By Dr. Jennifer Coates
When veterinarians are faced with a sick cat, the first thing they do is put together a list of the various diseases that might be responsible. The common ones are at the top and the rare ones are at the bottom. This is called a differential diagnosis. Veterinarians then make a diagnostic plan to start confirming or eliminating each potential disease. Usually the answer is found at the top of the list, but sometimes doctors get all the way to the rare diseases at the bottom before a diagnosis is reached. Here are some cat diseases that, while rare, still deserve to be included in a cat’s differential diagnosis.
Lots of diseases can make cats itchy, including common ones like flea infestations and seasonal allergies. Notoedric mange (also called feline scabies) is another possibility. Notoedric mange is caused by microscopic mites that are passed between cats. The mites burrow into the skin where they cause thick crusts and intense itching, often around the head, neck, and front legs. Treating all cats that live together with a medication to kill the mites should take care of the problem.
Feline hyperesthesia is a diagnosis of exclusion. Cats with feline hyperesthesia can develop a number of unusual behaviors, including biting themselves to the point of self-harm, rippling skin, odd vocalizations, random periods of running and/or jumping, and even seizure-like episodes. Before a cat can be diagnosed with hyperesthesia, the more common causes of symptoms like these have to be ruled out. Treatment with an anti-anxiety medication helps some cats with feline hyperesthesia.
Many cat owners have heard of feline infectious peritonitis (FIP) even though the condition is quite rare. FIP is caused by a viral infection. The odd thing about FIP is that most cats are infected with the causative virus (feline coronavirus) when they are young, but only a small proportion of infected cats go on to develop FIP at a later date due to the virus mutating within their bodies.
Cats with FIP can develop a range of symptoms, including poor appetite, lethargy, weight loss, fluid build-up in the abdomen or chest, enlarged lymph nodes, difficulty breathing, eye abnormalities, difficulty walking, behavioral changes, and seizures. Treatment for FIP is limited to supportive therapy.
Acromegaly is caused by an overproduction of growth hormone within the body, often due to a tumor within the pituitary gland. The result is an excessively large cat with a big head and enlarged organs. Acromegaly is also associated with the development of diabetes mellitus and heart disease. Treatment for acromegaly in cats has been unrewarding.
Dysautonomia (also called Key-Gaskell syndrome) is caused by abnormalities within the nervous system. The cause has not been identified. Cats with dysautonomia typically experience poor appetite, vomiting, pupils that don’t respond to light normally, elevation of the third eyelid, dehydration, constipation, difficulty eating and urinating, poor tear production, and a slow heart rate. Treating the symptoms of dysautonomia can make these cats feel better, but most are eventually euthanized due to poor quality of life.