Diagnosing and treating chronic diarrhea in dogs can be a difficult and arduous task. There are many potential causes, and isolating the problem can take time and effort. However, it’s crucial for your dog’s overall health to correctly manage chronic diarrhea.
Unlike acute cases of diarrhea, where intestinal upset occurs suddenly and resolves within several days with treatment, chronic diarrhea occurs over weeks or even months. Chronic diarrhea in dogs is characterized by a change in the frequency, consistency, and volume of fecal material for more than three weeks. These episodes may be episodic, where the stool may become firm for a period, then become soft and unformed again without any obvious cause.
The most common symptom of chronic diarrhea in dogs is diarrhea of varying severity. Chronic diarrhea can be categorized into two main groups: diseases of the small bowel, and diseases of the large bowel.
Symptoms of Small vs. Large Bowel Disease
Symptoms of Small Bowel Intestinal Disease:
- Larger volume of feces than normal
- Dogs will pass feces more frequently than normal (2-4 times a day)
- Weight loss
- Feces may appear darker than normal or tar-colored
- Dogs may have excessive gas
- Dogs may also have episodes of vomiting
Symptoms of Large Bowel Intestinal Disease:
- Smaller volume of feces than normal
- Dog will pass feces significantly more frequently than normal (4 or more times a day)
- Dogs may strain to defecate, appearing urgent
- Feces may appear to contain flecks of blood
- Feces may contain mucus
Veterinary care is necessary for any dog suffering from chronic diarrhea. Based on your dog’s symptoms and physical exam, your veterinarian may recommend various tests to help determine the underlying cause of the intestinal disease.
Common Causes of Small Bowel Intestinal Disease in Dogs:
Inflammatory Bowel Disease (IBD): In affected dogs, inflammatory cells take over the intestines, leading to scar tissue throughout the digestive system. Dogs with IBD often have a bad hair coat due to poor absorption of nutrients. Diagnosis of IBD can be difficult, and treatment usually involves reducing inflammation and changing the diet to make it easier to digest.
Parasite Infection: Giardia and other intestinal parasites can cause chronic diarrhea in dogs. Fecal examination and antigen testing can diagnose parasites, and treatment typically resolves the issue.
Bacterial Infection: Bacteria such as Salmonella or Clostridium perfringens can cause severe chronic diarrhea. Fecal cultures help identify these bacteria, and long-term treatment can prevent recurrence.
Dietary Sensitivity: Dogs can develop allergies or intolerances to certain ingredients in their food, similar to lactose intolerance in humans. This chronic inflammation in the intestinal tract requires identifying the causative ingredient(s) and switching to a diet that doesn’t cause sensitivity.
Liver Disease: Chronic diarrhea can be an early symptom of liver disease before diagnosis is made.
Pancreatitis: This inflammation of the pancreas, which can occur acutely or chronically, decreases digestive enzyme production. Diarrhea, abdominal pain, vomiting, and poor appetite are common symptoms. It’s difficult to diagnose because many gastrointestinal problems share similar symptoms.
Hypoadrenocorticism (Addison’s Disease): An endocrine disorder that decreases cortisol production, leading to stress response issues. Chronic diarrhea, along with lethargy, vomiting, anorexia, weight loss, and increased thirst/urination, can indicate Addison’s disease, especially in predisposed breeds.
Additional Causes of Large Bowel Disease
Many causes of large bowel intestinal disease are similar to those of small bowel disease, including parasite infections, bacterial infections, and Addison’s disease. However, there are also other causes of large bowel diarrhea:
Dietary Changes: Switching to a new food too quickly can cause both acute and chronic diarrhea. Gradually introducing new food over 7-10 days can help prevent this problem.
Poorly Digestible or High-Fat Diets: These can cause chronic diarrhea as the body struggles to rid itself of undigested material. Long-term feeding of high-fat diets can also lead to pancreatitis.
Lymphosarcoma: This cancer typically affects the lymph nodes but can involve gastrointestinal symptoms. Dogs with gastrointestinal lymphosarcoma experience weight loss, lethargy, vomiting, diarrhea, abdominal discomfort, and concurrent illness in other systems.
In cases of chronic diarrhea, a veterinarian will perform a physical exam and may recommend various tests based on clinical signs and history. Fecal examinations (e.g., fecal flotation or cytology) can help identify parasites or bacterial infections. A complete blood count and blood chemistry analysis provide valuable insight into liver disease, pancreatitis, lymphosarcoma, and Addison’s disease.
Abdominal radiographs may be taken to rule out intestinal obstructions or masses that could be causing the diarrhea.
If no obvious cause is found, an abdominal ultrasound may be recommended. This can check for thickened bowel walls (indicating inflammatory bowel disease) or assess for intestinal masses, foreign bodies, or evaluate the health of the intestinal tract.
Managing Chronic Diarrhea in Dogs
Treatment and success rates depend heavily on the underlying cause of the diarrhea. Determining the cause is crucial, as treatments can vary greatly. In some cases, total resolution of symptoms may not be possible, but with proper medical management, the condition can become well-controlled and manageable.
