[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Diverticular disease and diverticulitis

[Conditions](https://durgical.com/en/conditions/) · [Abdomen](https://durgical.com/en/anatomy/region/abdomen/)

# Diverticular disease and diverticulitis

Diverticulitis is inflammation of small pouches (diverticula) in the colon wall, usually in the [sigmoid colon](https://durgical.com/en/anatomy/sigmoid-colon/); it causes pain in the lower left belly.

Updated 2026-10-29

## Structures involved

Tap one to see what it is and open it in 3D.

- [Sigmoid colon](https://durgical.com/en/anatomy/sigmoid-colon/)
- [Descending colon](https://durgical.com/en/anatomy/descending-colon/)
- [Taeniae coli](https://durgical.com/en/anatomy/taeniae-coli/)
- [Mesocolon](https://durgical.com/en/anatomy/mesocolon/)
- [Peritoneum](https://durgical.com/en/anatomy/peritoneum/)
- [Urinary bladder](https://durgical.com/en/anatomy/urinary-bladder/)
- [Inferior mesenteric artery](https://durgical.com/en/anatomy/inferior-mesenteric-artery/)
- [Rectum](https://durgical.com/en/anatomy/rectum/)

## In biochemistry

- [Dietary fibre](https://durgical.com/en/biochemistry/topics/dietary-fibre/)

## In histology

- [Large intestine, appendix and anal canal](https://durgical.com/en/histology/large-intestine-appendix-and-anal-canal/)

## In the clinical exam

- [Abdominal regions and quadrants: what lies under each](https://durgical.com/en/clinical-exam/abdominal-regions-and-quadrants-what-lies-under-each/)
- [Rebound tenderness (Blumberg sign)](https://durgical.com/en/clinical-exam/rebound-tenderness/)
- [Acute abdomen and peritoneal irritation](https://durgical.com/en/clinical-exam/acute-abdomen-and-peritoneal-irritation/)

## Why it happens

- [Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer](https://durgical.com/en/general-pathology/patterns-of-acute-inflammation-serous-fibrinous-purulent-abscess-ulcer/)
- [Diet, cancer and systemic disease](https://durgical.com/en/general-pathology/diet-cancer-and-systemic-disease/)
- [Small bowel and colon motility](https://durgical.com/en/physiology/small-bowel-and-colon-motility/)
- [The GI tract wall: mucosa, submucosa, muscularis, serosa; enteric plexuses](https://durgical.com/en/histology/the-gi-tract-wall-mucosa-submucosa-muscularis-serosa-enteric-plexuses/)

## What it is

Diverticula are small outpouchings of the colon wall (diverticulosis); diverticulitis is their inflammation or infection, typically in the sigmoid colon, causing left lower quadrant pain.

## Who gets it

Diverticulosis becomes more common with age and is frequent in older adults; most people never have symptoms. In Western populations disease is mainly left-sided (sigmoid), whereas right-sided diverticula are more common in Asian populations. Diverticulitis is increasingly seen in younger adults.

## Causes

- Herniation of mucosa and submucosa through weak points where the vasa recta penetrate the muscle wall (false diverticula)
- Raised intraluminal pressure and altered colonic motility
- Diverticulitis: microperforation of a diverticulum with local inflammation

## Risk factors

- Older age
- Low-fibre, high red meat diet
- Obesity and physical inactivity
- Smoking
- NSAIDs, opioids and corticosteroids (risk of perforation)
- Connective tissue disorders and immunosuppression (complicated disease)

## Pathophysiology

High segmental pressure in the sigmoid, the narrowest part of the colon, pushes mucosa out through gaps beside the vessels, between the [taeniae coli](https://durgical.com/en/anatomy/taeniae-coli/). Obstruction or erosion of a diverticulum leads to microperforation and pericolic inflammation, which can progress to phlegmon, abscess, free perforation, fistula or stricture.

## Classification

- Diverticulosis, symptomatic diverticular disease, diverticular bleeding, diverticulitis
- Uncomplicated vs complicated diverticulitis (abscess, perforation, fistula, obstruction)
- Hinchey classification of perforated disease: I pericolic abscess, II pelvic or distant abscess, III purulent peritonitis, IV faecal peritonitis
- CT-based modified Hinchey or other systems

## Symptoms and signs

- Left lower quadrant pain and tenderness, often lasting several days
- Fever and malaise
- Change in bowel habit: constipation or diarrhoea
- Nausea; urinary symptoms if inflammation is next to the bladder
- Palpable tender mass in the left lower abdomen
- Diverticular bleeding: sudden painless rectal bleeding, often without diverticulitis

## Red flags

- Generalised peritonitis: rigidity, rebound tenderness
- Sepsis: hypotension, tachycardia, high fever
- Air or faeces in the urine (colovesical fistula)
- Signs of bowel obstruction
- Failure to improve with treatment, immunosuppression
- Massive rectal bleeding

## Diagnosis

**Clinical**
Left lower quadrant pain, tenderness and fever, especially with previous episodes. Examination for peritonitis and a mass; assessment of severity and comorbidities.

