Clostridial Diarrhea and Colitis in Dogs

Clostridium perfringens is a common cause of diarrhea in our canine patients. Clostridium is a soil dwelling bacterium which can be cultured from the feces of many normal dogs. Under certain circumstances it overgrows the normal colonic bacteria and forms spores which produce an endo-toxin. The toxin causes an inflammation of the colon resulting in diarrhea. This begins as a watery and mucus covered diarrhea progressing to include some blood and can become very serious. Some dogs will experience intermittent and recurrent bouts of diarrhea while being completely fine in between. On presentation to the clinic these dogs are often happy and healthy, excepting for the history of chronic watery persistent diarrhea and straining. Any age or breed of dog can be affected.

Diagnosis always begins with a clinical examination of the dog and rule out other causes of diarrhea. Fecal testing is performed to eliminate other causes of infectious and parasitic infestations. Microscopic examination will readily demonstrate a huge overgrowth of sporulating clostridial bacteria. Fecal samples can be submitted to a veterinary laboratory for PCR testing which can specifically identify the Clostridium perfringens toxin.

Treatment entails the use of an antibiotic. Generally we begin with metronidazole or amoxicillin. These antibiotics are typically used for a period of 7 to 10 days if it is a first occurrence. For recurrent cases we significantly extend the time for which we use the antibiotics.

Probiotics are used in an attempt to improve the intestinal and colonic flora. We now have specific dog products available to us and these have proved helpful. Dietary management is very useful adjuvant and we may recommend a specific gastrointestinal diet. Fortunately many commercial veterinary prescription diets are available to us. Occasionally we might also recommend the use of specific home prepared diets.

The majority of clostridial colitis patients responded quickly to the use of antibiotics and recurrences are infrequent. However, a number of dogs seem to be particularly susceptible to recurrence once the antibiotics are ceased. Typically the cause is an underlying immune incompetence or bowel sensitivity on the part of the dog, and ongoing medication is required. Fortunately even for patients requiring ongoing medication, we find the antibiotics are well tolerated and a return to full health occurs shortly after a return to antibiotic treatment.