Chronic Diarrhea in Dogs
Dr. Bari Spielman
Veterinary care includes diagnostic tests and subsequent treatment recommendations. Some, if not all, of the following tests may be necessary to diagnose the cause of chronic diarrhea: Complete medical history and physical examination are helpful in instituting an appropriate diagnostic plan.
Multiple fecal studies (flotation, smear and cytology, zinc sulfate test) to search for intestinal parasites, protozoal parasites, and bacteria should be performed on all patients with chronic diarrhea.
A complete blood count (CBC) evaluates the animal for infection, inflammation and anemia.
A biochemical profile assesses kidney, liver, and pancreas function, as well as electrolyte status, protein levels, blood sugar, etc.
A urinalysis helps to evaluate kidney function and the level of hydration of the animal.
Abdominal radiographs (X-rays) assess the abdominal organs and may detect the presence of a foreign body, obstruction, or tumor.
Thoracic (chest) radiographs are recommended in geriatric patients and animals who may have cancer, to detect metastasis (spread of cancer) to the lungs.
Bacterial fecal cultures may be recommended in some cases.
Serologic tests may be performed for fungal diseases that cause chronic diarrhea.
Serum trypsin-like immunoreactivity (TLI) , serum folate, and cobalamin are blood tests that help assess digestion and absorption within the small intestines.
Depending upon the clinical signs and the results of the above tests, your veterinarian may recommend further testing. These tests are chosen on a case-by-case basis:
Abdominal ultrasonography helps to evaluate the size, shape and consistency of the abdominal organs. It may detect thickening of the intestines, masses, partial obstructions and other organ abnormalities. Abnormal organs, lymph nodes and masses may be sampled with a needle or biopsy instrument with the guidance of ultrasound. This test may require referral of your animal to a veterinary specialist in internal medicine or radiology.
An upper gastrointestinal (GI) barium series helps assess the passage of food stuffs through the upper intestine. A barium enema helps assess the lining of the lower bowel. The two tests may detect motility disorders, thickening of the bowel, twisting or displacement of the bowel, obstructions, strictures and masses of the intestines. They may also be helpful to detect foreign bodies that are not seen on plain radiographs.
Endoscopic examination and biopsy are often required for diagnosing the cause of chronic diarrhea. Endoscopy involves passage of a flexible viewing scope into the stomach and small intestines. Colonoscopy involves passage of either a flexible or rigid scope into the rectum and colon. Small biopsies, as well as samples for cytology and culture are obtained through the scope
A blood lead level may be performed on any dog with chronic intestinal signs, especially if their environment is suggestive of exposure to lead, if there is material showing up on plain x-rays that resembles lead in the intestines, or if certain characteristic changes of lead poisoning are seen on the complete blood count.
Serum bile acid tests may be performed in animals with evidence of liver disease.
Exploratory abdominal surgery (laparotomy) is often considered if other diagnostic tests are inconclusive, or if a disease is suspected that requires corrective surgery. It is sometimes needed to reach a conclusive diagnosis.