Signs and symptoms of blind loop syndrome often include:

• Loss of appetite
• Abdominal pain
• Nausea
• Bloating
• An uncomfortable feeling of fullness after eating
• Diarrhea
• Unintentional weight loss

The small intestine is the longest section of your digestive tract, measuring about 20 feet (6.1 meters). The small intestine is where food mixes with digestive juices and nutrients are absorbed into your bloodstream.

Unlike your large intestine (colon), your small intestine normally has relatively few bacteria. But in blind loop syndrome, stagnant food in the bypassed small intestine becomes an ideal breeding ground for bacteria. The bacteria may produce toxins as well as block the absorption of nutrients.

The greater the length of small bowel involved in the blind loop, the greater the chance of bacterial overgrowth.

Factors that increase your risk of blind loop syndrome include:

• Gastric surgery for obesity or ulcers
• A structural defect in the small intestine
• An injury to the small intestine
• An abnormal passageway (fistula) between two segments of bowel
• Crohn's disease, intestinal lymphoma or scleroderma involving the small intestine
• History of radiation therapy to the abdomen
• Diabetes
• Diverticulosis of the small intestine

A blind loop can cause escalating problems, including:

• Poor absorption of fats. Bacteria in your small intestine break down the bile salts needed to digest fats. As a result, your body can't fully absorb the fat-soluble vitamins A, D, E and K. Incomplete absorption of fats leads to diarrhea, weight loss and vitamin deficiency disorders.
• Damage to the intestinal lining. Toxins that are released when bacteria break down stagnant food harm the mucous lining (mucosa) of the small intestine. As a result, most nutrients, including carbohydrates and proteins, are poorly absorbed, leading to serious malnourishment.
• Vitamin B-12 deficiency. Bacteria in the small intestine absorb vitamin B-12, which is essential for the normal functioning of your nervous system and the production of blood cells and DNA. A severe B-12 deficiency can lead to weakness, fatigue, tingling and numbness in your hands and feet, and, in advanced cases, to mental confusion. Damage to your central nervous system resulting from a B-12 deficiency may be irreversible.
• Brittle bones (osteoporosis). Over time, damage to your intestine from abnormal bacterial growth causes poor calcium absorption, and eventually may lead to bone diseases, such as osteoporosis.
• Kidney stones. Poor calcium absorption may also eventually result in kidney stones.