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Diverticular disease

SNOMED: 397881000844 words•Updated 03/03/2026
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Exam Tips

  • Differentiate terms clearly: diverticulosis (asymptomatic diverticula), diverticular disease (symptoms without acute inflammation), diverticulitis (inflamed/infected diverticula).
  • In OSCEs, red flags requiring urgent admission are peritonism, sepsis physiology, inability to tolerate oral intake, immunosuppression, and suspected abscess/fistula/obstruction.
  • Classically, diverticular bleeding is painless and can be large-volume, unlike painful inflammatory presentations.
  • CT with contrast is the key test in suspected acute diverticulitis and to map complications; arrange lower GI evaluation after recovery when needed to exclude malignancy.
  • Use UK prescribing-safe language: state dose, duration, allergy checks, renal adjustment, and key adverse effects/contraindications (NSAIDs, fluoroquinolone cautions, metronidazole-alcohol interaction).
  • Anatomy link for viva: most diverticula are sigmoid/descending; right-sided disease is less common but relatively more frequent in people of Asian origin (see colon anatomy/diverticula distribution figures in standard GI textbooks).

Definition

Diverticular disease describes symptoms arising from colonic diverticula (most commonly sigmoid), typically intermittent left iliac fossa pain and bowel habit change without overt acute inflammation. Diverticulitis is the inflammatory/infective complication of diverticula, usually presenting with constant localized abdominal pain, systemic upset, and in severe cases perforation, abscess, fistula, obstruction, or sepsis.

Pathophysiology

Diverticula are mucosal and submucosal herniations through weak points in the colonic muscular wall where vasa recta penetrate, most often in the sigmoid colon where intraluminal pressures are highest. A low-fibre pattern may reduce stool bulk and prolong transit, increasing segmental pressure and promoting diverticulum formation; genetic susceptibility and connective-tissue/neuromuscular factors also contribute. Diverticulitis is thought to follow microperforation and localized inflammation around a diverticulum, which can progress from uncomplicated pericolic inflammation to abscess, free perforation, fistulation, stricture, and peritonitis (see standard CT-based Hinchey staging figures in core colorectal surgery texts).

Risk Factors

  • Older age (especially >50 years)
  • Family history/genetic susceptibility
  • Low dietary fibre intake
  • High red meat intake
  • Smoking
  • Obesity
  • NSAID use
  • Opioid use
  • Immunosuppression (including corticosteroid-related immune suppression)

Clinical Features

Symptoms

  • Intermittent left lower quadrant pain (may worsen after meals and improve after stool/flatus) in symptomatic diverticular disease
  • Constant, more severe lower abdominal pain in acute diverticulitis (often localizing to left iliac fossa)
  • Change in bowel habit (constipation, diarrhoea, bloating)
  • Nausea and malaise
  • Fever in diverticulitis
  • Rectal bleeding (can be abrupt and painless in diverticular haemorrhage)
  • Dysuria (particularly with adjacent inflammation or fistula)

Signs

  • Left lower quadrant tenderness
  • Localized guarding
  • Palpable abdominal or pelvic mass (possible abscess)
  • Abdominal distension or peritonism in complicated disease
  • Right-sided tenderness can occur, especially in some Asian patients with right-sided diverticula
  • Features of sepsis (tachycardia, hypotension, tachypnoea, altered mental state, reduced urine output)
  • Fistula clues: pneumaturia, faecaluria, recurrent urinary infection, faeces per vagina

Investigations

Full blood count:Neutrophilia/leukocytosis in acute diverticulitis; assess anaemia if bleeding
C-reactive protein:Raised inflammatory marker; helps gauge severity and response
Urea, electrolytes and renal function:Baseline renal status for contrast imaging, sepsis assessment, and antibiotic dosing
Urinalysis:Helps exclude urinary causes; pyuria/UTI may coexist or suggest colovesical fistula
CT abdomen/pelvis with contrast:Confirms diverticulitis and identifies complications (abscess, perforation, fistula, obstruction)
Colonoscopy or CT colonography (after acute phase if indicated):Demonstrates diverticula and helps exclude colorectal malignancy/other pathology
Faecal occult blood testing (context-specific):May support evaluation of bleeding but is not diagnostic of diverticular cause

