Diverticular Disease
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Direct answer
Diverticular disease covers diverticulosis, which is the presence of mucosal outpouchings through the colonic wall, and its complications. Diverticulitis is inflammation or infection of a diverticulum, and it can progress to abscess, perforation, fistula or stricture. Diverticular bleeding is a common cause of major lower gastrointestinal haemorrhage in older adults and is usually painless.
What you must remember
- False diverticula: mucosal and submucosal herniations through the muscularis propria, usually where vessels enter the wall.
- Commonest site: sigmoid colon in Western populations, while right-sided diverticula are more typical in Asian populations.
- Diverticulitis presentation: left iliac fossa pain, fever and a raised white cell count.
- Diagnosis: contrast-enhanced CT of the abdomen and pelvis confirms the diagnosis and grades complications.
- Hinchey stages: I pericolic abscess, II pelvic abscess, III purulent peritonitis, IV faecal peritonitis.
- Fistula clues: pneumaturia and faecaluria point to a colovesical fistula.
- Bleeding: often painless and self-limiting, though right-sided bleeding can be brisk and massive.
A pathway for an older patient with left-sided pain
A 62-year-old woman presents with three days of left iliac fossa pain, fever and a white cell count of 14,000 per microlitre. Her abdomen is tender over the sigmoid colon without generalised guarding.
- Confirm the diagnosis: Contrast-enhanced CT of the abdomen and pelvis confirms diverticulitis and identifies abscess, perforation or fistula.
- Grade the severity: Uncomplicated disease without abscess or perforation is managed with fluids and oral antibiotics, with admission if she cannot take oral intake.
- Treat uncomplicated disease: Antibiotics are combined with bowel rest, and the diet is advanced as pain settles.
- Drain larger abscesses: Percutaneous drainage combined with antibiotics is used for larger collections.
- Operate for perforation or failure: Peritonitis or failure of non-operative care calls for resection, sometimes as a Hartmann procedure in unstable patients.
- Review after recovery: Colonoscopy is performed once the acute phase has settled to exclude cancer, and elective resection is considered after recurrent or complicated episodes.
Where the exam tests the diverticular trap
Diverticular disease is tested through the features that tempt students toward the wrong diagnosis or the wrong timing.
- Trap: blaming painless lower bleeding on haemorrhoids alone Correct: in an older patient, diverticular bleeding is common and needs colonoscopy to find the source.
- Trap: performing colonoscopy during an acute attack Correct: acute colonoscopy risks perforation, so imaging is preferred and colonoscopy is delayed until recovery.
- Trap: choosing colectomy after every episode Correct: most episodes settle with conservative care, and surgery follows complications or recurrence.
Frequently asked questions
Which imaging test confirms acute diverticulitis?
Contrast-enhanced CT of the abdomen and pelvis confirms acute diverticulitis and grades its complications. It shows the inflamed segment, pericolic fat stranding, abscess, perforation and fistula, which together guide whether treatment is medical or surgical.
What is the Hinchey classification of diverticular peritonitis?
The Hinchey classification grades diverticular complications from stage I pericolic abscess and stage II pelvic abscess to stage III purulent peritonitis and stage IV faecal peritonitis. Higher stages carry greater risk and usually require surgical intervention.
Why does a colovesical fistula cause pneumaturia in diverticular disease?
A colovesical fistula connects the sigmoid colon to the bladder, so gas from the bowel enters urine and causes pneumaturia. Faecaluria may also occur, and this fistula is a recognised complication of diverticulitis in older patients.
How is severe bleeding from diverticulosis managed?
Severe diverticular bleeding is managed by resuscitation, colonoscopy to localise the bleed, and CT angiography if bleeding persists. Angiographic embolisation or segmental resection is used when bleeding is massive or recurrent.