Diverticula are sacs formed by a fold of the lining of the intestinal wall. They extend through the muscle surrounding the bowel, and occasionally trap feces moving through the intestine may divert into them and become trapped. Diverticula are extremely common and usually harmless. They tend to appear after age 40 and are more likely to appear in seniors.
Diverticulosis is the condition of having one or more diverticula. Usually there are no symptoms or problems associated with this condition.
Occasionally, diverticula become inflamed. If you have one or more inflamed diverticula, you are diagnosed with diverticulitis. The word ending "-itis" means inflammation. Diverticulitis can be a serious condition.
Diverticula often appear in bunches. Each is typically less than an inch in diameter. Rare giant diverticula can be up to 6 inches in diameter, and always appear alone.
Diverticula can also appear in the gastrointestinal tract above the stomach, in the esophagus. In these cases, it's food rather than feces that may get trapped. Esophageal diverticula don't cause dangerous problems, but a few people find that trapped food comes back up when they bend over or lie down.
It's believed that most diverticula are caused by unnoticed muscle spasms, or by pairs of muscles that don't contract in a synchronized manner. This puts brief but intense pressure on the mucosal layer, causing pressure at the weakest points. The weakest points are the areas around blood vessels that pass through the inside of the wall of the large intestine (also called the colon). Older people have frailer tissue lining the bowel - this is probably why they have more diverticula.
Nobody is sure what causes giant diverticula. One popular theory is that a hole in the mucosal layers acts as a valve. It lets bowel gas in but not out, inflating the tissue like a balloon.
Factors which may increase your chance of developing diverticula include a low-fibre diet and lack of exercise. Being overweight can also increase the risk of developing diverticulitis.
Diverticulosis is unnoticeable if there are no complications. Most people live their whole lives without their diverticula ever becoming noticeable.
Bleeding and inflammation are two possible complications of diverticulosis.
Bleeding can result if feces get lodged in a diverticulum. The bowel draws fluid out of feces before ejecting it. If it stays there a long time, it becomes dry and hard. It can erode nearby blood vessels. Occasionally a large amount of bright red blood comes out of the rectum. If heavy bleeding continues, it's an emergency requiring immediate hospital treatment. If a very small amount leaks out continually, it can still add up over time and cause mild anemia. Bleeding that doesn't stop always requires treatment.
The other potential problem caused by diverticula is inflammation - in other words, diverticulitis. Unlike bleeding diverticula, inflamed and infected diverticula can become extremely painful. Sudden pain is particularly bad in the lower left abdomen, as most diverticula occur in the left side of the bowel. Pressing this area gently will make the discomfort worse. You may also experience nausea and vomiting, changes in bowel habits, and potential difficulty or pain while passing urine. You might also run a fever.
Diverticulitis can range from being mildly uncomfortable to dangerous. It depends on the amount of inflammation in the bowels. A fistula is a tunneling inflammation that eats its way from one organ to another. Organs near the bowel (e.g., the bladder, uterus, and vagina) can be affected. If the inflammation eats through the bowel wall or if the bowels are perforated, stool can spill into the abdominal cavity. The resulting infection and inflammation creates a serious situation known as peritonitis. Peritonitis is the name used when large parts of the abdominal cavity are inflamed. People with peritonitis always have a fever, and the belly often feels hard and bloated. Untreated, peritonitis causes death in a few hours or days.