TL;DR: Bright red blood in your dog's stool, known as hematochezia, indicates lower gastrointestinal bleeding and requires prompt veterinary evaluation. To assist in triage, seek emergency care if other symptoms are present and take a photo of the stool for your veterinarian.
What is hematochezia and why is there red blood in my dog's stool?
Seeing bright red blood streaks in your dog's diarrhea is a condition known as hematochezia. This typically indicates bleeding in the lower gastrointestinal tract, specifically the colon or rectum. It is often caused by inflammation, which can result from dietary indiscretion, parasites, or infections. While it is a common symptom, it is never considered normal and requires professional evaluation.
How urgent is it if I see red blood in my dog's stool?
- Treat any blood in the stool as a high-priority concern requiring professional evaluation.
- Seek emergency veterinary care immediately if your dog is also vomiting, acting lethargic, has pale gums, or is refusing food.
- Be aware that while a single small streak may be mild colitis, blood can also signal life-threatening conditions like Hemorrhagic Gastroenteritis (HGE) or parvovirus.
Why should I take a photo of my dog's bloody stool for the vet?
- A clear photo allows the veterinary team to assess the volume of blood and the specific shade of red, which indicates the location of the bleed.
- Visual evidence of stool consistency helps the vet determine how quickly your dog needs to be seen.
- Providing a photo helps the medical team decide which diagnostic tests are most urgent for your pet's condition.
Clinical Context (Merck Veterinary Manual)
The acute onset of profuse hemorrhagic diarrhea, often described as resembling raspberry jam, is characteristic of hemorrhagic gastroenteritis (HGE), particularly in small or toy breed dogs. Vomiting, anorexia, lethargy, and abdominal pain are common and may precede the onset of bloody diarrhea. Rapid fluid loss can lead to hypovolemic shock before dehydration is clinically apparent. Diagnostic findings typically include hemoconcentration (PCV >55%) with normal to slightly decreased total plasma protein. Selective fecal cultures for pathogens such as Clostridium spp, Salmonella spp, and Campylobacter spp, and ELISA testing for Clostridium spp enterotoxin should be considered. While abnormalities on CBC are usually limited to hemoconcentration and neutrophilic leukocytosis, neutropenia may raise concerns for sepsis or parvovirus. In severe cases, hypovolemic and endotoxic shock manifest as poor capillary refill time, purplish mucous membranes, and cold extremities, potentially leading to death within hours.
Chapter: Gastroenterology
Source: The Merck Veterinary Manual, 11th Edition (Page 396)