How to manage feline chronic diarrhea, Part I: Diagnosis

How to manage feline chronic diarrhea, Part I: Diagnosis

A combination of patient history, fecal analysis, and additional diagnostic tests will help you discover the cause of this all-too-common clinical sign.

Illustration by Laurie O'Keefe
An increase in the frequency and liquidity of bowel movements is an important sign of gastrointestinal (GI) disease in cats. Veterinarians are often consulted when diarrhea is associated with systemic illness or when it becomes persistent. When diarrhea occurs either intermittently or continuously for three weeks or more, it is considered a chronic condition. Chronic diarrhea in cats can be a diagnostic and therapeutic challenge, so we'll help you approach these cases logically and thoroughly. First we'll discuss which diagnostic tests are most helpful in cats with chronic diarrhea, and in the article that follows we'll cover drug and dietary treatments.


In evaluating cats with chronic diarrhea, first obtain a careful and complete history that includes signalment, vaccination and deworming history, and information about the cat's environment, recent travel, past medical problems or surgeries, current diet regimen plus recent changes, and current prescription medications and nutraceuticals. A thorough history may suggest extraintestinal disease or exposure to parasites, infectious agents, drugs, or toxins.

Table 1: Clinical Signs Associated with Diarrhea
Ask additional questions that focus on the diarrhea and elucidate the onset, duration, specific characteristics, and associated clinical signs. A description of the feces (color, volume, presence of blood or mucus), the frequency and urgency of defecation, and associated clinical signs (anorexia, weight loss, vomiting, tenesmus, dyschezia) may localize the problem to a specific region of the GI tract (Table 1). Also ask about response to any treatments or dietary changes to help identify aggravating or alleviating factors.


Thoroughly evaluate all body systems before focusing on the GI tract. You may identify a fever or detect evidence of weight loss, cachexia, dehydration, or other signs of systemic disease. Palpate the thyroid glands and perform an ophthalmic examination including fundic evaluation. Consider a rectal examination if the history suggests large bowel diarrhea or rectal or anal disease.

Abdominal palpation in cats is usually straightforward because most patients are small, and abdominal contents are often readily palpable. The best assessment is obtained by using the flats of your hands and fingers against the abdomen as opposed to your fingertips. Using intermittent pressure and release minimizes patient discomfort. Elevating the cat's front end helps position the cranial abdominal organs within reach. Abdominal palpation should be systematic and include the small and large bowel as well as the abdominal lymph nodes. Take note of intestinal location, size, pain, masses, thickening, and fluid or gas distention. The presence and severity of abnormalities determines how aggressive or conservative the next diagnostic steps should be.