Sunday, January 8, 2012

Colonic Diverticular Disease

Colonic diverticulosis is among the most common diseases in developed Western countries. In the United States, diverticulosis occurs in approximately one third of the population older than age 45 and in up to two thirds of the population older than 85 years,1,2 and it also affects a significant proportion of younger adults.

Definition and causes

A diverticulum is a saclike protrusion in the colonic wall that develops as a result of herniation of the mucosa and submucosa through points of weakness in the muscular wall of the colon. The colonic diverticulum is a false or pulsion diverticulum-that is, it does not contain all layers of the colonic wall. Diverticulosis indicates the presence of multiple diverticula and generally implies an absence of symptoms (Fig. 1). Diverticular disease implies any clinical state caused by diverticula, including hemorrhage, inflammation, or their complications. Diverticulitis describes the presence of an inflammatory process associated with diverticula. Its pathogenesis is attributed to genetic and environmental factors (Box 1).
Genetic factors
Environmental factors
  • Low-fiber diet
  • Obesity
  • Decreased physical activity
  • Corticosteroids
  • NSAIDs
  • Alcohol
  • Caffeine intake
  • Cigarette smoking
  • Polycystic kidney disease
Epidemiologic factors
  • Age
  • Geography
  • Life style
  •  Ethnicity


Medical Treatment

Complicated diverticulitis refers to acute diverticulitis accompanied by abscess, fistula, obstruction, or free
intra-abdominal perforation. In the absence of complications and systemic signs and symptoms, patients with mild abdominal tenderness may be treated conservatively. Conservative treatment typically includes dietary modification and oral or IV antibiotics. This has been shown to be successful in 70% to 100% of patients.37,38,40
Uncomplicated diverticulitis may be managed in the outpatient setting with dietary modification and oral antibiotics for those without fever, excessive vomiting, or marked peritonitis, as long as there is the opportunity for follow-up. If these conditions are not met or the patient fails to improve with outpatient therapy, hospital admission is required.
Antibiotic selection should be based on appropriate coverage for gram-negative rods and anaerobic bacteria.41 Conservative treatment will resolve acute diverticulitis in 85% of patients, but approximately one third will have a recurrent attack, often within a year.5,42,43
After recovery from the first episode, use of fiber prevents recurrence in more than 70% of patients.44,45 Immunosuppressed or immunocompromised patients are more likely to present with perforation and fail medical treatment.41,42,46
Approximately 15% of patients develop pericolonic or intramesenteric abscess.47,48 Abscesses smaller than 2 cm in diameter may resolve with antibiotic treatment without any further intervention, whereas larger abscesses may require percutaneous drainage. This may prevent an emergency operation and multistaged surgeries involving the creation and closure of stoma.42,48,49
After resolution of the initial acute attack, the colon should be thoroughly evaluated with colonoscopy or contrast enema radiography.

Surgical Treatment

Surgical treatment of the disease can be evaluated emergently or electively, based on the stage of the disease and clinical presentation. Emergent sigmoid colectomy is required for patients with the following:
  • Diffuse peritonitis
  • Failure of conservative treatment
  • Persistent sepsis despite percutaneous drainage
  • Very low threshold, immunosuppressed, and immunocompromised patients who are likely to fail medical treatment and present with perforation.
Intraoperative surgical options are based on the status of the patient and the severity of intra-abdominal contamination (Hinchey classification; Box 6 and Figs. 3 to 6).50 The desired surgical option is resection of the diseased segment with primary anastomosis, with or without intraoperative lavage or resection, and anastomosis with a temporary diverting ileostomy (Figs. 7 and 8). In advanced stages of peritonitis, Hartmann's procedure (sigmoid colectomy, end colostomy, and closure of the rectal stump; Fig. 9) is the preferred operation, but it has been shown that the closure operation (Hartmann's reversal) is not only technically challenging, but may be also associated with significant postoperative morbidity and mortality.51
Box 6: Hinchey Classification
Stage I: Diverticulitis with confined paracolic abscess
Stage II: Diverticulitis with distant (pelvic, retroperitoneal) abscess
Stage III: Diverticulitis with purulent peritonitis
Stage IV: Diverticulitis with fecal peritonitis

The decision for elective colectomy after recovery from acute diverticulitis should be made on a case by case basis. After the first attack, about one third of the patients will have a later, second attack. After the second attack, another one third of patients will have another attack.40,42 Factors affecting decision making for elective surgery include the following:
  • Age
  • Medical condition of the patient
  • Frequency, persistence, and severity of the attacks
  • CT-graded severity of the attack as a predictor of failure of medical treatment and possible risk of secondary complications
  • Inability to exclude carcinoma.
  • Conservative treatment of a complicated diverticulitis attack
There is no clear consensus regarding two widely debated points in management. First, the number of attacks of uncomplicated diverticulitis is not necessarily a determinant for appropriateness of surgery, because it has been shown that elective surgery after recovery from uncomplicated episodes might not decrease the likelihood of later emergency surgery or overall mortality.40,46,52-54 Second, patients younger than 50 years may have a higher cumulative risk for recurrent diverticulitis; however, whether they are at increased risk of complications or recurrent attacks remains debatable.5,28,40-42,54
There are several important points regarding surgical technique. From a technical standpoint, the resection should be carried proximally to the compliant bowel and extend distally to the upper rectum. After sigmoid colectomy, an important predictor of recurrence is a colosigmoid rather than colorectal anastomosis. The proximal margin of resection should be in an area of pliable colon without hypertrophy or inflammation. Resection of the diseased colon must be the desired goal, along with removal of the entire thickened colonic segment(s) but not necessarily all the proximal diverticula-bearing colon. Laparoscopic colectomy is appropriate in select patients and has advantages over open laparotomy, including less pain, smaller incisions, and shorter recovery. There is no increase in early and late complications55,56 and cost and outcome are comparable with those of open resection.57
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Prevention can be achieved by elimination of the factors involved in the pathogenesis of this disease (see Box 1). Increasing the proportion of fiber in the diet, along with an increase in fluid intake, will help keep more diverticula from forming and also will help keep the existing condition from worsening. Additionally, alteration of lifestyle by weight reduction and exercise can limit the contribution of other causative factors.
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Special circumstances

There are special circumstances in which the general recommendations for the diagnostic workup and treatment of diverticulitis may not apply. These are closely associated with the presence of factors such as manifestation of the disease, patient's response to the disease, and treatment.


  • The incidence of diverticular disease, particularly diverticulitis, has increased in industrialized countries.
  • Diverticular disease can be classified as symptomatic uncomplicated disease, recurrent symptomatic disease, and complicated disease.
  • Conservative or medical management is usually indicated for acute uncomplicated diverticulitis. Indications for surgery include recurrent attacks and complications of the disease.
  • Surgical treatment options have changed considerably over the years, along with the development of new diagnostic tools and surgical approaches.
  • Indications and timing for surgery of diverticular disease are determined mainly by the stage of the disease. In addition, individual patient risk factors, along with the course of the disease after conservative or operative therapy, play a significant role in decision making and treatment.