Canine Diarrhea

Diarrhea indicates a problem in the intestines or colon. It is a symptom of some underlying disease. It can be caused by a viral or bacterial infection. It could also be caused by a disease of the intestine or colon wall; for example, cancer or inflammatory bowel disease. Other causes include foreign body ingestion or dietary indiscretion. Diarrhea can be mild and self limiting; or debilitating and life threatening. It is one of the more common illnesses a veterinarian is called upon to diagnose and treat.

How do I know if it is serious?

This question is best answered by your veterinarian after a thorough examination. If the pet is seriously debilitated, your veterinarian may need to take x-rays and run some lab tests. An examination of the stool for parasites is also indicated. After taking a history and interpreting the lab results your veterinarian can determine the cause of the diarrhea and start the appropriate treatment.

Why is the history important?

Knowing the dogs activities and whereabouts previous to the outbreak of diarrhea may help determine the cause. If the dog has been to a boarding kennel, grooming parlor, or even run away for a few hours, it may have contacted a virus from an other dog. If the dog has a history of getting in the garbage it may suggest the problem is due to an intestinal foreign body or ingestion of spoiled food. The history may suggest the problem is a simple one due to a different brand of dog food, or too many table scraps. If the problem has been going on for a long time this may indicate a chronic condition such as inflammatory bowel disease. The questions your veterinarian asks are designed to narrow down the many potential causes to a likely few.

What kinds of tests are used?

The most common test is a fecal flotation test. In this procedure the veterinary technician mixes a small amount of stool in a salt solution that helps to isolate intestinal parasites, or their eggs. By looking at the solution under a microscope the technician can determine if parasites are playing a role in causing the diarrhea. A similar procedure called the fecal direct smear involves examining the stool directly under the microscope to look for fragile parasites that might be otherwise be missed. Sometimes the stool is cultured to see if bacteria is the cause of the problem. Another type of test may be done on the stool sample to look for parvo virus.

X-rays are another useful tool for diagnosing the cause of diarrhea. By visualizing the abdominal organs, the veterinarian can look for a foreign body or tumor. Many times it is also necessary to do a contrast study. In this procedure the pet is given Barium through a stomach tube, and x-rays are taken as the barium moves through the stomach and intestines to the colon. This procedure helps to identify small objects or tumors that are not seen on regular films.

Some veterinarians may use an ultrasound to accomplish what the x-ray does. An ultrasound is particularly helpful in seeing very subtle changes in the stomach or intestine that an x-ray can not detect.

Endoscopy may be recommended in chronic cases of diarrhea. This allows the veterinarian to see the stomach and intestines from the inside. It also enables the veterinarian to take a biopsy, or retrieve small foreign bodies.

How is diarrhea treated?

The treatment depend on the cause. Deworming medication will be all that is needed to treat the problem if it is due to a parasite. Diarrhea due to a mild intestinal virus, or dietary change, may be treated with kaopectate and a boiled rice diet. Diarrhea caused by Parvo virus is life threatening and will require aggressive intravenous fluid therapy coupled with antibiotics and other supportive care. Inflammatory bowel disease often responds to antibiotics and anti inflammatory drugs. Special diets will also help some animals with chronic colitis. Surgery is usually needed when the diarrhea is the result of a foreign body or tumor. Your veterinarian will recommend the best course of treatment after determining the cause.

by William M. Fraser, D.V.M.

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