Diverticular Disease
Diverticulosis means asymptomatic colonic diverticula, diverticular disease means symptoms without systemic inflammation, and acute diverticulitis is sudden inflammation or infection that may be uncomplicated or complicated by abscess, perforation, fistula, stricture, obstruction or sepsis; diverticular bleeding is often a separate painless presentation.
Definition
Diverticulosis is the asymptomatic presence of colonic diverticula. Diverticular disease is symptomatic diverticula with mild abdominal pain or tenderness and no systemic symptoms. Acute diverticulitis is sudden inflammation or infection associated with diverticula and is complicated when abscess, fistula, stricture, obstruction, perforation or sepsis is present.
First principles
Terminology is clinical, not interchangeable
NICE defines diverticulosis as diverticula without symptoms, diverticular disease as symptomatic diverticula with mild abdominal pain or tenderness and no systemic symptoms, and acute diverticulitis as sudden inflammation or infection associated with diverticula. Complicated acute diverticulitis includes abscess, fistula, stricture, perforation, obstruction or sepsis. Using the correct label matters because antibiotics are not routine for uncomplicated diverticular disease (see BNF), and urgent imaging is reserved for the appropriate acute pathway.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.

