Acute Diarrhea
Acute diarrhea is a common clinical problem in veterinary practice. It is characterized by a sudden onset and
short duration (three weeks or less) of watery or watery-mucoid diarrhea. Occasionally the fecal material is also
overtly bloody.
Diarrhea results from excessive water content in the feces and is an important sign of intestinal diseases in the
dog. Diarrhea can affect your dog by causing extreme fluid loss, which leads to dehydration, electrolyte
disturbances, and/or acid-base imbalances.
General Causes
Dietary indiscretion (eating inappropriate food/material)
Infectious agents - bacterial, viral, fungal, protozoal, parasitic infections
Drugs and toxins
Intussusception (telescoping of the bowel on itself)
Intolerance of materials in the normal diet
Intestinal obstruction
Met
What to Watch For
Passage of loose, watery stools that persist for more than one day
A change in the color of the stool
The appearance of blood in the stool
Decreased appetite
Vomiting
Depression, lethargy
Fever
Acute diarrhea is often alarming, but may not be an emergency if your dog is still active, drinking and eating,
and is not vomiting. However, acute diarrhea associated with vomiting, lack of water intake, fever, depression,
or other symptoms should prompt a visit to your veterinarian.
Chronic Diarrhea
Diarrhea is defined as the rapid movement of fecal matter through the intestine resulting in poor absorption of
water, nutrients and electrolytes. With diarrhea the stools (bowel movements) become loose or runny. Chronic
diarrhea refers to diarrhea that persists for three or more weeks. Occasionally the fecal material may contain
fresh blood or mucus.
Chronic diarrhea is an important sign of intestinal disease in the dog. Persistent diarrhea can lead to weight loss
from poor digestion and loss of important nutrients. Chronic diarrhea can lead to loss of body condition,
development of a poor hair coat, and may also affect appetite and activity levels.
General Causes
Most causes of chronic diarrhea induce local irritation or structural abnormalities of the intestinal mucosa
(lining). There are numerous diseases and disorders that can lead to chronic diarrhea.
These include:
Infectious agents such as bacterial infections, protozoal agents, fungal infections, and intestinal parasites
Certain drugs and toxins
Inflammatory bowel disease, e.g. enteritis (inflammation of the small bowel) and colitis (inflammation of the
large bowel)
Dietary intolerance or food allergy
Gastrointestinal cancer
Partial obstruction (blockage) of the intestinal tract
Other systemic illnesses, such as liver disease, pancreatic diseases, kidney disease, etc.
Small intestinal bacterial overgrowth (SIBO)
Lymphangiectasia, and other disorders of malabsorption (inability to absorb food stuffs or cause proteins and
other materials to be lost in the feces)
Disorders of maldigestion (inability to digest food stuffs in the intestine)
Short bowel syndrome
Irritable bowel syndrome (spastic colon)
What to Watch For
Passage of loose, watery stools that persist for more than three weeks
A change in color of the stool
Blood in the stool
Mucus in the stool
Straining to defecate
Increased number of stools
Decreased appetite
Weight loss
Poor hair coat
Lethargy