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:
- 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)
- Paleness of mucous tissues
- Poor haircoat or hair loss
- 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)
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.
Treatment will be specific to the underlying cause, but generally, rabbits with melena usually require hospitalization for about 24 hours in order to receive medications, electrolyte therapy, and fluid therapy. These are often administered directly into the abdomen. Antibiotic therapy may also be utitlized if an infection is suspected.
If, on the other hand, your veterinarian suspects there is an object lodged in the abdomen or that your rabbit is suffering from a tumor, he or she will most likely perform a laparotomy, in which an incision is made into the abdominal wall. This will also enable your veterinarian to gather a sample of the growth for a biopsy, the only method for conclusively diagnosing whether a tumor is cancerous or not.
Living and Management
It is important that your rabbit continue to eat during and following treatment. Encourage oral fluid intake by offering fresh water, wetting leafy vegetables, or flavoring water with vegetable juice, and offer a large selection of fresh, moistened greens such as cilantro, romaine lettuce, parsley, carrot tops, dandelion greens, spinach, collard greens, and good-quality grass hay. Also, offer your rabbit its usual pelleted diet, as the initial goal is to get the rabbit to eat and to maintain its weight and nutritional status.
If your rabbit refuses these foods, you will need to syringe feed a gruel mixture until it can eat again on its own. In some cases, tube feeding is more appropriate. Your veterinarian will help you to find the best feeding method for your rabbit while it recovers. Unless your veterinarian has specifically advised it, do not feed your rabbit high-carbohydrate, high-fat nutritional supplements.
In some rabbits, the addition of leafy greens may exacerbate diarrhea. If this is the situation with your rabbit, one solution is to offer a good-quality grass hay alone. However, consult with your veterinarian before making any changes to your rabbit's normal diet.