Page 742 - Problem-Based Feline Medicine

33. The cat with signs of chronic small

bowel diarrhea

Debra L Zoran

KEY SIGNS
● Loose to watery feces.
● ± Melena.
● No mucus or fresh blood.
● > 3 weeks duration.

MECHANISM?
● Diarrhea may be defined as a change in the frequency, consistency or volume of bowel
movements.
● The four recognized pathophysiologic mechanisms that cause diarrhea include osmotic,
secretory, increased permeability and altered motility.
● Osmotic diarrhea and conditions causing increased permeability are believed to be the most
common causes of diarrhea.
● Classification of diarrhea by characteristics that tend to be more prevalent in small vs. large
intestinal disease is a helpful way to develop an appropriate diagnostic and treatment regimen.
Small bowel diarrhea is characterized by:
● Loose to watery feces.
● Increased volume of feces.
● Normal to increased frequency of defecation.
● No or little straining or tenesmus associated with defecation.
● If blood is present in feces it occurs as melena.
● No increase in mucus on the feces.
● Weight loss and vomiting are commonly observed concurrently.
WHERE?
● The small intestinal tract (duodenum, jejunum and ileum) is the site of origin of the diarrhea.
However, diseases in other body systems may cause diarrhea in an otherwise normal
intestinal tract (e.g. liver disease, hyperthyroidism, etc.).

WHAT?
● Chronic small bowel diarrhea is a clinical sign that should be aggressively evaluated to
determine its cause.
● Cats with chronic diarrhea of small intestinal origin may have any of a number of GI or
systemic diseases or disorders, but metabolic (hyperthyroidism, renal or liver disease, etc.),
idiopathic (inflammatory bowel disease), neoplastic (lymphoma), and nutritional (food
allergy or intolerance) are common causes.

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