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Antibiotic-Responsive Diarrhea in Dogs

Veterinarians find it controversial to give antibiotics to treat diarrhea, but when antibiotics do resolve diarrhea, veterinarians speculate that the cause of this kind of diarrhea was from a small intestinal bacterial overgrowth. However, it is not known why some types of diarrhea are responsive to antibiotic while others are not. Current theories as to its cause focus on the possibility of immune dysregulation possibly associated with abnormal CD4+ T cells (immune cells), IgA plasma cells (antibodies), and cytokine (a chemical messenger) expression.

Symptoms and Types

• Small bowel diarrhea
• Lack of appetite
• Vomiting
• Weight loss
• Large amounts of diarrhea
• Large bowel diarrhea
• Straining to defecate
• Blood in the diarrhea
• Increased amount of defecation
• Increased intestinal sounds
• Gas

Causes

• Unknown, but certain bacteria are suspected:
• Clostridium perfringens
• Escherichia coli
• Lawsonia intracellularis

Diagnosis

You will need to give a thorough history of your dog's health, onset of symptoms, and possible incidents that might have preceded this condition. Your veterinarian will perform a complete physical exam on your dog, including a blood chemical profile, a complete blood count, an electrolyte panel and a urinalysis.

A fecal smear will be examined microscopically to rule out parasite infestation. Blood levels of cobalamin, or vitamin B12, may be low due to the diarrhea. X-rays should be taken to rule out other causes of diarrhea. Because there are several possible causes for diarrhea, your veterinarian will most likely use differential diagnosis to arrive at a conclusion. This process is guided by deeper inspection of the apparent outward symptoms, ruling out each of the more common causes until the correct disorder is settled upon and can be treated appropriately. To diagnose antibiotic-responsive diarrhea all other possible diagnoses will need to be ruled out. In addition, the diarrhea should improve and resolve when your dog is treated with antibiotics.