Diagnosis of Diverticulitis

Imaging tests are used to diagnosis and evaluate diverticulitis. The old fashioned x-ray of the abdomen (KUB) tells the physician very little about this disease. The barium enema is a much better imaging study. Often, the radiologist uses a different form of contrast for this test because it is best that barium does not enter the peritoneal cavity or the blood vessels. Due to the risk for a potential leak from a segment of diverticulitis into the peritoneum, radiologists often use gastrografin, hypaque, or a water soluble dye that can still be excreted by the kidneys.

Using contrast helps expose rectosigmoid diverticuli and spasm, but it is the development of small tracts of contrast (sinus tracts), that help make the diagnosis of diverticulitis. With the barium enema, the radiologist can see the tics, the spasm (often related to the patient's pain), inflamed lining, and sinus tracts. However, abscesses and how they may relate to other parts of the bowel, are not visible. For that, a CT scan is needed. In the last several years, CT scan has become rhe test of choice for diverticulitis.

There is quite a bit of controversy with CT scan regarding the use of contrast agents. Some radiologists use intravenous, oral, or rectal contrast agents and others favor giving no contrast agents at all, preferring the CT KUB.

In patient's with no large bowel disease, the rectosigmoid is seen as a clean tube in the lower pelvis leading to the rectum. If there is contrast in the lumen, the sigmoid appears as a clean, thin-walled tube surrounded by fat that appears black on CT images. The radiologists can often see the diverticuli themselves. If there is diverticulitis in addition to tics, imaging will show a narrowed tube with thick irregular walls and smudging of the fat that surrounds the infection. Sometimes, the radiologist will find that the inflammation has spread to include adjacent loops of small bowel and small or moderate-sized collections of inflammatory debris (pus) known as diverticular abscesses.

Occasionally, it can be difficult to distinguish between diverticulitis and colon cancer using contrast enema and CT scan. Making this distinction more difficult is the fact that the two conditions can occur together, such as in patients who have undetected cancer of the rectosigmoid that has perforated and become inflamed or in patients who develop cancer in a section of the large bowel that is prone to chronic diverticulitis. There are subtle CT and x-ray signs that are helpful in distinguishing the two, but a biopsy is necessary to make a definitive diagnosis.

Treatment for Diverticulitis

Diverticulosis usually requires no specific treatment, other than common sense alterations to the diet. Medications to relax the bowel also may help.

Mild cases of diverticulitis may be treated with antibiotics and supportive measures, such as a bland diet and bed rest. More severe diverticulitis may require that the involved segment be removed surgically. In uncomplicated cases, the segment is removed and the remaining segments of the rectum and descending colon are connected together. These patients may experience fecal urgency from time to time.

If the disease is more advanced and there are abscesses and involvement of adjacent small bowel loops, two-stage surgery may be necessary. First, the rectosigmoid is taken out of the loop, so that it no longer comes in contact with waste material and is given an opportunity to quiet down. To do this, a temporary colostomy prevents excreted solid materials from coming into contact with the very inflamed rectosigmoid. In the meantime, any abscesses may be drained surgically or through the skin using interventional radiology. Second, the temporary colostomy is reversed.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 30 Apr 2000

Last Modified: 14 Sep 2015