Overview
Diverticular Disease & Diverticulitis
1. Topic Overview (Clinical Overview)
Summary
Diverticular disease encompasses a spectrum: Diverticulosis (presence of diverticula – asymptomatic), Diverticular Disease (symptomatic diverticula), and Diverticulitis (inflammation/infection of diverticula). Diverticula are outpouchings of colonic mucosa through weak points in the bowel wall (where blood vessels penetrate). They are most common in the sigmoid colon and associated with low-fibre Western diets. Diverticulitis typically presents as Left Iliac Fossa (LIF) pain + Fever. Complications include abscess, perforation (Faecal peritonitis – Surgical emergency), fistula, and stricture. The Hinchey classification grades complicated diverticulitis (I-IV). Management of uncomplicated diverticulitis is often conservative (Oral antibiotics or observation); complicated disease may require IV antibiotics, CT-guided drainage, or emergency surgery (Hartmann's Procedure). Diverticula are also a common cause of painless massive lower GI bleeding.
Key Facts
- Diverticulosis: Asymptomatic presence of diverticula. Very common (>50% of those >70).
- Diverticular Disease: Symptomatic (Pain, Bloating, Altered bowel habit) without inflammation.
- Diverticulitis: Inflammation/Infection. LIF pain + Fever + Raised Inflammatory Markers.
- Location: Sigmoid (95% in West). Right-sided more common in Asia.
- Hinchey Classification: I (Pericolic Abscess) – IV (Faecal Peritonitis).
- Complications: Abscess, Perforation, Bleeding, Fistula, Stricture.
- Treatment Uncomplicated: Conservative (Oral Antibiotics or Observation).
- Treatment Complicated: IV Antibiotics, Drainage, Hartmann's (Emergency).
Clinical Pearls
"Left-Sided Appendicitis": Diverticulitis is sometimes called this because of LIF pain and tenderness.
"Low Fibre Diet = More Diverticula": Western diets are strongly associated.
"Painless PR Bleeding from Diverticula": One of the most common causes of massive lower GI bleed.
"Perforation = Surgical Emergency": Free perforation with faecal peritonitis requires emergency surgery.
Why This Matters Clinically
Diverticular disease is extremely common. Recognising complicated diverticulitis (Peritonism, Sepsis) and escalating appropriately saves lives.
2. Epidemiology
Incidence
- Diverticulosis Prevalence: ~10% at 40 years. ~50% at 70 years. >65% at 80 years.
- Diverticulitis: ~20% of those with diverticulosis develop symptoms. ~10% develop diverticulitis.
- Sex: Slight male predominance for complications.
- Geography: West (Sigmoid). Asia (Right-sided).
Risk Factors
| Factor | Notes |
|---|---|
| Low Fibre Diet | Western diet. Strongest modifiable risk factor. |
| Age | Risk increases with age. |
| Obesity | |
| Lack of Physical Activity | |
| Red Meat Consumption | |
| Smoking | Risk of perforation. |
| NSAIDs / Steroids / Opioids | Increase risk of perforation/bleeding. |
| Constipation | Increased intraluminal pressure. |
3. Pathophysiology
Formation of Diverticula
| Step | Detail |
|---|---|
| Increased Intraluminal Pressure | Low fibre diet -> Small, hard stool -> Increased colonic segmentation pressure. |
| Weakness at Penetrating Vessels | Blood vessels penetrate muscularis. Weak points. |
| Mucosal Herniation | Mucosa and Submucosa herniate through muscle at weak points (False diverticula). |
| Diverticulum Forms | Outpouching, usually at sigmoid (High pressure). |
Diverticulitis
| Step | Detail |
|---|---|
| Faecalith Obstruction | Faecal matter obstructs diverticulum neck. |
| Microperforation | Ischaemia and Microperforation. |
| Localised Inflammation | Pericolic inflammation. |
| Complications | Abscess, Perforation, Fistula, Obstruction, Bleeding. |
4. Clinical Presentation
Diverticulosis
Diverticular Disease (Symptomatic, No Inflammation)
Acute Diverticulitis
| Feature | Notes |
|---|---|
| LIF Pain | Constant. Localised tenderness. "Left-sided appendicitis". |
| Fever | Low-grade to high. |
| Change in Bowel Habit | Diarrhoea or Constipation. |
| Nausea / Vomiting | |
| Urinary Symptoms | If colovesical fistula or bladder irritation. |
| Raised Inflammatory Markers | CRP, WCC. |
Complicated Diverticulitis
| Complication | Features |
|---|---|
| Abscess | Swinging fever. Palpable mass. Sepsis. |
| Perforation | Generalised peritonitis. Rigid abdomen. Free air on CT. |
| Fistula | Colovesical (Pneumaturia, Faecaluria, Recurrent UTI). Colovaginal (Passage of gas/faeces per vagina). |
| Stricture / Obstruction | Constipation. Abdominal distension. |
| Bleeding | Painless, Massive PR bleed. Dark red blood. |
Asymptomatic.
