Weight Loss and Chronic Disease in Dogs

PetMD Editorial
Jul 2, 2008
Image: Photo Grapher / via Image Bank

Cachexia in Dogs

When should your dog’s weight loss concern you? The standard is when the loss exceeds ten percent of normal body weight (and when it is not due to fluid loss). There are many things that can cause weight loss, including chronic disease. It is important to understand this because the dog's entire body will probably be affected by the weight loss, and it ultimately depends on the cause and severity of the underlying medical condition.


  • Insufficient calorie intake
  • Poor quality of food
  • Taste (palatability) of food
  • Spoiled food/deterioration from prolonged storage
  • Reduced appetite (anorexia)
  • Inflammatory bowel disease
  • Chronic protein-losing intestinal disorder
  • Intestinal worms (parasites)
  • Chronic infections of the bowel
  • Tumors of the intestine
  • Blockages in stomach/gut (gastrointestinal obstructions)
  • Surgical removal (resection) of segments of bowel
  • Disease of the pancreas
  • Liver or gall bladder disease
  • Organ failure (heart, liver, kidney)
  • Addison’s disease
  • Diabetes
  • Hyperthyroidism
  • Chronic blood loss (hemorrhaging)
  • Skin lesions that ooze and cause loss of protein
  • Disorders of the central nervous system that interfere with eating or appetite
  • Paralysis of the esophagus
  • Neurologic disorders that make it difficult to pick up or swallow food
  • Increased physical activity
  • Prolonged exposure to cold
  • Pregnancy or nursing
  • Fever or inflammation
  • Cancer
  • Bacterial infections
  • Viral infections
  • Fungal infections


Your veterinarian will begin with a variety of diagnostic tests to find the underlying cause for the weight loss. After an initial health assessment, the following are some tests that might be recommended for your pet:

  • Fecal studies to look for chronic intestinal parasites
  • Complete blood count (CBC) to look for infection, inflammation, leukemia, anemia, and other blood disorders
  • A biochemical profile that will evaluate kidney, liver, and pancreas function, and the status of blood proteins, blood sugar, and electrolytes
  • Urinalysis to determine kidney function, to look for infections/protein loss from the kidneys, and to determine hydration status
  • Chest and abdominal x-rays to observe heart, lungs, and abdominal organs
  • Tests to evaluate the condition of the pancreas
  • Ultrasound of the abdomen
  • Bile acids test to evaluate liver function
  • Hormone assays to look for endocrine disorders
  • Using a scope to view the intestines (endoscopy) and biopsy
  • Exploratory surgery (laparotomy)

Related Posts

Weight Loss Coaching for Dogs

Weight Loss Coaching for Dogs

Jennifer Coates, DVM
May 30, 2013
Prebiotics and Weight Loss in Pets

Prebiotics and Weight Loss in Pets

Dr. Ken Tudor
Jul 18, 2012
Anemia Due to Chronic Kidney Disease in Dogs

Anemia Due to Chronic Kidney Disease in Dogs

Victoria Heuer
Apr 05, 2016