Management

Lifestyle Modifications

  • Increase dietary fibre gradually toward about 30 g/day with adequate fluid intake
  • Encourage physical activity, weight reduction if obese, and smoking cessation
  • Review analgesic habits and avoid regular NSAID use where possible because of bleeding/perforation risk
  • Do not routinely advise avoiding nuts, seeds, or popcorn (no good evidence of benefit)

Pharmacological Treatment

Analgesia

  • Paracetamol 1 g orally every 4-6 hours when required (max 4 g/day)

First-line for pain. Avoid or minimise NSAIDs due to association with diverticular bleeding/perforation. Use opioids cautiously (constipation, ileus, and possible higher perforation risk).

Oral antibiotics for suspected uncomplicated acute diverticulitis when indicated

  • Co-amoxiclav 500/125 mg orally three times daily for 5 days
  • If penicillin allergy or co-amoxiclav unsuitable: Cefalexin 500 mg orally twice or three times daily (up to 1-1.5 g three or four times daily if severe) plus Metronidazole 400 mg orally three times daily for 5 days
  • Alternative: Trimethoprim 200 mg orally twice daily plus Metronidazole 400 mg orally three times daily for 5 days
  • Alternative (specialist advice only): Ciprofloxacin 500 mg orally twice daily plus Metronidazole 400 mg orally three times daily for 5 days

Antibiotics are not always required in clinically stable, uncomplicated disease; prescribe based on systemic illness/comorbidity/risk profile. Safety: check allergy history, renal function, drug interactions; counsel on C. difficile risk. Avoid metronidazole with alcohol (disulfiram-like reaction). Fluoroquinolones have MHRA safety restrictions (tendon, neurologic, aortic risks), so reserve for specialist-directed use.

Intravenous antibiotics for complicated or severe disease (hospital)

  • Co-amoxiclav 1.2 g IV three times daily
  • Cefuroxime 750 mg IV three or four times daily plus Metronidazole 500 mg IV three times daily
  • Amoxicillin 500 mg IV three times daily plus Gentamicin (weight/level-based once daily) plus Metronidazole 500 mg IV three times daily

Use local microbiology policy and sepsis principles. Adjust for renal impairment, pregnancy status, and allergy. Escalate urgently if peritonitis, sepsis, obstruction, or failure of conservative treatment.

Surgical / Interventional

  • Image-guided percutaneous drainage for suitable diverticular abscess
  • Urgent operative management for generalized peritonitis, free perforation, uncontrolled sepsis, or obstruction (e. g, resection with/without stoma such as Hartmann’s procedure)
  • Elective sigmoid resection may be considered for recurrent, persistent (smouldering), fistulating, or stricturing disease after specialist MDT review

Complications

  • Diverticular haemorrhage (often sudden and painless; may be massive)
  • Pericolic or pelvic abscess
  • Perforation and purulent/faecal peritonitis
  • Sepsis
  • Fistula formation (especially colovesical)
  • Stricture and large bowel obstruction
  • Recurrence and chronic smouldering inflammation

Prognosis

Most people with diverticulosis remain asymptomatic, and most episodes of uncomplicated diverticulitis settle with conservative treatment. Recovery from CT-confirmed uncomplicated episodes is commonly around 2 weeks, but recurrence is frequent (roughly one-third overall, many within 1-5 years). Complicated presentations carry substantially higher morbidity and mortality, particularly in immunocompromised patients.

Sources & References

💊BNF Drug References(14)

✅NICE Guidelines(1)

📖Textbook References(20)

  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1836)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 715, 716)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 255)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 707, 708)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 708)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 656)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1836)[context]
  • [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 642, 643)[context]
  • [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 641, 642, 643)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1188, 1189)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1189)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 991)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1190, 1191)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1188)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1188)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1189)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1187)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1184)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1191)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1188)[context]

Sources

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