Question: We have a family cat named Bob who is 11 years old. Bob was considerably overweight in the past. In the past three months Bob has dropped all his excess weight and now is nearly skin and bones, no fat at all even in the tummy area. So obviously we think something is wrong. However, he has more energy, can now jump up onto counter tops, desks etc., where he could not when he was overweight. He eats, drinks water, and relieves himself as normal. We have not changed his diet. He will sleep more during the day and is more awake at night. There seems to be nothing wrong or hurting him. The anus is clean, no rice-like matter that could be worm eggs. His fur is shiny. We prefer not to see a vet unless all else fails, so what can we do ourselves? The obvious question is why would he be losing all his weight and how long could he live this way?
Answer: Despite your reluctance to see a veterinarian, there is nothing that you can do on your own. You must book an appointment if you want to keep your cat alive. Rapid weight loss despite a good appetite is not normal, and if your cat has been reduced to skin and bones, you would do well to get him to a veterinarian as soon as possible.
Since your cat eats well yet continues to lose weight, there are a number of possible diseases to consider. On top of the list is hyperthyroidism, a disease that is due to an overproduction of thyroid hormone by the thyroid gland. Pets with hyperthyroidism tend to have a very high metabolic rate, which “burns up” calories very quickly, causing the patient to lose weight despite eating well. Treatment for hyperthyroidism is usually very effective and may simply involve changing your cat’s diet to one that is iodine-restricted (Hill’s Y/D). Oral medication (e.g. methimazole) or, in some cases, radiation therapy are also possible treatments if the diet change proves ineffective or is not possible.
If your cat does not have hyperthyroidism, there are still some other possibilities to consider. For example, your cat could have diabetes mellitus. Diabetic cats lack insulin and this makes their blood sugar unavailable to their bodies. As a result, the pet becomes hungrier and loses weight as the diabetes progresses.
In some patients, the intestines may not be absorbing nutrients properly, which results in pets eating a lot but not absorbing much of what they eat. Called “malabsorption syndrome”, this disease causes patients to lose weight despite a healthy appetite. Similarly, any chronic intestinal disease can also result in weight loss.
Intestinal parasites should not be ruled out just because you do not see any evidence of worms or worm eggs in the stools. This is because a microscopic fecal test is necessary to accurately rule out intestinal parasites.
Chronic and low-grade infections can also lead to significant weight loss. In cats, feline leukemia virus and feline infectious peritonitis virus are frequently implicated. Unexplained weight loss can also be due to cancer.
Please call your veterinarian as soon as possible to set up an appointment. Your cat’s life depends on it.
Dr. Bernhard Pukay is an Ottawa veterinarian. Address letters to Pet Care, Ottawa Citizen, P.O. Box 5020, Ottawa K2C 3M4. Due to the volume of mail, not all letters can be answered.