Tina Jenq, MD
Department of Surgery
Alessandro Fichera, MD
Department of Surgery
University of Chicago
Introduction: Diverticular disease is a growing health problem in the Western world, where left-sided involvement is typical. Although right-sided diverticulitis is seen regularly in Asia, it constitutes only a fraction of colonic diverticula cases in Western populations.
Results and discussion: This paper describes the case of a patient who presented to the hospital because of a sudden onset of right flank pain. Computed tomography (CT) scans of his abdomen and pelvis showed a solitary mass in the hepatic flexure. The mass was initially suspected to be perforated colon cancer and was resected during an emergency laparotomy. A histologic examination revealed true diverticula with pericolonic abscess, serositis, and perforation. The authors discuss the differences between true and false diverticula and review the literature regarding diagnosis and management of right-sided diverticula.
Conclusion: True right-sided diverticulitis often responds to conservative management with antibiotics, and recurrence is rare. CT scanning can help facilitate the diagnosis of uncomplicated diverticulitis. Typical CT findings include an inflamed right colonic diverticulum, pericolonic inflammation or abscess, and colonic wall thickening. Accurate preoperative diagnosis is difficult but could prevent unnecessary laparotomy and bowel resection in many cases.
Diverticular disease is being seen with greater frequency in the Western world and involves an increasingly younger patient population.1 The most common clinical presentation of diverticular disease in Western countries is left-sided, with extension to the right when diverticulosis of the entire colon is present. Right-sided diverticulitis constitutes only 0.9% to 1.7% of all colonic diverticula in Western populations.2,3 In Asia, right-sided diverticulitis, which primarily involves the cecum, is the rule rather than the exception. The largest reported series come from Hong Kong4 and Japan.5
Diagnosing right-sided diverticulitis is challenging, and most lesions are found at laparotomy in a predominantly cecal distribution. Our patient presented with a rare case of a perforated diverticular inflammatory mass with disease limited to the hepatic flexure.
The authors have no relationship with any commercial entity that might represent a conflict of interest with the content of this article and attest that the data meet the requirements for informed consent and for the Institutional Review Boards.
A 43-year-old African American man presented to the hospital after experiencing a sudden onset of right flank pain, which had persisted for the previous 2 days. He described it as being poorly localized, progressive, and unrelated to oral intake. He reported no nausea, vomiting, obstipation, or constipation. His temperature was 37.4°C, heart rate was 80 beats per minute, and blood pressure was 160/52 mm Hg. On physical examination, localized tenderness to palpation was elicited in the right abdomen. A rectal examination revealed guaiac-negative stool. The patient's white blood cell count was 8.2 x 109/L (normal, 3.5—11 x 109/L), and liver function tests were normal. An infused computed tomography (CT) scan of the abdomen and pelvis showed a solitary mass in the hepatic flexure, which was suggestive of perforated colon cancer (Figure 1).
The patient developed a low-grade fever, and his abdominal tenderness increased. He underwent an emergency exploratory laparotomy. We saw no evidence of purulent or feculent contamination. A large, firm mass was found in the hepatic flexure. We suspected that this mass could be perforated colon cancer, and it was resected via an oncologic right hemicolectomy. Histological examination revealed the patient's condition to be true diverticula with pericolonic abscess, serositis, and perforation (Figure 2). After surgery, the patient's fever and abdominal pain subsided. He had an uneventful hospital course and was discharged on postoperative day 8 after a short course of ceftriaxone.
