A 70-year-old woman presented to the emergency room with a 3-day history of left lower quadrant pain, bloating, diarrhea, and nausea. Physical examination revealed a temperature of 38.0°C and laboratory evaluation showed leukocytosis. Computed tomography scan demonstrated diverticulosis of the sigmoid colon with associated bowel wall thickening and fat stranding but no pericolic fluid. The patient was admitted and made “nothing by mouth” (NPO) with intravenous fluid hydration. Metronidazole and ceftriaxone were started. After 2 days, the patient’s abdominal pain and diarrhea had resolved. The patient was given clear liquids initially and diet was advanced as tolerated. Six weeks after discharge to home, the patient underwent colonoscopy and was found to have extensive diverticulosis involving the descending and sigmoid colon but no evidence of malignancy. This was her second hospitalization for diverticulitis, and at surgical consultation sigmoid resection was recommended.
Therapy for acute diverticulitis depends on the presentation of the disease: complicated versus uncomplicated. In the uncomplicated setting, there is a localized infection that requires bowel rest and antibiotics. In mild cases this may be safely achieved as an outpatient with oral antibiotics.
Those patients requiring intravenous fluid resuscitation, with high fever or leukocytosis, or significant co-morbidities should be treated in the hospital setting. Elderly, immunosuppressed, and diabetic patients for example should undergo treatment as inpatients. Outpatients are restricted to clear liquids and started on an antibiotic regimen of ciprofloxacin and metronidazole. Amoxicillin-clavulanate and clindamycin may be used as alternatives. If signs and symptoms improve after 2 to 3 days, diet is advanced. These patients must receive explicit instruction to seek immediate medical attention if experiencing increase in fever or abdominal pain, if they are unable to consume adequate fluids, or if they fail to improve within 2 to 3 days. The possibility of abscess development should be explored in all patients who deteriorate or fail to improve. Intervention may include percutaneous drainage of abscesses or laparotomy under certain indications (Table Indications for surgery in at time of presentation in acute diverticulitis).
Table Indications for surgery in at time of presentation in acute diverticulitis
|Abscess (failed percutaneous drainage)|
|Clinical deterioration or failure to improve with medical therapy|
Hospitalized patients are made NPO and given intravenous hydration. Empiric broad-spectrum intravenous antibiotics are directed at colonic anaerobic and Gram-negative flora. Metronidazole and third-generation cephalosporins, fluoroquinolones (ciprofloxacin or levo-floxacin) or short courses of aminoglycosides may be used. Single agents with appropriate colonic flora coverage include pMactamase inhibitor combination antibiotics (ampicillin-sulbactam, iperacillin-tazobactam or ticarcillin-clavulanate) or carbapenems (imipenem or meropenem). If drainage of any associated abscess is performed, antibiotic coverage is tailored once the causative organisms are identified.
As noted above, colonoscopy should be performed following successful conservative therapy for a first attack of diverticulitis. Thirty to 40% of patient will remain asymptomatic, 30 to 40% will have episodic abdominal cramps without frank diverticulitis, and 33% will proceed to a second attack of diverticulitis. It was generally believed that prognosis is worse with a second attack. This is now not current belief. Most patients run “true-to-form”, that is if they have attacks manageable as outpatients with oral antibiotics, subsequent attacks often will be of similar severity. In fact, 90% of patients who present with perforation have had no preceding attack, but have a factor that predisposes to this presentation.
Patients at increased risk of more severe attacks include young patients (less than 40 or 50 years of age) and the immunosuppressed.
Patients diagnosed with complicated diverticulitis undergo a more aggressive therapeutic regimen. In the case of peritonitis, immediate resuscitation, broad-spectrum antibiotics, and surgical exploration are performed in lieu of diagnostic studies. The mortality rate of perforated diverticulitis is 6% for purulent peritonitis and 35% for fecal peritonitis. Examples of appropriate antibiotics include the combination of ampicillin or gen-tamicin plus metronidazole, imipenem/cilastin or piperacillin-tazobactam.
Diverticular obstruction must be differentiated from carcinoma. Whenever malignancy is suspected, resection is mandatory. Obstruction due to diverticulitis is rarely complete, and, therefore, patients may undergo appropriate bowel preparation prior to surgery.
With improvement in computed tomography technology, small diverticular abscesses not amenable to drainage are found and may be treated with antibiotics. Whether these cases may be treated as uncomplicated diverticulitis is under further investigation. Abscesses larger than 3-4 cm require intervention, generally via percutaneous drainage and rarely surgery in cases of failed computed tomography-guided drain placement. Macroperforation of diverticulitis leading to diffuse peritonitis is associated with a high mortality rate and surgical intervention is mandatory.
Elective surgical intervention has typically been advised after a first attack of complicated diverticulitis (abscess, fistula, or stricture) or after two or more episodes of uncomplicated diverticulitis (Table Indications for delayed operation after confirmed diverticulitis). More recent data suggest that the limit of two episodes is not mandatory in uncomplicated diverticulitis, particularly if treated as an outpatient, and tailored advice is necessary, depending on the patient’s age, preferences, and comorbidities.
Table Indications for delayed operation after confirmed diverticulitis
|Abscess responding to percutaneous drainage|
|Fistula (colovesical, colovaginal, etc.)|
|Inability to exclude carcinoma|
In the case of emergent surgical intervention in the patient with an acute abdomen, assessment of peritoneal contamination determines the advisability of a primary anastomosis versus a two-stage procedure. In the presence of fecal or purulent peritonitis, associated medical conditions, poor nutrition, immunosuppression, or emergency situations, two-stage procedures are indicated. The Hartmann procedure is a common approach which involves resection of the diseased colon, an end-colostomy, and creation of a rectal stump. The colostomy is closed 3 months later. Other two-stage procedures include primary anastomosis after resection, and a proximal diverting stoma with stoma closure at a later time. Single-stage procedures are less widely touted and include on-table washout of the proximal colon plus primary anastomosis; and laparoscopic evaluation, washout, and placement of drains without resection. The latter in particular requires additional data but is an attractive option. Currently, reported series have been highly selective.
Elective surgery after resolution of the acute episode of diverticulitis may be performed laparoscopically, and is the approach of choice for these authors. In this instance, resection and primary anastomosis are possible as long as adequate bowel preparation is achieved pre-operatively and the bowel is well-vascularized, non-edematous and tension-free.