Weight Loss and Chronic Disease in Dogs

A dog’s weight is something that normally fluctuates a bit depending on the amounts and quality of food offered and the amount of energy being expended. In some cases, you may even want your pet to lose weight, as being overweight can also shorten your pet’s life. A safe weight loss amount for overweight dogs is three to five percent of their weight per month. Fluctuations of more than ten percent of your pet’s weight are a cause for concern. Many chronic illnesses that affect canines can result in an unhealthy decline in weight.

Weight loss is a symptom commonly seen in dogs with chronic diseases. Changes to your dog’s eating behavior should be taken seriously, and your veterinarian should be involved as soon as possible.

The rib bones and backbone of a canine should not be visible in most cases as this indicates malnutrition related weight loss. Naturally thin breeds such as greyhounds and whippets may have somewhat visible ribs at a healthy weight for their breed. The weight loss in canines afflicted with chronic illnesses is often accompanied or preceded by other signs of malnutrition, such as: 

• Diarrhea
• Dull coat
• Eating feces
• Flaking skin and dandruff
• Hair loss
• Hard feces
• Higher rate of infection
• Lethargy
• Loss of muscle mass
• Loss of skin elasticity
• Vision problems
• Vomiting bile
• Weakened bones and teeth

Types:

There are many chronic diseases and disorders that include weight loss as a prominent symptom. These can include, but are not limited to, disorders such as:

• Addison’s disease
• Broken or infected teeth
• Chronic fungal or bacterial infection
• Chronic hepatitis
• Chronic renal failure
• Chronic diarrhea
• Diabetes
• Exocrine pancreatic insufficiency (EPI)
• Gallbladder disease
• Heart disease
• Hyperthyroidism
• Inflammatory bowel disease
• Lymphangiectasia (a chronic intestinal disorder)
• Neurologic disorders that affect the ability to pick up food or swallow food
• Paralysis of the esophagus
• Parasitic infestation (Giardia, hookworm, roundworm, tapeworm, whipworm)
• Protein-losing enteropathy (PLE)
• Stomach ulcers
• Surgical re-sectioning of the bowel
• Tumors

• Poor appetite and refusal to eat are generally signs of trouble in dogs
• When the patient has lost the desire to eat it is called anorexia and this can be caused by chronic pain, loss of the sense of smell, or nausea
• Disorders in which food is ingested but the dog’s digestive system does not properly carry out its process
• Examples are maldigestive disorders such as exocrine pancreatic insufficiency work by interfering with the body's ability to break down food into usable nutrients
• Others include malabsorptive disorders are diseases such as inflammatory bowel disease, lymphangiectasia or severe parasitic infestation that inhibit the body's ability to absorb nutrients from the intestinal tract
• Increased caloric demand- Seen in chronic diseases such as hyperthyroidism, chronic infection, or cancer
• Tumors in the mouth or conditions like paralysis of the esophagus or gastric outflow obstruction may make it painful or impossible to eat normally
• Dogs with pseudo-anorexia have a desire to eat, but are unable to due to an underlying condition such as broken teeth, muscle wasting, or a nervous system disorder that affects the motions of chewing and swallowing

Your veterinarian will ask you for a history of the weight loss. Questions regarding your dog’s diet and appetite will be asked, as well as inquiries about whether any vomiting or diarrhea has been recently observed. A physical examination will also be done to help discover any underlying cause to the reduction in weight. Special attention will be paid to the mouth area to check the health of the teeth and jaw structure. The preliminary lab work will likely consist of a complete blood count (CBC), blood chemistry panel, thyroid hormone test, urinalysis and a fecal examination. The veterinarian may also recommend a tick titer test to check for tick-borne illnesses. Depending on the results of the physical examination and the lab work, additional tests may be recommended. X-rays and ultrasound imaging can assist the veterinarian in determining if there is any swelling or displacement of internal organs. It will also help detect if there are any growths or tumors that are developing internally. A barium study may also be done to further determine if there are any internal blockages or cancers.

If the patient is showing symptoms of severe dehydration or weakness due to malnutrition, your pet may be checked into the animal hospital for supportive treatment such as IV Fluids or pain mitigation. As there are several possible underlying conditions, your veterinarian will only be able to discern a treatment plan once the blood tests have been completed. The treatments can vary greatly between cases as can the prognosis. With many chronic diseases nausea and vomiting can become a problem. If vomiting related to the chronic disorder is preventing the dog from getting the nutrition it needs medications to combat the symptoms may be given. These medications could include anti-emetics, gastric protectants or corticosteroids. In some circumstances, it would also be appropriate for your veterinarian to prescribe a short-term appetite stimulant. There are cases where the patient still refuses to eat or is prevented from eating due to the nature of the underlying condition. At that point it may be necessary for your veterinarian to place a feeding tube into the esophagus, stomach, or even directly into the small intestine.

Once your pet has returned home you will need to make sure that you make any changes to your dog’s diet or environment as recommended by your veterinarian. Keeping your pet warm is also crucial. Dogs that have developed malnutrition tend to lack body fat therefore get cold much more quickly which can lead to shivering, and shivering uses lots of calories, and the malnourished body needs to hold on to all of the calories it can in order to heal. A nice warm dog bed will help ensure that your pet has the best chance for recovery. Weighing your dog on a regular basis will give you a record of his or her progress which will be needed by your veterinarian. Severe weight loss and malnutrition can lead to the development of arthritis due to the deterioration of the synovial fluid that provides the cushioning for the joints.