Chapter 28: Colon and Anorectal Disease
Which of the following statements regarding diverticular disease of the colon is true?
(A) According to the Law of LaPlace, the intraluminal pressure is directly proportional to the radius of the lumen.
(B) True diverticula involve all layers of the colon wall and are most commonly found in the cecum.
(C) The lifetime recurrence rate of diverticulitis after the first attack managed conservatively is 80%.
(D) Less than 1% of persons with diverticula develop diverticula-associated bleeding.
(E) In a patient undergoing sigmoid colon resection for apparent isolated sigmoid diverticulitis, the recurrence rate for diverticulitis is 5%.
(B) Only 1–2% of US adults age 30 and younger have diverticulosis, but this increases to >50% by age 50. Approximately 10–25% of US adults with diverticulosis will develop inflammation and infection associated with a diverticulum (diverticulitis). Symptoms range from mild left lower quadrant pain amenable to outpatient treatment to free perforation and peritonitis requiring emergency laparotomy.
Colonic diverticula form primarily in the sigmoid colon and descending colon. The majority of these are false diverticula, involving herniation of the mucosa and muscularis mucosa through the colonic wall between the teniae coli in areas of penetration of vasa rectum (see Fig. 28-8). True diverticula involve all layers of the colon wall, are most commonly found in the cecum, and are more common among Asians.
FIGURE 28-8. Cross-section of the colon depicting the sites where diverticula form. From Doherty GM (ed.). Current Diagnosis & Treatment: Surgery, 13th ed. New York, NY: McGraw-Hill; 2010:Fig. 30-12.
The pathophysiology of this diverticulosis is related to a lack of dietary fiber, which results in decreased colonic motility and a small stool volume, requiring high intraluminal pressure and high colonic wall tension for propulsion. According to the Law of LaPlace, the intraluminal pressure is inversely proportional to the radius of the lumen, whereas the wall tension is directly proportional to the pressure (pressure = tension/radius). The increased intraluminal pressure results in muscular hypertrophy and development of segmentation, where the colon acts like separate segments instead of functioning as a continuous tube. Segmentation results in the high intraluminal pressures being directed radially toward the colon wall.
Most patients with uncomplicated diverticulitis will recover without surgery, and 50–70% will have no further episode. However, the risk of complications increases with recurrent disease. Elective sigmoid colectomy should be considered after a second episode or complicated diverticulitis. Treatment of sigmoid diverticulitis with sigmoid colectomy is very effective, resulting in an overall lifetime recurrence rate of 20–25%.
Bullard Dunn KM, Rothenberger ...