Common presentation.
Incidental finding on colonoscopy or CT.
Common presentation.
5. Hinchey Classification (Perforated Diverticulitis)
| Stage | Description |
|---|---|
| Ia | Pericolic Phlegmon (Confined inflammation). |
| Ib | Pericolic Abscess (Contained). |
| II | Pelvic/Distant/Retroperitoneal Abscess. |
| III | Purulent Peritonitis (General peritonitis, NO faecal contamination). |
| IV | Faecal Peritonitis (Perforation with faeces). |
Hinchey I-II: May be managed conservatively or with drainage.
Hinchey III-IV: Usually require emergency surgery.
6. Investigations
Blood Tests
| Test | Expected |
|---|---|
| FBC | Leucocytosis. |
| CRP | Elevated. |
| U&E | Baseline. Dehydration. |
| Blood Cultures | If sepsis. |
Imaging
CT Abdomen/Pelvis with Contrast (Gold Standard)
| Finding | Notes |
|---|---|
| Diverticula | Outpouchings. |
| Bowel Wall Thickening | >mm. |
| Pericolic Fat Stranding | Inflammation. |
| Abscess | Fluid collection with rim enhancement. |
| Free Air | Perforation. |
| Fistula | Air in bladder. |
CT is diagnostic and stages severity (Hinchey).
Colonoscopy
- NOT in Acute Diverticulitis (Risk of perforation).
- 6-8 Weeks After Resolution: To exclude malignancy (Similar presentation).
7. Management
Principles
- Assess Severity (Uncomplicated vs Complicated).
- Supportive Care (Hydration, Analgesia).
- Antibiotics (If bacterial infection likely).
- Drainage (CT-guided for abscesses).
- Surgery (Emergency for perforation/peritonitis).
- Follow-up Colonoscopy (Exclude Cancer).
Uncomplicated Diverticulitis
| Setting | Management |
|---|---|
| Mild (Outpatient) | May observe without antibiotics (Per recent evidence). Or Oral Co-Amoxiclav (5-7 days). Clear liquids -> Low residue diet. |
| Moderate (Inpatient) | IV fluids. IV Antibiotics (Co-Amoxiclav or Ceftriaxone + Metronidazole). NBM initially. |
Trend is towards less antibiotic use for uncomplicated cases.
Complicated Diverticulitis
Abscess (Hinchey I-II)
| Size | Management |
|---|---|
| <3-4cm | IV Antibiotics alone. |
| >cm | CT-guided Percutaneous Drainage + IV Antibiotics. |
| Failed Drainage | Surgery. |
Perforation / Peritonitis (Hinchey III-IV)
| Scenario | Management |
|---|---|
| Purulent Peritonitis (III) | Emergency Surgery. Laparoscopic lavage (Controversial) or Resection. |
| Faecal Peritonitis (IV) | Hartmann's Procedure: Resection of sigmoid + End Colostomy. (May reverse later). |
Hartmann's Procedure
- Emergency resection of diseased sigmoid.
- Formation of End Colostomy.
- Closure of rectal stump.
- Stoma reversal can be attempted after 3-6 months.
Elective Surgery
| Indication | Notes |
|---|---|
| Recurrent Diverticulitis | After 2+ episodes (Consider elective resection). |
| Complicated (Fistula, Stricture) | Elective resection + Anastomosis. |
| Immunocompromised | Lower threshold for surgery. |
Management of Diverticular Bleeding
| Intervention | Notes |
|---|---|
| Resuscitation | Transfusion, IV fluids. |
| Colonoscopy | May identify source. Endoscopic haemostasis (Clipping, Injection). |
| Angiography | If massive bleed. Embolisation. |
| Surgery | If refractory. May need segmental or subtotal colectomy. |
Most diverticular bleeding stops spontaneously.
