TL;DR: Chronic foul-smelling diarrhea in cats typically indicates malabsorption or infection and requires a veterinary appointment within a few days to prevent dehydration and weight loss.
What causes chronic foul-smelling diarrhea in my cat?
Chronic diarrhea is defined as loose or liquid stools lasting for three weeks or longer. When the odor is particularly pungent or foul, it often indicates that your cat is not properly digesting their food or may have an overgrowth of harmful bacteria or parasites like Giardia. It is a stressful situation for both you and your pet, but many causes are manageable with proper veterinary care and dietary adjustments.
Is my cat’s chronic diarrhea a medical emergency?
The urgency level for this condition is Medium. While usually not an immediate life-threatening emergency, you should schedule a veterinary appointment within the next few days to prevent:
- Long-term health decline
- Nutrient malabsorption
- Significant weight loss
- Severe dehydration, extreme lethargy, or persistent vomiting (which require immediate attention)
Why should I take a photo of my cat’s stool for the veterinarian?
Providing your veterinarian with a photograph of the stool can be incredibly helpful for triage. Visual evidence helps the clinical team speed up the diagnostic process by identifying:
- Specific color and consistency
- The presence of mucus or blood
- Differences between small-bowel and large-bowel issues
- Which diagnostic tests are most necessary for your cat
Clinical Context (Merck Veterinary Manual)
In cats presenting with chronic foul-smelling diarrhea, initial veterinary triage should include a complete history, physical examination with rectal palpation, and fecal evaluation. Fecal smears should be performed to identify Giardia and fungal elements (Histoplasma capsulatum, Pythium insidiosum), fecal flotation for parasite identification (e.g., Tritrichomonas foetus), and culture for bacteria (Campylobacter, Salmonella, Clostridium). Rectal cytology is important to exclude other causes of large-bowel diarrhea, revealing inflammatory or neoplastic cells, and certain infectious agents like H capsulatum. Additional diagnostics should include urinalysis to exclude renal causes of hypoalbuminemia or renal disease and serum T4 measurement to exclude hyperthyroidism. Serologic tests for feline leukemia virus and feline immunodeficiency virus should also be performed. Feline infectious peritonitis and toxoplasmosis should be considered as possible causes.
Chapter: Gastroenterology, Infectious Disease, Oncology
Source: The Merck Veterinary Manual, 11th Edition (Page 378)