Weight Loss in Dogs

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Weight loss is a physical condition that results from a negative caloric balance. This usually occurs when the body uses and/or excretes essential nutrients faster than it can consume them. Essentially more calories are being burned than are being taken in. Weight loss is considered clinically important when it exceeds 10 percent of the normal body weight and is not associated with fluid loss.

During weight loss, the appetite may be normal, increased or decreased.

What to Watch For

  • Weight loss
  • Loss of body condition
  • Loss of muscle mass
  • Poor hair coat
  • Diarrhea
  • Vomiting
  • Regurgitation
  • Difficulty swallowing
  • Coprophagia (eating one's own stool)

    Causes

    There are many reasons for loss of weight. Some of these include:

  • Dietary causes
  • Lack of appetite (anorexia)
  • Disorders related to poor absorption of nutrients
  • Disorders related to poor digestion
  • Metabolic disorders
  • Excessive nutrient loss
  • Neuromuscular diseases
  • Excessive use of calories
  • Cancer
  • Heart disease

    Diagnosis

    Confirmation of weight loss is necessary. A review of the animal's former body weight(s) is essential. Once weight loss has been documented, a thorough history and physical examination, in addition to appropriate diagnostic tests are indicated to determine a cause of the weight loss. Initial diagnostic tests may include:

  • Stool examination
  • Complete blood count (CBC)
  • Biochemical profile
  • Urinalysis
  • Chest and abdominal X-rays

    Treatment

    Your veterinarian may make several recommendations for the treatment of weight loss prior to instituting a full diagnostic work up. Such treatment is usually administered on an outpatient basis.

  • Sufficient calories in the form of adequate amounts of an appropriate, high-quality diet
  • Force-feeding
  • Appetite stimulants
  • Supplementation with vitamins and minerals for severely malnourished patients
  • Parenteral (intravenous) nutrition for patients who cannot take food orally
  • Comfortable and stress-free environment, especially when eating
  • An appropriate exercise regime

    Home Care

    Administer prescribed diets and medications precisely as directed. Periodically, weigh and record your pet's weight. Contact your veterinarian if there is any change in body weight.

    • Causes of weight loss vary markedly from intentional restriction of calories in order to reduce weight in an obese patient, to weight loss associated with life-threatening illness.

    Weight loss is a physical condition that results from a negative caloric balance, as when metabolic utilization and excretion of essential nutrients exceed the caloric intake. Weight loss is considered clinically important when it exceeds 10 percent of the normal body weight and is not associated with fluid loss.

    Weight loss can result from many different mechanisms that share the common feature of insufficient caloric intake or availability to meet metabolic needs. Causes vary markedly from intentional restriction of calories in order to reduce weight in an obese patient, to weight loss associated with life threatening illness.

    Historical information is very important, especially regarding type of diet, duration and environment of storage of diet, the patient's daily activity and, environment, the presence of pregnancy, appetite, signs of gastrointestinal disease (vomiting, diarrhea, regurgitation), or signs of any specific illness.

    There are several disorders or situations that need to be considered when evaluating patients for weight loss. These include:

    Dietary Causes

  • Insufficient quantity of food – not enough calories
  • Poor or inadequate quality of food
  • Decreased palatability (taste) of food
  • Spoiled food
  • Prolonged storage of food with deterioration of nutrients

    Anorexia

    This is often seen with many disorders and diseases.

    Malabsorptive Disorders (poor intestinal absorption)

  • Inflammatory bowel disease (IBD) is a microscopic accumulation of inflammatory cells into the intestinal wall. The cause is unknown, although it is thought to have an immune basis. Diarrhea and weight loss are commonly seen with the disorder.

  • Lymphangiectasia is a chronic protein-losing intestinal disorder that arises from congestion and dysfunction of lymph-carrying structures in the intestines.

  • Intestinal parasitism is most common in younger animals or animals that are housed in crowded and/or unsanitary conditions. It may involve roundworms, hookworms, whipworms, coccidiosis, and giardiasis.

  • Chronic infections of the bowel may lead to malabsorption. Examples include fungal infections and bacterial overgrowth.

  • Infiltrative tumors of the intestine may affect the intake of calories.

  • Gastrointestinal obstructions can prevent adequate absorption of nutrients and result in nutrient loss from vomiting and diarrhea.

  • Surgical resection of large segments of bowel can greatly decrease the overall absorptive surface of the intestines.

  • Maldigestive Disorders (inadequate break down/processing of food)

  • Exocrine pancreatic insufficiency (EPI) is a condition where the pancreas does not produce sufficient enzymes to break down food.

