Weight Loss and Poor Appetite in Elderly Cats

Weight loss and/or poor appetite is a common problem in elderly cats. A cat who used to be a good eater suddenly becomes selective, refusing to eat any food consistently. Concerned owners try all kinds of foods including a variety of canned and dry food, human baby food and home cooking. Unfortunately, the results are disappointing, the cat will eat it for a few days then refuse. It is one of the most frustrating syndromes veterinarians and owners face.

Here are some of the common causes of weight loss and decreased appetite in older cats and how they are diagnosed:
1)  Kidney disease – When uremic toxins build up in the bloodstream from poorly functioning kidneys, the condition often leads to gastric ulcers, anorexia and vomiting. Kidney disease can be diagnosed with blood work, a urinalysis and sometimes x-rays or an ultrasound.
2) Diabetes mellitus – In my experience, the most common cause of weight loss in obese cats is diabetes. The blood sugar in cats with diabetes skyrockets leading to weight loss, excessive thirst, frequent urination and lethargy. Diagnosis is based on finding a high blood sugar level in combination with glucose in the urine.
3) Pancreatitis – Inflammation of the pancreas or pancreatitis causes abdominal pain, anorexia and weight loss in middle to older aged cats. Diagnosis requires a special blood test called an fPLI.
4) Liver Disease – Many older cats suffer from either primary liver disease such as cholangiohepatitis or secondary liver disease like hepatic lipidosis. A presumptive diagnosis is made with blood work and ultrasound. A biopsy is required for the final diagnosis.   
5) Inflammatory bowel disease – Inflammation of the lining of the intestine causes anorexia, vomiting, diarrhea and weight loss in cats. Diagnosis requires a biopsy of the intestines.
6) Combination of the above conditions – Some of these conditions often occur together such as diabetes is often found with pancreatitis and inflammatory bowel disease.   
Although the conditions listed above are the most common, I have seen a few cats that are never diagnosed. In these frustrating cats, the lab results and ultrasound are all within the normal range. To help these cats out, I have had good luck putting them on an anti-nausea medication.
Please Note: Even though cats with hyperthyroidism will lose weight, I did not include that condition on this list because most of these cats have voracious appetites.

Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.