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Practice Clinical updates

Acute appendicitis

BMJ 2017; 357 doi: (Published 19 April 2017) Cite this as: BMJ 2017;357:j1703
  1. Daniel L H Baird, surgical registrar and research fellow1 2,
  2. Constantinos Simillis, surgical registrar1,
  3. Christos Kontovounisios, locum consultant surgeon and honorary senior lecturer1 2 3,
  4. Shahnawaz Rasheed, consultant surgeon and clinical senior lecturer1 2 3,
  5. Paris P Tekkis, consultant surgeon and professor of colorectal surgery1 2 3
  1. 1Department of Colorectal Surgery, Royal Marsden Hospital, London SW3 6JJ, UK
  2. 2Department of Surgery and Cancer, Imperial College, London
  3. 3Department of Colorectal Surgery, Chelsea and Westminster Hospital, London
  1. Correspondence to: S Rasheed Shahnawaz.Rasheed{at}

What you need to know

  • Around half of patients with acute appendicitis will display the typical clinical features

  • Diagnosis is made on the basis of history and examination supported by blood tests and imaging in hospital

  • Appendicitis is more likely if there is an elevated white cell count, C reactive protein concentration, granulocyte count, or proportion of polymorphonuclear cells

  • Laparoscopic appendicectomy offers a reduced risk of wound infection, reduced rate of negative appendicectomy, less postoperative pain, shorter length of hospital stay, and quicker return to work and full function

  • 1% of appendicectomies reveal a neoplasm

Acute appendicitis is the most common abdominal surgical emergency in the world, with around 50 000 and 300 000 acute appendicectomies performed annually in the UK and in the US respectively.12 However, its incidence is falling for unknown reasons.34

This clinical update provides information on how patients may present and what investigations and treatments are available.

Who is affected?

Acute appendicitis can affect people of any age but is most common between the ages of 10 and 20 years.45 It is more common in males, although females are twice as likely to undergo an appendicectomy.67 The lifetime risk of acute appendicitis is 8.6% in males and 6.9% in females; the lifetime appendicectomy rate is 12% in males and 23% in females.67 Perforation is found in 13-20% of patients with acute appendicitis.89

What causes appendicitis?

The aetiology remains uncertain,7910 but possible causes include luminal obstruction blocking the escape of mucosal secretions and leading to an increase in pressure, causing engorgement and stasis that can lead to necrosis and eventually perforation.79 Faecoliths, foreign bodies, malignancy, and lymphoid hyperplasia during an infection are described as possible causes of luminal obstruction.91112 There is no known genetic cause of acute appendicitis, but increased …

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