Weight Loss and Chronic Disease in Cats

Cachexia in Cats

If your cat loses an excess of ten percent of its normal body weight (when it is not due to fluid loss), you should be concerned. There are many things that can cause weight loss, including anorexia, the cat's quality of food, and/or chronic disease.

It is important to understand a severe case of weight loss will affect many of the cat's body system, but often it will depend on the cause and severity of the underlying medical condition.

Weight loss and cachexia can affect both dogs and cats. If you would like to learn more about how this condition affects dogs please visit this page in the PetMD pet health library.

Why is My Cat Losing Weight?

There are many factors which cause your cat to lost weight, including:

  • Fever
  • Anorexia
  • Cancer
  • Intestinal tumors
  • Pregnancy or nursing
  • Insufficient calorie intake
  • Prolonged exposure to cold
  • Paralysis of the esophagus
  • Organ failure (heart, liver, kidney)
  • Chronic blood loss (hemorrhaging)
  • The quality of the food (i.e., its taste, freshness)
  • Chronic protein-losing intestinal disorder
  • Blockages in stomach/gut (gastrointestinal obstructions)
  • Surgical removal (resection) of segments of bowel
  • Skin lesions that ooze and cause loss of protein
  • Disorders of the central nervous system that interfere with eating or appetite
  • Neurologic disorders that make it difficult to pick up or swallow food

Other causes of weight loss include various diseases and types of infections such as:


Your veterinarian will begin with a variety of diagnostic tests to find the underlying cause for your cat's weight loss. After an initial health assessment, your veterinarian may use one or more of the following tests:

  • Ultrasound of the abdomen
  • Intestinal endoscopy and biopsy
  • Exploratory surgery (laparotomy)
  • Fecal studies to look for chronic intestinal parasites
  • Tests to evaluate the condition of the pancreas
  • Bile acids test to evaluate liver function
  • Hormone assays to look for endocrine disorders
  • Chest and abdominal x-rays to observe heart, lungs, and abdominal organs
  • Complete blood count (CBC) to look for infection, inflammation, leukemia, anemia, and other blood disorders
  • A biochemical profile that will evaluate kidney, liver, and pancreas function, and the status of blood proteins, blood sugar, and electrolytes
  • Urinalysis to determine kidney function, to look for infections/protein loss from the kidneys, and to determine hydration status

  Next >