Diverticulitis is a condition characterized by inflammation and infection occurring in outpouchings of the wall of the large bowel (colon), resulting in a variety of intestinal symptoms.
What is going on in the body?
Diverticula (singular, diverticulum) are small sacs or outpouchings that may form from the inside to the outside of the wall of the large bowel, most commonly, the sigmoid colon or left colon. A person's diet is thought to play a role in the formation of diverticula.
When a person is found to have diverticula, with symptoms or not, the diagnosis "diverticulosis" applies. Twenty to 25 percent of the time, the diverticula become inflamed, symptoms usually occur, and the condition is called "diverticulitis".
What are the causes and risks of the disease?
Diverticulitis can only occur in people who have diverticulosis. The condition is more frequent with increased age, occurring in one third of people older than 45 and two thirds of those older than 85.
Diverticulosis is more common in people who have a low intake of fiber and a high intake of fat - a typical "Western diet."
Diverticula usually occur in the left side of the colon, most commonly in the lower (sigmoid) portion.. This may be due to higher pressure in this part of the bowel.
Once a diverticulum has formed, it may become infected if an item in the stool (like a kernel of popcorn, for example), blocks the opening of the diverticulum. This obstruction can cause infection ,inflammation, and symptoms of diverticulitis.
What can be done to prevent the disease?
The key is to prevent the diverticulosis from developing. Eating a diet high in fiber and low in dietary fat is thought to decrease the risk of diverticulosis. Once Once a diverticulum forms, there is no way to get rid of it, but eating more fiber may prevent additional diverticuli from forming.
How is the disease diagnosed?
Diverticulitis is suspected after a history and physical examination. A history of lower, left-sided abdominal pain is a clue.
The physical exam often reveals a tender abdomen. Tightness of the abdominal muscles, called abdominal rigidity, may suggest a more serious infection.
The white blood cell count is often elevated. A test called a CT scan may be used to confirm the diagnosis.
Sometimes, the symptoms of diverticulitis mimic acute appendicitis. In this case, the diagnosis is made at surgery when the appendix is found to be normal but the left colon has signs of inflammation.
Long Term Effects
What are the long-term effects of the disease?
Most people will recover without long-term health effects. However, because diverticulosis still is present, the disease can occur again. If it happens many times, surgery may be needed to remove part of the colon.
Severe cases may also lead to other serious complications, such as:
- developing a hole in the bowel or a fistula, an abnormal connection between two sections of bowel
- abdominal infections such as peritonitis
- life-threatening blood infections known as sepsis
- obstruction of the bowel
What are the risks to others?
The disease poses no risk to others and is not inherited.
What are the treatments for the disease?
Mild cases can be treated at home with a clear liquid diet and antibiotics for about a week to 10 days. Mild implies that the patient can take fluids and antibiotics by mouth and not vomit.
In more serious cases, the person should be treated in the hospital. In this setting, the bowel is allowed to rest. This means the person should not eat or drink anything.
Fluids and antibiotics are given through an intravenous line.
Surgery may be needed if the bowel has holes, blockages, abscesses, or if heavy bleeding occurs. Some people may need part of the bowel removed surgically.
The CT scan has been used to direct needle drainage of some infections from diverticulitis, but this is usually followed later by surgery to remove the diseased bowel. More diverticular surgery is being performed with a laparoscope after the infection is controlled by antibiotics.
It is no longer clear whether a second episode of diverticulitis in the same area requires surgical removal (resection) of the involved bowel.
Patients who take immune suppressing medications (such as after a transplant) may undergo resection to prevent future infections from diverticulitis.
What are the side effects of the treatments?
Antibiotics can cause side effects, including, stomach upset, diarrhea from a bacteria called C. difficile which can be serious, and allergic reactions. Surgery can be complicated by bleeding, infection, or an allergic reaction to the anesthetic.
What happens after treatment for the disease?
Most people will recover completely. After recovery, a physician may perform a colonoscopy to look at the inside of the bowel directly, or evaluate the condition of the bowel with an abdominal CT scan. Close followup with a healthcare provider is essential.
How is the disease monitored?
Some people have repeated attacks of diverticulitis. If a classic symptom such as left-sided abdominal pain reappears, the person should see his or her healthcare provider immediately. Blood tests and CT scans may be used to monitor the diverticulosis.
Harrison's Principles of Internal Medicine, 1998, Fauci et al, pp. 1648-1649.