Diverticulosis refers to herniations of the mucosa and submucosa through the colon wall. Diverticulitis occurs when these herniations become infected. The majority of cases of diverticulitis occur in the sigmoid colon although the cecum and small intestine may be affected.
Diverticulosis is an asymptomatic condition which is usually an incidental finding on sigmoidoscopy,colonoscopy, or barium enema. Diverticulitis often manifests clinically as pain in the left lower quadrant, fever, malaise, anorexia, dysuria, diarrhea or constipation. When fistulization has occured patients may note pneumaturia, fecaluria, and recurrent UTI. Painless rectal bleeding (hematochezia) is a common symptom of diverticular bleeding.
CT scanning is a useful study to establish the diagnosis. A mass may be palpated in the left lower quadrant of affected patients, although this finding may also be found in patients with Crohn’s disease or malignancy. An abdominal mass in the presence of high fever should raise the suspicion of a peridiverticular abscess. The differential diagnosis should include appendicitis, ovarian cyst, ovarian torsion, endometriosis, pelvic inflammatory disease, adhesions, ectopic pregnancy, Crohn’s disease, irritable bowel syndrome, carcinoma, and ischemic colitis.
The work up should include abdominal and chest radiographs in the supine and upright positions to evaluate for free air, intestinal obstruction, and extramural air. CT scanning is the procedure of choice to establish the diagnosis. Barium enemas using water soluble contrast and low pressure may also be used to establish the diagnosis. Since there is a potential for leakage of contrast when there is the complication of perforation, this study should not be performed when there are peritoneal signs on examination.
Therapy for diverticulitis is with antibiotics. Patients with significant fever or leukocytosis may require hospitalization. Other patients may be treated on an outpatient basis. Patients should be on a clear liquid diet or on complete bowel rest. Outpatient antibiotic therapy should include either trimethoprim/sulfamethoxazole double-strength, or ciprofloxacin HCl plus metronidazole for 7 to 10 days of therapy. Inpatient therapy should include either clindamycin or metronidazole for anaerobic coverage. The list of antibiotic choices for aerobic coverage should include aminoglycosides, cephalosporins, ampicillin and sulbactam, piperacillin and tazobactam, imipenem and cilastatin, or aztreonam. When cases are complicated by abscess formation, perforation, obstruction, or fistula, or if episodes are recurrent, then either surgical intervention or CT guided drainage may be required.