Diverticular Disease and Diverticulitis

Pouch, bleed, or inflammation

Diverticula are anatomy; symptoms define the disease state.

Colonic diverticula are usually false diverticula: mucosa and submucosa herniate through the muscular wall at weak points where vasa recta penetrate.

Diverticulosis means diverticula are present. Diverticular bleeding classically causes sudden painless hematochezia when an adjacent vasa recta ruptures.

Diverticulitis is inflammation centered on a diverticulum, usually causing focal pain, tenderness, fever, and inflammatory change in surrounding fat.

Pain points to inflammation; brisk painless blood points to the vessel.

Name the complication from the clue

Complications often announce themselves after the acute pain changes.

An abscess produces a rim-enhancing fluid collection; persistent fever despite therapy should raise suspicion for undrained infection.

A colovesical fistula produces pneumaturia, fecaluria, or recurrent polymicrobial urinary infection; a stricture produces progressive obstructive symptoms.

Free perforation with diffuse peritonitis is different from tiny contained pericolic gas and demands urgent surgical assessment.

Air in urine after sigmoid inflammation is a tract until proven otherwise.

Risk rises from quiet anatomy to failed containment

Place the finding on a severity continuum before choosing the intervention.

Diverticulosis alone has no acute inflammatory burden, while uncomplicated diverticulitis remains localized.

Abscess is contained complicated disease; free perforation with systemic illness represents failure of containment and carries the greatest urgency.

Contained or uncontained is the severity hinge.

Read the CT around the diseased segment

The important image is not just the bowel wall; it is what escaped or became tethered nearby.

Uncomplicated CT findings include segmental colonic wall thickening, an inflamed diverticulum, and disproportionate pericolic fat stranding.

A contained pericolic collection is an abscess; distant free intraperitoneal air with fluid and peritonitis suggests uncontained perforation.

Loss of the fat plane with gas in the bladder suggests colovesical fistula, while upstream dilation across a narrowed segment suggests obstruction or stricture.

Classify before you treat

The first useful branch comes from CT severity and physiologic stability.

Clinical assessment alone can misclassify diverticulitis, so CT at a first presentation confirms the diagnosis, localizes disease, grades complications, and identifies alternatives.

Stable uncomplicated disease may be managed as an outpatient with analgesia, temporary diet adjustment as tolerated, safety-net instructions, and selective rather than automatic antibiotics.

Sepsis, diffuse peritonitis, free perforation, obstruction, fistula, or an abscess requiring source control shifts care toward admission, antibiotics, drainage, or surgery.

Recovery is not a reflex drug list

After the acute episode, match colon evaluation and prevention to risk.

After complicated diverticulitis, colonoscopy is recommended after inflammation resolves to exclude a missed cancer or premalignant lesion.

After uncomplicated disease, the 2026 ACG guideline reserves colonoscopy for alarm symptoms or patients not current with colorectal cancer screening, rather than requiring it after every episode.

Prevention emphasizes a high-fiber, plant-forward dietary pattern, physical activity, healthy weight, smoking cessation, moderation of alcohol, and avoiding regular NSAID use when possible; nuts, seeds, corn, and popcorn need not be routinely avoided.