Blind loop syndrome occurs when part of the small intestine becomes bypassed. The "blind loop" formed by the bypassed intestine means food can't move normally through the digestive tract. The slowly moving food and waste products become a breeding ground for bacteria, which can lead to a condition called bacterial overgrowth. As a result, nutrients may not be fully absorbed. Blind loop syndrome often causes diarrhea and may cause weight loss and malnutrition.
Blind loop syndrome — sometimes called stasis syndrome or stagnant loop syndrome — often occurs as a complication of stomach (abdominal) surgery. But blind loop syndrome can also result from structural problems and some diseases. Sometimes surgery is needed to correct the problem, but antibiotics are the most common treatment.