to surgical intervention.
Older cats with liver failure often require medical treatment with supplements, sometimes antibiotics, and often dietary changes.
There is no definitive treatment for strokes in cats. Supportive care, sometimes including the placement of a feeding tube, is important. Luckily, many cats will improve over time. Rehabilitation treatments can help with both speed and degree of recovery.
Masquerading Diseases
Some problems, like infections of the middle ear, may cause signs similar to a brain problem, such as a head tilt, nausea, and circling. You might notice an odor or a discharge from your cat’s ear.
These infections can be painful, and your veterinarian may need to sedate your cat to fully examine her ear(s) and to thoroughly clean and flush the ear canal. Ear drops, and sometimes oral antibiotics, will be prescribed. Ear mites may be the primary problem, and they are also treated medically.
FIP, or feline infectious peritonitis, is another cause of brain problems in cats. FIP is a devastating infectious disease in young cats that can be fatal. The development of new drugs, including a compound called GS-441524, has recently provided hope for cats diagnosed with FIP. Unfortunately, these drugs are not yet FDA approved.
FIP can cause central nervous system disease involving the brain or the spinal cord (often referred to as the dry form of the disease), but it can also cause a “wet” form, in which fluid accumulates in body cavities.
Bottom Line
If your cat shows any neurologic signs, she should have a veterinary visit scheduled promptly. A referral to a veterinary neurologist and further diagnostics may be recommended.
Yael Merbl, DVM, DECVN, assistant professor of neurology in the department of clinical sciences at Cornell University’s College of Veterinary Medicine.
