Symptoms and Diagnosis
Acute diverticulitis typically presents with left lower quadrant abdominal pain and local tenderness accompanied by fever. In most cases, an inflammatory process is confined to the colon and its mesentery and adjacent structures or peritoneal surfaces. In the patient with diverticular perforation, a pericolic or pelvic abscess may be present with associated high fever. Patients with perforation and diffuse peritonitis usually present with severe generalized abdominal pain and associated paralytic ileus. Diffuse peritonitis may lead to septic shock with prostration and cardiovascular collapse. High-grade colonic obstruction manifests as colicky abdominal pain, bloating, and constipation or obstipation.
Abdominal findings reflect the severity and localization of the septic process. The inflamed colon or pericolic abscess causes marked localized tenderness with or without a palpable mass. In cases of diffuse peritonitis, generalized tenderness, involuntary guarding, and decreased or absent bowel sounds are noted. The presence of pneumaturia or fecaluria signifies the presence of a colovesical fistula. Severe abdominal distention suggests bowel obstruction. The diagnosis of acute diverticulitis is based on clinical findings and leukocytosis. Abdominal x-rays may show a generalized ileus and occasional pneumoperitoneum, the latter in cases of diffuse peritonitis. Marked dilatation of the more proximal colon indicates sigmoid obstruction. For patients with localized disease, computed tomography (CT) scanning has replaced barium enema as the imaging procedure of choice. However, CT scanning is usually reserved for patients with suspected abscesses or perforations, those who fail to respond to medical therapy, or in whom the diagnosis is not clear. Endoscopic evaluation is contraindicated in acute diverticulitis, as insufflation of air may cause free perforation and peritonitis. Following resolution of an acute attack, endoscopy and/or barium enema is indicated 6 to 8 weeks following hospital discharge to document the extent of colonic diverticula and to exclude colorectal carcinoma. In cases of suspected colovesical fistula, the diagnosis is usually made by urinalysis, urine culture, and cystoscopy.
Treatment
Patients with severe acute diverticulitis require hospitalization for intravenous hydration, broad-spectrum antibiotics, and bowel rest with or without nasogastric tube decompression. The initiation of medical therapy usually results in rapid clinical improvement with resolution of pain, fever, and ileus within 48 to 72 hours. Broad-spectrum antibiotics are continued for 7 to 10 days, and oral feedings are gradually reintroduced as tolerated. Following resolution of signs and symptoms, patients should consume a high-fiber diet to decrease the likelihood of repeated attacks.
Operation for diverticulitis and its complications may be either an elective or emergency procedure. Indications for elective operation include:
- Two or more acute attacks of diverticulitis successfully treated medically
- A single attack requiring hospitalization in a patient less than 40 years of age
- One attack with evidence of contained perforation, colonic obstruction, or inflammatory involvement of the urinary tract
- Inability to rule out a colonic carcinoma
Because the overwhelming majority of patients with acute diverticulitis have sigmoid colon involvement, resections of other portions of the colon are infrequent. Most patients deemed candidates for elective operation undergo a mechanical and antibiotic bowel preparation, and are treated by sigmoid colectomy with primary anastomosis. A left hemicolectomy may be required for diverticulitis of the descending colon. Isolated cecal or ascending colon diverticulitis, a rare condition usually encountered during emergency operation for presumed acute appendicitis, may require resection.
Patients who present with diffuse peritonitis or pneumoperitoneum require prompt fluid resuscitation, intravenous antibiotics, and emergency surgical exploration. Resection of the perforated colonic segment (almost always the sigmoid) with descending end colostomy and closure of the rectal stump is usually required. The former three-stage approach involved proximal colostomy and drainage, resection with colostomy, and finally colostomy closure. This method is now rarely used, as it does not consistently control the septic process. Patients with non-perforated acute diverticulitis who either deteriorate or fail to improve after 48 to 72 hours of aggressive medical therapy should undergo prompt CT scanning of the abdomen. If a macroscopic abscess is not identified, laparotomy and colon resection are performed. The identification of a large (5 cm or greater) abscess should be treated by surgical exploration with drainage of the abscess and colonic resection, or by CT-guided percutaneous catheter drainage. If the latter approach is chosen, a subsequent elective colon resection with primary anastomosis is performed after resolution of the abscess.
Patients whose acute diverticulitis is complicated by colovesical or other fistula rarely require emergent operation. Such patients are best treated medically with subsequent elective fistula takedown, colon resection, and primary anastomosis. When colonic obstruction attends diverticulitis, it is usually incomplete and allows a gentle mechanical and antibiotic bowel preparation, as well as non-emergent colon resection with primary anastomosis.
Nearly all types of elective surgery for diverticular disease are now successfully performed using laparoscopic techniques. If significant adhesions, inflammation, bleeding, or other adversity is encountered during laparoscopic surgery, conversion to an open procedure may be indicated. Such conversion is not a complication and is appropriate to ensure safe completion of the operation.
Qualifications for Performing Surgery for Diverticulitis
The qualifications of a surgeon to perform any operative procedure should be based on training (education), experience, and outcomes. At a minimum, surgeons who are certified or eligible for certification by the American Board of Surgery, the Royal College of Physicians and Surgeons of Canada, or their equivalent should perform emergency as well as elective colectomy. It is highly desirable that the surgeons performing laparoscopic colonic surgery have undergone specific advanced training in this area.
