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Diagnosing and Treating Diverticulitis

Lovato, Luis M. MD

doi: 10.1097/
Living with the LLSA

Author Credentials and Financial Disclosure: Dr. Lovato is an Associate Professor for the David Geffen School of Medicine at UCLA, the Director of Critical Care for the Department of Emergency Medicine at Olive View-UCLA Medical Center, the Co-Chair for the Emergency Medicine Best Practices Committee for the Los Angeles County Department of Health Services, and a faculty instructor for the National MegaLLSA Review Course.

All other faculty and staff in a position to control the content of this CME activity have disclosed that they and their spouses/life partners (if any) have no financial relationships with, or financial interests in, any commercial companies pertaining to this educational activity.





Learning Objectives: After reading this article, the physician should be better able to:

  1. Analyze epidemiological risk factors for developing diverticulitis to determine treatment and prevention.
  2. Relate the surgical management approaches for diverticulitis as strategies for therapy.
  3. Categorize the stage of diverticulitis by Hinchey Classification to formulate a treatment plan.

Article from the 2010 LLSA Reading List


Jacobs DO

N Engl J Med


This article is an evidence-based review on diverticulitis from the Clinical Practice series in the New England Journal of Medicine. It begins by clarifying several important definitions. Diverticula are narrow-necked, full-thickness outpouchings of the colonic wall thought to be related to abnormal colonic peristalsis and pressure. Diverticulosis is asymptomatic and diagnosed when uninflamed diverticula are confirmed by radiographic imaging, endoscopy, or direct visualization. Diverticulitis is the acute symptomatic condition resulting from the luminal obstruction of preexisting diverticula by fecal material. Subsequent bacterial overgrowth, inflammation, edema, ischemia, and ultimately perforation and sepsis can occur. Complicated diverticulitis implies the existence of an abscess, fistula, obstruction, or peritonitis.

The article also highlights various epidemiological characteristics of diverticular disease, including its relative high incidence in industrialized nations, probably the result of low dietary fiber intake and lifestyle factors such as physical inactivity, obesity, and smoking. Although any portion of the colon can be affected, diverticulitis affects the sigmoid and descending colon more than 90 percent of the time. (J Clin Gastroenterol 1999;29[3]:241.) Diverticulitis usually manifests in the elderly, with 80 percent of cases occurring after age 50. (Surgery 1994;115[5]: 546.) Hinchey Classification (see table) is used to stage diverticulitis, with morbidity and the likelihood of needing surgical intervention increasing with each stage.

The article reviews these methods for classifying disease, and helps clinicians expertly diagnose the condition while ruling out other serious etiologies of left lower quadrant pain, and after reading it, physicians should understand how to use sound clinical reasoning and appropriate diagnostic testing to diagnose diverticulitis, not merely order countless laboratory panels and imaging studies.

With early stage diverticulitis, patients may present only with complaints of left lower quadrant pain and constipation. Localized left lower quadrant tenderness is generally the rule with or without fullness on exam. The differential diagnosis includes other colonic entities such as infectious colitis, inflammatory bowel disease, appendicitis, or even complications of colon cancer. Genitourinary (cystitis, nephrolithiasis, pyelonephritis), obstetric (ectopic), and gynecological (cyst, torsion, pelvic inflammatory disease) causes must also be excluded. Advanced stage diverticulitis with perforation may include peritoneal signs and sepsis. Patients who are immunocompromised (diabetes, human immunodeficiency virus, immunosuppressive therapy) often present with more complicated disease, may be more difficult to diagnose, and are less likely to respond to conservative therapy.

Computerized tomography is the diagnostic study of choice in the acute setting. Endoscopic imaging to rule out other entities such as inflammatory bowel disease or malignancy is usually delayed until the acute inflammation resolves to minimize the risk of perforation.

