– Inflammation of acquired, saclike projections (diverticula) that have formed in the gastrointestinal wall and have pushed the mucosal lining through the surrounding muscle; they may become infected, bleed, or rupture.
Causes and Incidence
Diverticula are thought to be caused by an increase in intraluminal pressure in the bowel, which forms a pouch in weakened areas of the wall. The mechanism that weakens the wall is unclear. However, a highly refined diet lacking in fiber is believed to be a contributing factor. Abnormal colonic motility patterns and spastic colon have also been implicated. The formation of diverticula is known as diverticulosis. An infection of the diverticula that causes inflammation is diverticulitis.
Diverticulosis and diverticulitis are most common in developed Western countries. The incidence of diverticulosis increases with age, and approximately one third of those over 60 years of age have the disease; of those, 10% to 20% will develop diverticulitis. Diverticulitis is more severe in those under 50 years of age, and men are three times more likely than women to be affected in that age group.
Diverticulitis occurs when undigested food mixed with bacteria accumulates in a diverticulum, forming a hard mass called a fecalith. The fecalith diminishes the blood supply to the diverticulum and an infection ensues, followed by inflammation and a microperforation of the diverticular mucosa, submucosa, and adjacent serosa into the surrounding pericolic fat. A pericolic abscess forms, which may range from microscopic to a large mass. Repeated episodes of diverticulitis lead to scarring, fibrosis, and stricture of the bowel wall and continued narrowing of the lumen.
Complaints of pain and localized tenderness in the lower left abdominal quadrant with a low-grade fever are the usual presenting symptoms. Nausea, vomiting, and abdominal distention are also seen.
Intestinal obstruction, fistula formation, and perforation of the bowel with peritonitis and hemorrhage are possible complications of recurrent bouts of diverticulitis.
A history of diverticulosis, complaints of localized abdominal pain, and a possible palpable abdominal mass are highly suggestive. A water-soluble contrastenema or computed tomography scan is used to outline diverticula and display effacement of pericolic fat. Laboratory tests reveal a polymorphonuclear leukocytosis with an elevated sedimentation rate.
Bowel resection with or without colostomy to treat recurrent attacks or complications.
Analgesics for pain; antibiotics for infection; stool softeners.
NPO with bed rest, nasogastric tube and IV hydration for acute attack; high-fiber diet after inflammation resolves; instruction about continuing diet with high-fiber content; colostomy care instructions.