TL;DR: Blood and mucus in your dog's stool indicate inflammation of the lower gastrointestinal tract and require prompt veterinary attention. Seek emergency care immediately if your dog is lethargic, vomiting, or if the stool resembles raspberry jam.
What causes mucus and blood in my dog's diarrhea?
Finding mucus and blood in your dog's stool is a sign of inflammation in the lower gastrointestinal tract, specifically the colon. Mucus is normally produced by the intestines to help stool pass, but excessive amounts indicate irritation. Bright red blood, known as hematochezia, typically suggests that the bleeding is occurring in the large intestine or rectum. This can be caused by anything from dietary indiscretion and parasites to more severe infections or inflammatory diseases.
When is blood and mucus in my dog's diarrhea considered an emergency?
- Your dog is lethargic, vomiting, has pale gums, or appears to be in pain.
- The stool looks like raspberry jam or is dark and tarry.
- The patient is a puppy, which increases the risk of serious conditions like Parvovirus.
- There is a risk of life-threatening dehydration or Hemorrhagic Gastroenteritis (HGE).
How does providing a photo of the stool help my veterinarian?
- It allows the clinical team to accurately assess the volume of blood and consistency of the mucus.
- The overall color provides vital clues about where the gastrointestinal irritation is occurring.
- It helps the vet determine how quickly your pet needs to be seen for triage.
- It allows the team to prioritize which diagnostic tests should be performed upon your arrival.
Clinical Context (Merck Veterinary Manual)
In dogs, the presence of mucus and blood in feces can help differentiate between small and large intestinal diarrhea. Large intestinal diarrhea is often characterized by very frequent defecation, decreased fecal volume, urgency, tenesmus, and the frequent presence of mucus and fresh (red) blood in the feces. While mucus is usually absent in small intestinal diarrhea, melena (dark black blood) may be present. Certain conditions, such as enteropathogenic E. coli infections, can cause extensive damage to the large intestinal mucosa, resulting in hemorrhage, edema, erosion, ulceration, and subsequent blood and mucus in the intestinal lumen. While Giardia infections are more commonly associated with steatorrhea and mucous diarrhea, blood is usually not present.
Chapter: Gastroenterology, Infectious Disease, Diagnostic Imaging, Laboratory Medicine
Source: The Merck Veterinary Manual, 11th Edition (Page 157)