Patients with early uncomplicated disease and minimal comorbidities are usually candidates for outpatient therapy. Broad spectrum oral antibiotics should target bowel flora, especially gram-negative organisms and anaerobes. Patients with unrelenting nausea or pain, complicated disease, peritoneal signs, or other comorbidities, should be hospitalized, placed on bowel rest, and given intravenous antibiotics. Earlier stage disease can often be medically managed even when hospitalization is necessary. CT-guided percutaneous drainage may be required for select patients with large focal areas of phlegmon or abscess or if not responding to more conservative therapy. Even when not definitive, interventional drainage can often resolve acute disease enough so that surgery can be done electively as an outpatient rather than emergently. Same-admission surgical therapy is reserved only for advanced stage diverticulitis, and is required in less than 10 percent of admitted patients with diverticulitis. (J Clin Gastroenterol 1999;29[3]:241.) Indications for same-admission surgical therapy include failure to improve with medical management, continued peritonitis or sepsis, or advanced stage disease that is inaccessible to or fails percutaneous drainage.

Historically, surgical therapy for diverticulitis occurred as three separate operative stages: abscess drainage with placement of a proximal diverting colostomy, diseased colon resection and primary colonic anastomosis, and colostomy takedown. The three-stage approach is expensive and time-consuming, and comes with the inherent risks of multiple operations. Depending on these risks, many patients never have their colostomies taken down, which has long-term implications on the quality of life. Now, one- and two-stage operative approaches are the norm with retrospective data suggesting acceptable outcomes. (Am J Surg 2002;183[5]:525.) Laparoscopic colectomy is emerging as a surgical management strategy for select cases where surgeons trained in this technique are readily available. Observational data suggest laparoscopic colectomy may result in shorter hospital stays, reduced wound complications, and fewer overall complications compared with open colectomy. (Surg Clin North Am 2000;80[4]:1299.)

Comment: The optimal surgical management of acute diverticulitis is evolving. Advances in interventional management have decreased the need for emergent surgery because many diverticular abscesses can be “cooled off” successfully with percutaneous drainage. When surgery is indicated, one-stage operative approaches are becoming more common even with complicated diverticular disease. Having recurrent episodes of uncomplicated diverticulitis is not predictive of future episodes with complications. Once an episode of complicated diverticulitis has occurred, however, the American Society of Colon and Rectal Surgeons gives a Level B recommendation for elective colectomy. (Dis Colon Rectum 2006;49[7]:939.) Keep in mind that in this same statement, ASCRS emphasizes that decisions on elective colectomy should be made on a case-by-case basis. And finally, with more surgeons trained to perform endoscopic colectomy, it may be possible to avoid open surgery altogether even with complicated diverticular disease.

The article reiterates the common notion that diverticulitis in younger patients is often more severe and associated with more complications and recurrences. (Br J Surg 1992;79[2]: 117), but a subset analysis of more than 500 patients in a study by Kaiser failed to show that diverticulitis in patients under age 40 had any differences in presentation, complications, or outcomes. (Am J Gastroenterol 2005;100 [4]:910.)

This article supports the widespread practice of using CT as the initial radiologic examination of choice for diverticulitis. Indeed, evidence shows that CT is highly sensitive (97%) and very specific for diagnosing diverticulitis. (Br J Surg 1997;84[4]:532.) What the article does not mention is that CT is not always necessary. In the article by Kaiser looking specifically at the role of CT for diverticulitis, 19 percent of patients were diagnosed solely on clinical grounds (Stage 0 diverticulitis), and managed successfully without imaging. Opting not to scan a patient with mild diverticulitis may seem novel when knee-jerk CTs are vogue, but it is a strategy supported by some evidence. (Am J Gastroenterol 2005;100 [4]:910.)

The exceptional emergency physician gets the diagnosis right, ruling out other serious etiologies of left lower quadrant pain, not by ordering countless laboratory panels and imaging studies, but by using sound clinical reasoning and appropriate diagnostic testing. He recognizes impending intra-abdominal catastrophe without delay and expertly manages the truly sick diverticulitis patient with early resuscitation, early antibiotics, and early consultation. He carries great respect for the ability of immunocompromise to mask serious disease, especially intra-abdominal infection. And when the diagnosis is readily apparent and the condition is mild, he sends the patient home without introducing the risks of radiation or contrast exposure, with a course of antibiotics, dietary education, return precautions, and appropriate follow-up. After all, there is another patient waiting to be seen.

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