|Figure 1—CT scan of the abdomen and pelvis (coronal view) showing a nonobstructing colonic mass at the level of the hepatic flexure with associated pericolonic inflammatory changes.|
|Figure 2—Histopathology images using hematoxylin and eosin staining showing true diverticula. Inflammatory cells distort the wall architecture of the submucosa, and acute serositis with purulent exudate of the outer wall can be seen (A); perforation with destruction of mucosal integrity is also observed (B).|
Right-sided colonic diverticula were first described by Potier in 1912 and account for approximately 0.9% to 1.7% of all colonic diverticula cases in Western populations.2-3,6 In the English-language literature, cases of right-sided diverticula are usually noted as pancolonic diverticulosis and not as isolated entities. Colonic diverticula ascending away from the cecum are even more unusual. A review of 188 cases of right-sided diverticula found that only 12% were proximal in the ascending colon.7 Right-sided diverticulitis is usually diagnosed in patients with an average age of 40 years, which is older than the typical age of patients who present with appendicitis and younger than those diagnosed with the more common left-sided diverticulitis.7
Etiology Diverticula are classified as true or false. True diverticula are outpouchings of all layers of the bowel wall. They are less common than false diverticula and are thought to be congenital. The classically described solitary cecal diverticulum was hypothesized to be a remnant embryonic appendage (a true diverticulum). Hughes demonstrated through postmortem histology of right-sided diverticula, however, that 59% were actually false diverticula.8 False diverticula are outpouchings of mucosa and submucosa through points of weakness in the bowel wall where the vasa recta plunge through the muscularis propria to provide nutrient support to the mucosa. These pouches are thought to develop from increased colonic intraluminal pressure associated with slow colonic transit resulting from low fiber intake.9
Graham's review of the American experience with right-sided diverticulitis found that nearly all patients present with right flank pain and abdominal tenderness.10 An inflammatory mass may be palpable. Nausea and vomiting are less common symptoms.
It is difficult to differentiate right-sided diverticulitis from other conditions based on signs and symptoms. This makes accurate preoperative diagnosis difficult. Misdiagnoses are fairly common, as demonstrated in a report from Hong Kong, where up to 80% of cases were misdiagnosed as appendicitis and resulted in laparotomy.11 Other differential diagnoses include acute cholecystitis, Meckel's diverticulum, and, as in our patient's case, colon cancer.
The increasing use of CT scanning may improve the likelihood of diagnosing uncomplicated diverticulitis preoperatively. Typical CT findings include an inflamed right colonic diverticulum, pericolonic inflammation or abscess, and colonic wall thickening. A "halo" sign of preserved colonic wall layers may allow differentiation of diverticulitis from colon cancer.12 Oudenhoven and colleagues describe nonoperative management of 44 patients who were evaluated radiographically with ultrasonography and CT scanning and received a diagnosis of early-stage diverticulitis; only 5 patients required diverticulectomy or hemicolectomy and none required a temporary stoma.13 The use of CT scanning to correlate with the Hinchey classification to grade the severity of left-sided diverticulitis may be cautiously extrapolated to grade right-sided diverticulitis.14
The treatment of right-sided diverticulitis has not been clearly defined due to few data with regard to its natural history of progression and recurrence. Graham's review of operations performed on 375 patients with cecal diverticulitis found that 2.4% received no resections and had no morbidity, mortality, or recurrence.10 With the increasing use of CT scanning to diagnose early-stage diverticulitis, there is a shift toward expectant management and treatment with antibiotics; however, operative intervention is required for evidence of diffuse contamination, clinical deterioration, or failure to improve with nonoperative treatment. Some authors advocate performing a limited diverticulectomy when a single inflamed diverticulum can be identified,15 while others advocate ileocectomy or hemicolectiomy, particularly for a phlegmon that is indistinguishable from cancer. Operative risks, such as cardiac and respiratory complications and anastomotic leak, are highest with a right hemicolectomy. In our case, the unusual location of the patient's disease and the absence of diverticula in the rest of the colon made a diagnosis of diverticulitis seem less likely.
Right-sided diverticulitis remains uncommon and difficult to diagnose. Conservative treatment with antibiotics is becoming increasingly accepted in cases where there is no perforation. Accurate preoperative diagnosis and the growing use of CT scanning are vital in preventing unnecessary laparotomy.