**Tests**
Blood count (leucocytosis), CRP, electrolytes, [kidney](https://durgical.com/en/anatomy/kidney/) function, lactate if severe; urinalysis; pregnancy test in women of childbearing age.

**Imaging**
CT of the [abdomen](https://durgical.com/en/anatomy/region/abdomen/) and [pelvis](https://durgical.com/en/anatomy/region/pelvis/) with intravenous contrast confirms the diagnosis, grades severity and shows abscess or free air. Ultrasound is an alternative in some centres. Colonoscopy after recovery (often 6-8 weeks), particularly after complicated disease or if not done recently, to exclude cancer; it is avoided during the acute attack.

## Differential diagnosis

- Colorectal cancer (perforated or obstructing)
- Acute appendicitis (including a left-sided [appendix](https://durgical.com/en/anatomy/vermiform-appendix/) or caecal diverticulitis)
- Inflammatory bowel disease, infectious or ischaemic colitis
- Irritable bowel syndrome
- Gynaecological causes: ovarian torsion, ectopic pregnancy, tubo-ovarian abscess
- Kidney stones, pyelonephritis

## Goal of treatment

Settle the inflammation and infection, drain or remove complicated disease, avoid unnecessary surgery and antibiotics, and exclude an underlying cancer.

## Treatment

**Conservative**
Uncomplicated diverticulitis in selected immunocompetent patients: outpatient care with analgesia and clear fluids then diet as tolerated; antibiotics can be avoided in many cases (guidelines vary).

**Medical**
Antibiotics covering gram-negative and anaerobic bacteria (oral or intravenous) for complicated disease, immunosuppression, sepsis or significant comorbidity; admission when oral intake fails or pain is severe.

**Procedure**
Image-guided percutaneous drainage of larger abscesses, combined with antibiotics; small abscesses often respond to antibiotics alone.

**Surgical**
Emergency surgery for purulent or faecal peritonitis (Hinchey III-IV) or failure of other measures: Hartmann procedure, or resection with primary anastomosis with or without a diverting ileostomy.

**Surgical**
Elective sigmoid resection (often laparoscopic) is individualised: after complicated disease, for fistula or stricture, or with frequent recurrences affecting quality of life.

**Follow-up**
Colonoscopy after recovery to exclude colorectal cancer, and follow-up for recurrence.

## Drugs for this condition

- [Cefoxitin](https://durgical.com/en/pharmacology/cefoxitin/)

## Complications

- Abscess (pericolic or pelvic)
- Perforation with purulent or faecal peritonitis
- Fistula, most often colovesical (pneumaturia, faecaluria) or colovaginal
- Stricture and large bowel obstruction
- Recurrence
- Diverticular bleeding (separate from diverticulitis)

## Prognosis

Most uncomplicated episodes resolve without surgery, and many patients never have another attack. Complicated disease and perforation with faecal peritonitis carry significant mortality, especially in older and immunosuppressed patients.

## Prevention

- High-fibre diet, physical activity and healthy weight
- Not smoking
- Avoiding regular NSAID use when possible

## Test yourself

Think of the answer, then tap the question to see it.

## Where in the colon does diverticulitis most often occur in Western populations?

The sigmoid colon, causing left lower quadrant pain.

## What does Hinchey stage III and IV diverticulitis mean?

Stage III is generalised purulent peritonitis and stage IV is faecal peritonitis; both usually need emergency surgery.

## Which imaging test is preferred to diagnose and stage acute diverticulitis?

CT of the abdomen and pelvis with intravenous contrast.

## Why is colonoscopy recommended weeks after an episode of diverticulitis, and not during it?

To exclude colorectal cancer, which can mimic diverticulitis; during the acute attack it risks perforation.

## Which fistula is the most common complication of diverticulitis, and what are its signs?

A colovesical fistula, which causes pneumaturia, faecaluria and recurrent urinary infections.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/diverticular-disease-and-diverticulitis/)

## Related conditions

- [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/)
- [Acute appendicitis](https://durgical.com/en/conditions/acute-appendicitis/)
- [Large bowel obstruction](https://durgical.com/en/conditions/large-bowel-obstruction/)
- [Peritonitis](https://durgical.com/en/conditions/peritonitis/)
- [Sigmoid volvulus](https://durgical.com/en/conditions/sigmoid-volvulus/)
- [Irritable bowel syndrome](https://durgical.com/en/conditions/irritable-bowel-syndrome/)
- [Kidney stones (urolithiasis)](https://durgical.com/en/conditions/kidney-stones/)
- [Autosomal dominant polycystic kidney disease](https://durgical.com/en/conditions/autosomal-dominant-polycystic-kidney-disease/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Diverticular Disease of the Colon](https://www.ncbi.nlm.nih.gov/books/NBK541110/) (StatPearls (NCBI Bookshelf), 2026).

[← All conditions](https://durgical.com/en/conditions/)

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/conditions/diverticular-disease-and-diverticulitis/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/diverticular-disease-and-diverticulitis/