Defined as abnormally frequent and liquid fecal discharges, diarrhea is a very common condition that can range in severity from a mild inconvenience to a serious condition in which the animal becomes very sick and dehydrated.
Diarrhea can be classified as being acute in onset, meaning that the symptoms come on quickly and last no more than a week. Or, diarrhea can be chronic, lasting for several weeks to months. Dogs and cats with chronic diarrhea may have periods in which the condition gets better, but then grows worse again.
Diarrhea also is classified as being small bowel or large bowel in origin. Small bowel diarrhea means that the diarrhea is being caused by something damaging or irritating the stomach or small intestines. Large bowel diarrhea means that the large intestines or colon are similarly being irritated or damaged.
There are numerous causes of diarrhea. Eating rotten foods or trash, a sudden change in diet, a high-fat diet, viruses, bacteria, parasites, drugs, and cancer may cause it. Typically, animals with acute diarrhea that are not dehydrated or sick are treated symptomatically. Dogs and cats with severe or chronic diarrhea require a series of diagnostic tests to determine and treat the underlying cause. In certain cats, chronic diarrhea will be difficult to diagnose and to cure.
