Overview:

Weight loss isn't a disease in itself rather it is a sign of an underlying problem. There are generally two 'reasons' your cat loses weight. Stress or medical condition.

Veterinary attention should be sought if your cat is losing weight, so he can determine the cause.

Causes of weight loss in cats:

• Acute or chronic kidney failure

• Addison's disease

• Anorexia (loss of appetite)

• Cancer

• Coccidiosis

• Cryptosporidium

• Dental problems (stomatitis)

• Diabetes mellitus

• Dietary (inadequate amount of food, poor quality food)

• Exocrine pancreatic insufficiency

• Feline Immunodeficiency Virus

• Feline Infectious Anemia

• Feline Leukemia Virus

• Giardia

• Glomerulonephritis

• Heartworm

• Hepatic lipidosis

• Hypercalcemia

• Hyperthyroidism

• Hypertrophic cardiomyopathy

• Inflammatory Bowel Disease

• Liver disease

• Lymphosarcoma
  

• Pancreatitis

• Parasitic worms (heartworm)

• Pregnancy & lactation

• Stress (some possible causes of stress include; moving house, loss of companion, new pet/person in the house, hospitalisation, being boarded)

This list is by no means complete, there are also many other possible causes of weight loss in cats.

Signs of weight loss in cats:

Weight loss can be further split into 'polyphagic' which means progressive decrease in body weight in the presence of an increased appetite or just 'weight loss' which is a result of decreased appetite, increased activity, dehydration, decreased access to food, quality of food, pregnancy, lactation etc.

Other signs to look out for include;

• Anorexia (loss of appetite)
• Bad breath
• Changes in behaviour
• Increased appetite
• Increased thirst
• Increased urination
• Diarrhea
• Vomiting
• Loss of coat condition
• Depression

Diagnosing the problem:

Your veterinarian will perform a complete physical examination from you & obtain a medical history, including the cat's age & other symptoms you may have noticed.

Hyperthyroidism & diabetes are common causes in older cats & may be tested for first. Tests your veterinarian will commonly perform include;

• Abdominal x-ray or ultrasound
• Biochemical profile
• Blood tests to detect elevated levels of the hormones T3 & T4 are performed. Some cats with hyperthyroidism may show normal levels of these hormones in their blood test. If this is the case then a T3 suppression test may be performed. This involves taking a blood test to check the levels of T3 & T4, 7 oral doses of the thyroid hormone T3 & a blood test after the hormone was given. In a normal cat, the level of T4 will drop, in a cat with hyperthyroidism the T4 levels will stay the same or increase slightly.
• Complete blood count
• Urinalysis

Treatment of weight loss:

Treatment depends on the cause and is covered in more detail in the individual articles relating to specific diseases & disorders.

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