Diverticulosis is an intestinal condition characterized by the presence of small, abnormal sacs, or diverticula, in the wall of the colon. The sacs occur most frequently in the section of the large intestine just above the rectum called the sigmoid colon. There may be only a single sac (diverticulum) or there may be hundreds.

Diverticula occur when pressure in the colon pushes the inner layer of the intestinal wall through weak spots in the middle muscular layer and then pushes both the inner and outer layers outward to form pouches. Constipation appears to be a major cause of intestinal pressure.

Most patients with diverticulosis have no symptoms. When they do occur, symptoms include muscle spasms, mild pain, bloating, constipation and sometimes the appearance of blood in the stool. Patients with diverticulosis do not experience fever or other indications of infection.

When the sacs become infected, diverticulitis develops. Both diverticulosis and diverticulitis together are often referred to as diverticular disease. Diverticulosis becomes increasingly more likely to develop as a patient gets older.

Since most people with diverticulosis have no symptoms, the condition is usually detected during an imaging test for another gastrointestinal condition. When a patient is experiencing symptoms that suggest diverticulosis, a primary physician or gastroenterologist will normally collect a medical history, perform a physical examination and order blood tests and imaging tests. Imaging tests that may be used include barium enema, colonoscopy and sigmoidoscopy.