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Melena in Rabbits

Melena is a condition in which digested blood is found in the rabbit's fecal contents, making them appear green–black or tarry colored. Though relatively rare in pet rabbits, melena typically occurs as a result of bleeding in the upper digestive tract. It can also result from bleeding that has taken place in the oral cavity or upper respiratory tract. The affected rabbit swallows and digests this blood, which then results in the appearance of the melena.

The following conditions put rabbits at a higher risk for developing melena: unsupervised chewing, stress, and diets high in simple carbohydrates and low in fiber content.

Symptoms and Types

The following are symptoms commonly associated with melena:

• Diarrhea
• Loose stool
• Tarry or green black stools
• Fecal staining of the skin around the anus
• Anorexia, weight loss
• Teeth grinding
• Abdominal distension
• Stomach ulcers (may be more common in stressed rabbits)
• Dehydration
• Paleness of mucous tissues
• Poor haircoat or hair loss

Causes

• Gastric tumors
• Gastric ulcers – typically associated with recent stress (disease, surgery, hospitalization, environmental changes)
• Obstruction in the digestive tract - tumors, foreign object
• Metabolic disorders - liver disease, kidney disease
• Swallowing of blood - oropharyngeal, nasal, or sinus lesions (abscess, trauma, neoplasia, aspergillosis)
• Reaction to drugs such as corticosteroids, analgesics
• Bacterial infection
• Clotting disorders (i.e., lack of blood  clotting, resulting in excessive bleeding)

Diagnosis

Your veterinarian will need to differentiate this occurrence of melena from other types of diseases that can change the consistency and appearance of the stools. Several disagnostic exams will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis -- the results of which may reveal anemia, if a long-standing bleeding disease was present. A detailed examination of the consistency, appearance, and content of the feces will also need to be required.

Other diagnostic tests will include X-rays of the abdomen, which may indicate an intestinal obstruction, mass, foreign body, or fluid in the abdominal cavity. Abdominal ultrasonography may show thickening of the intestinal wall, a gastrointestinal mass, or foreign body. Surgery will be indicated if an object or obstruction appears to be present in the body.