Clinical Notes : Gastroenterology

207. Acute Diverticulitis



The terms diverticulosis, diverticular disease, and acute diverticulitis are often used interchangeably but there is wide variation in clinical features (1)

  • Diverticulosis

    • The presence of diverticula without symptoms

  • Diverticular disease

    • The presence of diverticula with mild abdominal pain or tenderness and no systemic symptoms.

  • Acute diverticulitis

    • Sudden inflammation or infection associated with diverticula. Symptoms include constant abdominal pain, usually severe and localising in the left lower quadrant. Other features, including fever, may also be present.

  • Complicated acute diverticulitis

    • The presence of complications associated with inflamed or infected diverticula. These complications may include abscess, fistula, stricture perforation and sepsis.

  • Colitis

    • Inflammation of the bowel related to Crohn's disease, ulcerative colitis, ischaemia or microscopic colitis. Symptoms may include abdominal pain and change in bowel habits with passage of blood.



Both genetic and environmental factors are causative, especially a low dietary fibre intake, which in Western populations is deemed as the predominant contributing factor.(2)


Other predisposing factors include (3), (4), (5), (6) :

  • decreased physical activity

  • obesity

  • increased red meat consumption

  • tobacco smoking

  • excessive alcohol and caffeine intake

  • steroids, and non-steroidal anti-inflammatory drugs


Other suggested aetiologies include

  • alterations in colonic wall structure (increased type III collagen synthesis, elastin deposition)

  • abnormal colonic motility, and colonic neurotransmitter dysfunction (decreased choline acetyltransferase, increased serotonin expression).(7), (8), (9)


Connective tissue abnormalities such as Ehlers-Danlos syndrome, or herniosis, have been implicated in the concurrence of disorders referred to as Saint's triad (hiatus hernia, colonic diverticulosis, gall stones).(10), (11)


Infection of the diverticula may be the cause of inflammation that results in diverticulitis.


There is no evidence to support the theoretical concern that ingested seeds and nuts could become trapped within a diverticulum and result in an episode of diverticulitis.


Clinical features of diverticulosis, diverticular disease, and acute diverticulitis

Divert clinical.png

Symptoms and signs of complicated acute diverticulitis


Suspect complicated acute diverticulitis and refer for same-day hospital assessment if the person has uncontrolled abdominal pain and any of the symptoms and signs that suggest complicared acute diverticulitis.

diverticulitis sx.png

Investigations of suspected acute diverticulitis (1)


Primary care

  • For people with suspected uncomplicated acute diverticulitis who are not referred for same-day hospital assessment:

    • reassess in primary care if their symptoms persist or worsen and

    • consider referral to secondary care for further assessment.


Secondary care

  • For people with suspected complicated acute diverticulitis who have been referred for same-day hospital assessment, offer a full blood count, urea and electrolytes test and C‑reactive protein test.

  • If the person with suspected complicated acute diverticulitis has raised inflammatory markers, offer a contrast CT scan within 24 hours of hospital admission to confirm diagnosis and help plan management. If contrast CT is contraindicated, perform one of the following:

    • a non-contrast CT or

    • an MRI or

    • an ultrasound scan, depending on local expertise.

  • If inflammatory markers are not raised, think about the possibility of alternative diagnoses.


Non-surgical managementof acute diverticulitis (1)

  • For people with acute diverticulitis who are systemically well:

    • consider a no antibiotic prescribing strategy

    • offer simple analgesia, for example paracetamol

    • advise the person to re‑present if symptoms persist or worsen.

  • Offer an antibiotic prescribing strategy if the person with acute diverticulitis is systemically unwell, is immunosuppressed or has significant comorbidity.

  • Offer oral antibiotics if the person with acute diverticulitis is systemically unwell but does not meet the criteria for referral for suspected complicated acute diverticulitis.

  • Offer intravenous antibiotics to people admitted to secondary care with suspected complicated acute diverticulitis.

    • manage suspected sepsis 

    • Review intravenous antibiotics within 48 hours or after scanning if sooner and consider stepping down to oral antibiotics where possible.

    • if the person has CT-confirmed uncomplicated acute diverticulitis, review the need for antibiotics and discharge them depending on any co-existing medical conditions.


Diverticular diasease - antimicrobial prescribing

diverticulad disease prescribing 1.png

Choice of antibiotic for adults aged 18 years and over

with suspected or confirmed acute diverticulitis

diverticulad disease prescribing 2.png

Information for people with acute diverticulitis (1)

Give people with acute diverticulitis, and their families and carers where appropriate, verbal and written information on:

  • diet and lifestyle

  • the course of acute diverticulitis and likelihood of complicated disease or recurrent episodes

  • symptoms

  • when and how to seek further medical advice

  • possible investigations and treatments

  • risks of interventions and treatments, including antibiotic resistance, and how invasive these are

  • role of surgery and outcomes (postoperative bowel function and symptoms)


Lifestyle advice for people with diverticulosis and diverticular diasease

Divert lifestyle.png

1. Diverticular disease : diagnosis and management

NICE guideline NG147

Published  27 November 2019


2. Painter NS, Burkitt DP.

Diverticular disease of the colon: a deficiency disease of Western civilization.

Br Med J. 1971 May 22;2(5759):450-4



3. Andersen JC, Bundgaard L, Elbrønd H, et al.

Danish national guidelines for treatment of diverticular disease.

Dan Med J. 2012 May;59(5):C4453.



4. Wijarnpreecha K, Ahuja W, Chesdachai S, et al.

Obesity and the risk of colonic diverticulosis: a meta-analysis.

Dis Colon Rectum. 2018 Apr;61(4):476-83



5. Aune D, Sen A, Leitzmann MF, et al.

Body mass index and physical activity and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies.

Eur J Nutr. 2017 Dec;56(8):2423-38



6. Aune D, Sen A, Leitzmann MF, et al.

Tobacco smoking and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies.

Colorectal Dis.2017 Jul;19(7):621-33



7. Lin OS, Soon MS, Wu SS, et al.

Dietary habits and right-sided colonic diverticulosis.

Dis Colon Rectum. 2000 Oct;43(10):1412-8.



8. Bode MK, Karttunen TJ, Makela J, et al.

Type I and III collagens in human colon cancer and diverticulosis.

Scand J Gastroenterol. 2000 Jul;35(7):747-52.



9. Bassotti G, Battaglia E, Spinozzi E, et al.

Twenty-four hour recordings of colonic motility in patients with diverticular disease: evidence for abnormal motility and propulasive activity.

Dis Colon Rectum. 2001 Dec;44(12):1814-20



10. Leganger J, Søborg MK, Mortensen LQ, et al.

Association between diverticular disease and Ehlers-Danlos syndrome: a 13-year nationwide population-based cohort study.

Int J Colorectal Dis. 2016 Dec;31(12):1863-7



11. Hauer-Jensen M, Bursac Z, Read RC.

Is herniosis the single etiology of Saint's triad?

Hernia. 2009 Feb;13(1):29-34


Ireland notes.png

CPD Quiz and Certificate

This activity attracts 1,0 CPD point


Scroll down the box above to view its entire content

All users who successfully complete the quiz are e-mailed a copy of their personalised CPD certificate.