  • A lack of bile salts due to liver or gall bladder disease affects digestion and absorption.

    Metabolic Disorders

  • Various forms of organ failure (e.g. heart, liver, kidney)

  • Hypoadrenocorticism (Addison's disease) from an insufficient production of adrenal hormones.

  • Diabetes mellitus or sugar diabetes, which decreases the ability of the body to use sugar or glucose in the diet

  • Hyperthyroidism, where increased metabolism occurs secondary to increased out put of thyroid hormone

    Excessive Nutrient Loss

  • Protein losing enteropathy (PLE), a group of diseases characterized by excessive loss of proteins into the gastrointestinal tract

  • Protein losing nephropathies, which involve protein loss through the kidneys

  • Chronic hemorrhaging from the skin or intestinal tract, which results in loss of proteins

  • Extensive skin lesions or burns that ooze serum and increase the loss of protein from the body

    Neuromuscular Diseases

  • Primarily disorders of the central nervous system (brain and spinal cord) that render the animal unable to eat or cause them to loose their appetite

  • Paralysis of the esophagus

  • Neurologic disorders that affect the ability to pick up food or swallow food

    Excessive Use of Calories

  • Increased physical activity
  • Prolonged exposure to a cold environment
  • Pregnancy or lactation (nursing)
  • Fever or inflammation
  • Cancer

    Chronic Infections

  • Bacterial infections
  • Viral infections
  • Fungal infections
  • Mixed infections

  • Diagnosis In-depth

    Certain diagnostic tests must be performed to reach a definitive diagnosis of an underlying cause of weight loss. A thorough work-up begins with a set of broad tests that assess the overall health of the animal. More specific diagnostics are then performed, depending on the results of the initial tests. The following tests should be considered when working up the patient with weight loss:

  • Multiple fecal studies (flotation, direct smear and zinc sulfate suspension) are important to rule out chronic intestinal parasitism.

  • A complete blood count (CBC) evaluates the presence of infection, inflammation, leukemias, anemia, and other blood disorders.

  • A biochemical profile evaluates kidney, liver, and pancreas function, as well as the status of blood proteins, blood sugar, electrolytes.

  • A urinalysis assesses kidney function, helps detect infections of the urinary tract, protein loss from the kidneys and provide information on the hydration status of the patient.

  • Chest and abdominal radiographs (X-rays) evaluate the heart, lungs, and abdominal organs.

    Your veterinarian may recommend additional diagnostic tests to further investigate the cause of weight loss and to help determine appropriate therapy. These are selected on a case-by-case basis and include the following:

  • Serum trypsin-like immunoreactivity (TLI) is used to diagnose certain disorders of the pancreas that affect digestion and absorption.

  • Abdominal ultrasonography evaluates the abdominal organs and helps detect abnormal structures or masses that may be associated with weight loss.

  • Bile acids are paired blood tests obtained before and after a meal that evaluate liver function.

  • Various hormone assays may be indicated to rule out endocrine disorders.

  • Endoscopic examination and biopsy of the gastrointestinal tract may be recommended to search for diseases such as inflammatory bowel disease, gastrointestinal ulceration, neoplasia (cancer).

  • Exploratory laparotomy (abdominal exploratory surgery) allows close inspection of all abdominal structures. It also allows large biopsy samples to be obtained and may be indicated in difficult-to-diagnose cases.

    Therapy In-depth

    Your veterinarian may recommend one or more of the diagnostic tests described above. In the meantime, treatment of the symptoms might be needed, especially if the problem is severe. The following nonspecific treatments may be applicable to some pets with weight loss. These treatments may reduce the severity or provide some relief from the symptoms. Nonspecific therapy is not a substitute, however, for definitive treatment of the underlying disease responsible for your pet's condition.

  • If an underlying cause has been identified, treat or remove it if possible.

  • Provide sufficient caloric nutrition in the form of adequate amounts of an appropriate, high-quality diet.

  • Force-feeding may be tried in some cases.

  • Parenteral (intravenous) nutrition for patients who cannot take in food orally due to vomiting or regurgitation involves the use of gastric or intestinal feeding tubes, or the administration of liquid nutrients intravenously.

  • Supplementation with vitamins and minerals is necessary for malnourished animals.

  • Appetite stimulants may be useful in some cases.

    Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your pet does not rapidly improve and/or continues to lose weight.

    The necessity for patient monitoring and the methods required depends on the underlying cause of the weight loss; however, the patient should be weighed regularly and often.

    Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your pet. If your pet is not responding, also alert your veterinarian.


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