Treatment varies with disease severity (Figure 82-1). Uncomplicated diverticulitis is isolated to inflammation of the diverticula with or without phlegmon or small abscess confined to the bowel wall. Complicated diverticulitis includes diverticular inflammation associated with abscess, stricture, obstruction, fistula, or perforation.
Algorithm for treatment of diverticulitis. NPO = nothing by mouth.
Current treatment recommendations are provided in Table 82-2.
TABLE 82-2Antibiotics for Diverticulitis
Uncomplicated diverticulitis is treated with bowel rest (liquid diet) and oral antibiotics (Table 82-2). Dietary restriction or modification is commonly recommended, but efficacy is not clear.5 There is no advantage of IV antibiotics over oral antibiotics.5 Admission is not necessary unless there are serious comorbidities or obstacles to outpatient care. If uncomplicated diverticulitis is confirmed with CT, the success rate of ambulatory treatment is about 98%.10
There is growing interest in the treatment of uncomplicated diverticulitis without antibiotics at all, due to questions about antibiotic efficacy and antibiotic adverse effects such as allergy, nausea and vomiting, and Clostridium difficile infection.5,10, 11, 12
One recent randomized controlled study in Sweden evaluated the need for antibiotics in uncomplicated diverticulitis confirmed by CT. Of the 669 patients studied, 9 patients experienced complications: three abscesses and three perforations in the nonantibiotic group and three perforations in the antibiotic group. There were no differences in outcomes between the two groups, including symptoms at 30-day follow-up, need for emergency surgery, or median hospital stay.10 The Infectious Diseases Society of America recommends a 4-day course of treatment.13 As of this writing, there is no consensus on the omission of antibiotics.
Complicated diverticulitis generally requires admission. In addition to bowel rest and IV antibiotics, specific treatments are directed to complications. Complicated diverticulitis is often referred to by the Hinchey classification scheme8: Stage 1 is small, confined pericolic or mesenteric abscesses; stage 2 is larger abscesses, extending to the pelvis; stage 3 is perforated diverticulitis and purulent peritonitis; and stage 4 refers to free perforation with fecal contamination of the peritoneal cavity.
Abscesses and phlegmon are among the most common complications. Phlegmon is inflammation and infection of tissue without abscess. Advances in percutaneous drainage of abscesses have allowed many patients to undergo less invasive treatment. Abscesses that measure <4 cm and phlegmon (Hinchey stage 1) are often admitted for IV antibiotics and do not require percutaneous drainage. Perforation has a high mortality rate, and patients need volume resuscitation, IV antibiotics, and emergent exploratory surgery. For Hinchey stage 3, the mortality rate approaches 13% and increases to 43% for Hinchey stage 4.8,14