8. Complications
| Complication | Notes |
|---|---|
| Abscess | Pericolic or Pelvic. May need drainage. |
| Perforation | Faecal/Purulent peritonitis. Surgical emergency. |
| Fistula | Colovesical (Most common), Colovaginal, Coloenteric. |
| Stricture / Obstruction | Recurrent inflammation -> Fibrosis. |
| Bleeding | Massive PR bleed. May need angiography/surgery. |
9. Prognosis & Outcomes
| Scenario | Outcome |
|---|---|
| Uncomplicated Diverticulitis | Excellent. Most recover with conservative treatment. |
| Complicated (Abscess) | Good with drainage and antibiotics. |
| Perforation (Hinchey IV) | Significant morbidity and mortality (~10-20%). |
| Recurrence | ~20-30% after first episode. |
10. Prevention & Lifestyle
| Intervention | Benefit |
|---|---|
| High-Fibre Diet | Increases stool bulk. Reduces intraluminal pressure. |
| Regular Exercise | Promotes colonic motility. |
| Maintain Healthy Weight | |
| Avoid Smoking | Reduces perforation risk. |
| Avoid NSAIDs/Steroids If Possible | Reduce complication risk. |
11. Evidence & Guidelines
Key Guidelines
| Guideline | Organisation | Notes |
|---|---|---|
| NICE NG136 | NICE | Diverticular Disease: Diagnosis and Management. |
| WSES Guidelines (2020) | World Society of Emergency Surgery | Acute Diverticulitis. |
12. Exam Scenarios
Scenario 1:
- Stem: A 60-year-old woman presents with LIF pain, fever (38.5°C), and CRP of 120. CT shows sigmoid diverticula with pericolic fat stranding but no abscess or free air. What is the diagnosis and management?
- Answer: Uncomplicated Acute Diverticulitis. IV Fluids, IV Antibiotics (Co-Amoxiclav or Ceftriaxone + Metronidazole). NBM. Analgesia.
Scenario 2:
- Stem: A CT shows a 5cm pericolic abscess complicating diverticulitis. What is the management?
- Answer: CT-Guided Percutaneous Drainage + IV Antibiotics.
Scenario 3:
- Stem: A patient presents with peritonitis and CT shows free air and faecal contamination. What surgery is indicated?
- Answer: Hartmann's Procedure (Emergency sigmoid resection + End Colostomy).
14. Triage: When to Refer
| Scenario | Urgency | Action |
|---|---|---|
| Mild Symptoms, No Red Flags | Routine | GP management. Oral antibiotics (or observation). |
| LIF Pain + Fever + Raised CRP | Urgent | Surgical admission. CT. IV Antibiotics. |
| Peritonitis / Sepsis | Emergency | Resuscitation. Urgent Surgery. |
| Massive PR Bleeding | Emergency | Resuscitation. Colonoscopy/Angiography. |
| Recurrent Episodes | Routine | Colorectal Surgery. Consider elective resection. |
15. Patient/Layperson Explanation
What is Diverticular Disease?
Diverticula are small pouches that push out through the wall of your bowel, usually in the lower part (Sigmoid colon). They are very common as we get older. If they become inflamed or infected, this is called diverticulitis.
What are the symptoms of diverticulitis?
- Pain in the lower left side of your tummy.
- Fever.
- Change in bowel habit.
- Feeling generally unwell.
How is it treated?
- Mild cases: Rest, fluids, and sometimes antibiotics.
- Serious cases: Hospital admission, IV antibiotics, and sometimes surgery.
How can I prevent it?
- Eat a high-fibre diet (fruit, vegetables, whole grains).
- Stay active.
- Drink plenty of water.
Key Counselling Points
- High-Fibre Diet: "Fibre helps prevent symptoms and new pouches forming."
- Colonoscopy After Recovery: "We need to check your bowel after 6-8 weeks to make sure there are no other problems."
- Seek Help If Symptoms Worsen: "Come back if the pain gets worse, or you develop high fever or severe bloating."
16. Quality Markers: Audit Standards
| Standard | Target |
|---|---|
| CT performed for suspected acute diverticulitis | >0% |
| Follow-up colonoscopy after recovery | >0% |
| Hartmann's procedure performed for Hinchey IV | As indicated |
| VTE prophylaxis in admitted patients | 100% |
17. Historical Context
- Painter & Burkitt (1960s-70s): Proposed the low-fibre diet hypothesis for diverticular disease after studying African populations.
- Hinchey Classification (1978): Still used to grade complicated diverticulitis.
- Modern Trend: Reduced antibiotic use for uncomplicated diverticulitis. Laparoscopic surgery.
18. References
- NICE NG136. Diverticular disease: diagnosis and management. 2019. nice.org.uk
- WSES Guidelines. Acute left colonic diverticulitis. World J Emerg Surg. 2020. PMID: 32381081
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. If you have symptoms of diverticulitis, please seek medical attention.