Diverticular Disease

Case 3. SA is a 55-year-old who presents with a 2-day history of progressively worsening left lower quadrant abdominal pain. He reports having a low-grade fever, anorexia, and blood and mucus in his stools for 1 day. He recalls a similar episode a few years ago; he saw a physician elsewhere and was given a diagnosis of diverticulitis without any diagnostic testing.

Diverticular disease is a common finding in Western countries, with a prevalence of up to 70% among individuals at 60 years of age.¹ Diverticular disease encompasses a range of historically recognized diagnoses, including diverticulosis (development of diverticula, or sac-like pouches in the colon, without inflammation), acute uncomplicated and complicated diverticulitis, and diverticular bleeding.

Uncomplicated diverticulitis involves inflammatory changes of the colon with thickening of the colon wall within diverticula.² Complicated diverticulitis involves fistula formation, perforation, abscesses, and/or obstruction.³ Diverticular bleeding can occur if thinning of the mucosa and colonic musculature leads to rupture of blood vessels. Diverticulosis is often diagnosed when patients have a screening colonoscopy, whereas uncomplicated diverticulitis, complicated diverticulitis, and diverticular bleeding are often diagnosed based on symptoms and imaging.

A host of factors are thought to contribute to the pathophysiology of diverticulosis, with a known increased risk of diverticula formation associated with genetic factors, alcohol use, smoking, red meat consumption, obesity, and diet.⁴ A diet high in fiber can help increase stool bulk and subsequently decrease pressure required during defecation, which may reduce the risk of mucosal defects leading to diverticula formation.⁵ In addition, unfavorable gut micro-biota and low-grade inflammation may be implicated in diverticula formation and subsequent symptomatic disease; however, current studies are not conclusive.⁶ Some medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants, steroids, and opioids, also increase the risk of diverticular disease.⁷ Hypertriglyceridemia, hyperuricemia, hypertension, obesity, and male sex are independent risk factors for diverticulosis.⁸

Up to 25% of patients with known diverticulosis advance to diverticulitis, although the reasons for progression are not completely understood.⁹ Diverticulitis itself involves inflammation of the diverticula and colonic wall thickening associated with abdominal pain and potential suppuration and perforation. It is thought that progression likely results from a combination of host factors, fecalith formation, and bacterial stasis.³ Consuming nuts, corn, popcorn, and seeds does not increase the risk of diverticula formation or the risk of diverticulitis.¹⁰ Risk of progression to diverticulitis is higher in patients with large, left-sided diverticula or severe diverticulosis on colonoscopy.¹¹