Blood in the feces is a common finding in many conditions which range in severity from mild to life-threatening.
Blood in the feces falls into two major categories: hematochezia and melena. These categories broadly refer to the appearance of blood found in the feces, and indicate what location in the gastrointestinal tract the blood came from.
Melena is black and tarry blood in the stool that results when bleeding occurs high in the digestive tract, such as in the esophagus, stomach, or small intestine. Blood mixes with intestinal contents, and becomes partially digested.
Hematochezia refers to red, undigested blood in the stool that results from bleeding in the lower portions of the gastrointestinal tract, such as the colon, rectum, or anus.
Both melena and hematochezia have many possible causes, ranging from mild to potentially life-threatening. On its own, blood in the feces is not an indication of the severity of the underlying problem.
Bleeding in the gastrointestinal tract is either related to conditions within the digestive system itself, or a clotting disorder affecting the entire body.
Blood in the feces is a nonspecific finding that indicates a range of underlying conditions. Some associated conditions are mild, with a good prognosis, while others may be life-threatening.
Many healthy cats occasionally pass feces with small drops or streaks of blood and no other symptoms. Minor, temporary bleeding from the colon or rectum commonly occurs along with straining, stress, or the passage of particularly dry or scratchy stool.
Frequent or persistent passage of bloody stools is indicative of a variety of more serious underlying conditions and warrants veterinary attention.
Bleeding disorders, such as what occurs with anticoagulant rodenticide toxicosis, are an occasional cause of bloody stool and have the potential to be life-threatening. Cats with pale gums, extreme lethargy, and difficulty breathing require immediate veterinary attention.
Diagnostic tests often include:
Specific treatment depends on the diagnosis. Supportive care for patients with blood in the feces includes:
Some medications cause dark feces, which resembles melena. These medications include bismuth subsalicylate, sucralfate, and activated charcoal.
Many cats with hematochezia also have dyschezia (painful or difficult defecation). Distinguishing between dyschezia and painful defecation is particularly difficult in cats, as it is uncommon to observe them using the litter box.
Note: symptoms of clotting disorder indicate serious, life-threatening disease, and require immediate veterinary attention.