What Tests Are Done For Unexplained Weight Loss in Dogs?

What could be causing my dog to lose weight?

Weight loss can be due to simple feeding and nutritional issues, or it can be due to a variety of medical conditions that cause indigestion, reduced nutrient absorption, or loss of nutrients from the body.

Diet problems: When a dog's diet does not contain enough energy to meet the body's needs, weight loss occurs. This could mean that the dog is simply not getting enough food or is eating poor-quality food, but it could also mean that the dog has unusually high energy needs, such as rapid growth, pregnancy, or vigorous physical activity. For example, young active puppies need extra energy and specific nutrients for growth and development; they can easily be underweight if fed only an adult diet. Likewise, active retrievers with high energy needs will need to eat more food than dogs on a leash to maintain a good weight. Any dog fed a low-quality diet may be at risk for weight loss due to nutritionally incomplete or indigestible components. Your veterinarian can provide your dog with guidance on the best food and how much to feed.

Diseases and medical conditions: including difficulty chewing and swallowing food; diseases such as Addison's disease; parasitic, infectious, kidney, heart, liver, pancreatic or intestinal diseases; and cancer.

How can we determine the cause of a dog's weight loss?

Finding the cause of your dog's weight loss usually begins with a complete medical history and physical examination. The dog's medical history includes details on the amount and quality of food being fed, changes in appetite and activity, changes in thirst or urination, and other signs of illness such as vomiting or diarrhea.

The physical examination includes examining the entire dog, listening to the heart and lungs with a stethoscope, and palpating the abdomen (softly squeezing or stimulating the abdomen with fingertips to identify abnormalities in the body). A complete physical examination may provide clues about the cause of weight loss; for example, a puppy with a "pot-bellied" appearance may have intestinal parasites; a dog with abnormal heart or lung sounds may have heart disease.

The cause of your weight loss may not be obvious at a physical exam, and your veterinarian may recommend screening tests. These are a series of simple tests that provide information about your pet's overall health and may provide further clues about potential problems. In pets with weight loss, the most common screening tests include: CBC (complete blood count), serum biochemical profile, urinalysis, and parasite testing. Based on the results of these screening tests, additional specific tests may be recommended.

What might these screening tests indicate?

bloodsmear_cliented(a) Complete blood count: This is a simple blood test that provides information about the different cell types in the blood. These include red blood cells that carry oxygen to tissues, white blood cells that fight infection and respond to inflammation, and platelets that help blood clot. CBC provides detailed information about the number, size, and shape of various cell types and determines whether abnormal cells are present in the circulation.

In dogs with weight loss, examples of changes seen on the CBC may include:

anemia. This means that the number of red blood cells and hemoglobin in the blood is lower than normal. Anemia can be found in many diseases, including those associated with weight loss such as intestinal parasites, intestinal bleeding, Addison's disease, liver disease, kidney disease, and cancer.

Changes in the appearance of red blood cells. For example, small, pale red blood cells indicate iron deficiency, which may indicate malnutrition, parasites, intestinal bleeding, or kidney bleeding.

The number of white blood cells increases. This may indicate the presence of underlying inflammation or infectious disease.

Abnormal white blood cells. The presence of atypical or abnormal white blood cells may indicate underlying bone marrow disease or cancer.

(b) Serum biochemical profile refers to the chemical analysis of serum (the liquid portion of blood). There are many substances in serum, including proteins, enzymes, fats, sugars, hormones, electrolytes, etc. Measuring the levels of various substances in the blood can provide information about the health of body organs and tissues such as the liver, kidneys and kidneys. pancreas and helps detect diabetes.

Some examples of changes in serum biochemical profiles that may help explain weight loss in dogs might include:

Abnormally high levels of the liver-related enzymes alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma glutamyltransferase (GGT) - have been associated with liver damage.

Elevated blood sugar - may be a sign of underlying diabetes or "sugar" diabetes.

Increased kidney values - indicates kidney disease.

Low albumin (a blood protein) - has been linked to a variety of conditions that lead to weight loss, including liver failure, kidney disease, blood loss, intestinal disease, liver shunts, pancreatic insufficiency, and more.

Altered Electrolytes - Electrolytes are salts and minerals in the blood. Changes in electrolytes, especially sodium and potassium, are common in Addison's disease, a disorder associated with weight loss.

(c) Urinalysis tests the chemical and physical properties of urine. Urinalysis is important in any sick animal and necessary for proper interpretation of serum biochemical profiles, especially in pets with kidney disease or diabetes.

In dogs with weight loss, examples of changes seen in a urinalysis may include:

Increased protein levels - linked to kidney disease, indicating protein is being lost from the body

Blood - Indicates bleeding from the kidneys or urinary system.

White blood cells and white blood cell casts (tubular clusters of white blood cells) - suggest a bacterial infection of the kidneys.

Large amounts of glucose - diabetes may be present.

(d) Parasite testing: Intestinal parasites or "worms" are a common cause of weight loss, especially in very young puppies. Testing for parasite eggs in fresh stool samples is an important screening test, and simple stool flotation is usually the first test performed. This involves taking a small sample of fresh stool and mixing it with a solution that causes the parasite eggs to float to the top of the sample. Eggs are collected and examined under a microscope to determine which parasites are present and how many there may be. There are many other parasite tests, and your veterinarian may recommend additional tests.

What additional tests might be recommended to investigate weight loss?

The need for additional testing will depend on the medical history, physical examination, and the results of the initial screening tests. Given the many reasons for weight loss, there is an equally long list of possible tests. Some of the more common professional tests include:

ACTH stimulation test - confirmed Addison's disease

Serum fructosamine - confirms diabetes (sugar diabetes); this is more common in cats than in dogs

Serum trypsin-like immunoreactivity test - if decreased pancreatic function is suspected

Serum Bile Acid Test - Assess Liver Function

Urine protein/creatinine ratio - to determine if there is significant urinary protein loss

X-ray or ultrasound - to look for tumors and to evaluate organs in the chest or abdominal cavity

Fine needle aspiration or other biopsy techniques - to check for tumors or enlarged organs

Cardiac testing - heartworm test, imaging, ProBNP blood test, EKG, etc. - if abnormalities in heart size, heart rate, rhythm or sound are found.

Detect specific infectious diseases.