Diverticulitis (summary)

Radiopaedia • CC-by-nc-sa 3.0 • de
This is a basic article for medical students and other non-radiologists

Diverticulitis is one of the presentations of diverticular disease and is most often a complication of colonic diverticulosis. Differentiating one from the other is critical since uncomplicated diverticulosis is mostly asymptomatic and acute diverticulitis is a potentially life-threatening illness.

Reference article

This is a summary article; read more in our article on diverticulitis.

Summary

  • epidemiology
    • complication of diverticulosis (so shares demographics)
    • 4% of those with diverticulosis go on to develop diverticulitis
    • elderly patients most at risk
  • presentation
    • left iliac fossa pain
    • unremitting pain with associated tenderness
    • possibly, an ill-defined mass (inflammatory phlegmon)
    • as the disease progresses, symptoms become more generalized
  • pathophysiology
    • a diverticulum is an outpouching of colonic mucosa
    • diverticula become obstructed and infected
    • initially, this is localized
    • as the disease progresses, abscess formation and peritonitis occur
  • investigation
    • CT is the modality of choice for diagnosis and assessment
    • may be diagnosed at sigmoidoscopy
  • treatment
    • depends on the severity of the illness
      • IV antibiotics and fluids to surgical treatments

Role of imaging

  • confirmation of diverticula
  • confirmation of active inflammation around diverticula
  • assess for complications, e.g. perforation, abscess
  • look specifically for fistula, e.g. with bladder
  • identify other potential causes of symptoms

Radiographic features

CT

Uncomplicated diverticulitis

  • focal fat stranding adjacent to a colonic diverticulum
    • often disproportionate to the bowel wall thickening
  • segmental thickening of the bowel wall
  • a small amount of extraluminal fluid

Complicated diverticulitis

  • diverticular perforation
    • air and fluid into the pelvis and peritoneal cavity
  • abscess formation (seen in up to 30% of cases)
    • may contain fluid, gas or both
  • fistula formation
    • gas in the bladder
    • direct visualization of a fistulous tract