Many diseases and disorders can cause weight loss.Unintended weight loss without loss of fluid may accompany serious illness. Veterinarians consider weight loss in animals to potentially signal illness when it exceeds 10 percent of previously stable body weight in normally hydrated animals. Thus weight loss is associated with a reduction in the fat stores and muscle mass of the animal’s body. Weight loss occurs when the body’s metabolic requirements, measured in calories (technically kilocalories), exceed the usable calories derived from food. When an animal (or a human, for that matter) needs to lose weight, reducing the amount or changing the type of food eaten–so that the number of calories consumed is less than the body needs– will result in weight loss. Such weight-reduction diets are designed to reduce stored body fat only and not other tissues (especially muscle). This is controlled weight loss and is supervised by a clinician. There are many diseases associated with uncontrolled or unintended weight loss. In some of these diseases starvation actually occurs even if the affected animal is eating normally or excessively. As fat stores are depleted, muscle begins to breakdown to provide protein for energy production and restorative processes. Additionally, muscle also breaks down when the body’s protein requirements are not being met through the diet or digestive processes. In such situations, a negative nitrogen balance is said to exist, which is a sign of starvation and a very serious underlying disease. Several physiologic mechanisms exist that produce disease-associated weight loss. Some feline diseases significantly increase energy (calorie) requirements. Without a compensatory increase in food, the affected cat loses weight. Metabolic, malignant (cancerous) and infectious diseases fit this category. Common examples include diabetes mellitus, kidney disease or failure, and hyperthyroidism; lymphoma and other cancers; feline immunodeficiency virus or feline leukemia virus and other infectious diseases. Sustained exposure to a cold environment can also raise energy needs as the body shivers to produce heat. These processes can lead to weight loss in spite of a normal or, even, increased appetite. Diets with insufficient calories or poor nutrient quality relative to the cat’s normal metabolic requirements will cause weight loss. Consulting with a veterinarian about proper diet and amounts to be fed and then following the doctor’s instructions will eliminate this cause of unintended weight loss in healthy cats. Insufficient food intake, where the affected cat refuses to eat or cannot eat, has many causes. Anorexia (loss of appetite), dysphagia (difficulty swallowing), regurgitation, nausea and vomiting may limit food intake and nutrient availability. Many diseases of cats produce these nonspecific signs. Cats won’t eat if they cannot smell their food; so problems affecting the sense of smell, including respiratory diseases, infections, and allergies, among others may be associated with weight loss. Dental problems that make chewing difficult may also prevent normal food intake. Food with low “taste appeal,” especially to finicky cats, will contribute to weight loss as well. Disorders where consumed food is not properly absorbed into the body or is not converted into energy will also cause the affected animal to lose weight. Intestinal parasites, inflammatory disorders of the intestines, and tumors can block the normal absorption of nutrients and fluids from the stomach and intestines. Pancreatic and liver diseases can disrupt production and secretion of enzymes and other substances needed to process nutrients. Gastrointestinal ailments in which nutrients are eliminated from the body before they can be absorbed and converted into energy can result in profound weight loss. Severe persistent vomiting and diarrhea associated with various diseases can result in loss of nutrients necessary for energy production. Liver, kidney and gastrointestinal diseases may result in loss of protein. Glucose is lost through urinary excretion in diabetes mellitus; protein is lost with certain diseases of the kidney’s glomerular apparatus. When a cat or other animal with a history of unexplained weight loss is presented to a veterinarian, the doctor will take a history and perform a physical examination in order to develop a list of possible underlying diseases. Then appropriate laboratory tests and other studies will be undertaken to narrow the field of possible causes. Tests typically include complete blood count, blood chemistry, and urinalysis. Tests for intestinal and other parasites, as well as for bacterial, viral, and fungal diseases may be needed. Radiographs (x-rays) and ultrasound scans may be helpful in evaluating the status of the heart, liver, and other organs and may help reveal the presence of abnormal growths. In some cases biopsy or fine-needle-aspirate tissue sampling techniques may be needed to obtain tissue samples for microscopic evaluation. Endoscopy might be needed to visualize and sample various parts of the gastrointestinal tract. Treatment is directed at the underlying cause of the weight loss. If recovery follows, restoration of weight is possible and likely. Debilitated animals may need supportive treatment to restore fluid loss, force feeding, or hyperalimentation therapy, where nutrients are given parenterally (intravenously), to help maintain positive nitrogen balance.
Hours:
Mon, Wed, Fri: 9am – 4pm
Tue, Thur: 9am – 7pm
Sat: 8am – 12pm