B5. Acute appendicitis


For introduction, epidemiology, etiology, and pathomechanism, see the corresponding pathology 2 topic.

Clinical features

The classical clinical features of acute appendicitis are:

  • Initial diffuse periumbilical pain which evolves into peritonitic pain in the right lower quadrant
  • Anorexia (decreased appetite)
  • Nausea and vomiting

Other possible symptoms include fever and abnormal bowel habits.

Various physical signs may be positive in acute appendicitis, including McBurney point tenderness, Rovsing sign, psoas sign, and obturator sign (topic A25). Because of the localised peritonitis over the appendix, peritonitis signs like guarding, rebound tenderness, and heel-drop test may be positive and elicit pain in the right lower quadrant.

Diffuse peritonitis may be a sign of perforated appendicitis.

There is considerable anatomical variation in the location of the free end of the appendix, which will influence the site of pain and findings on physical examination. A retrocaecal appendix may not cause localised tenderness in the right lower quadrant (because localised peritonitis does not occur). A pelvic appendix may cause localised tenderness well below McBurney’s point.

Diagnosis and evaluation

A normal WBC count is unlikely in the case of acute appendicitis, as an (at least) mild leukocytosis is present in > 80% of cases. The higher the WBC count, the higher the chance for gangrenous or perforated appendicitis. CRP is also frequently elevated.

In some countries (like Norway), imaging is usually not performed if the clinical presentation is very suspicious for acute appendicitis. If imaging is to be performed, low-dose abdominal CT with contrast or abdominal ultrasound are the modalities of choice. These may reveal suspicious features such as thickening and enhancement of the appendiceal wall. Imaging will also reveal features of perforation if present.

Only histology can confirm the diagnosis of appendicitis.


Immediate laparoscopic appendectomy is the gold standard for management of acute appendicitis. In case of perforated appendicitis, the patient may proceed directly to surgery as usual, or surgery may be postponed temporarily while the patient receives antibiotics and percutaneous drainage. Laparoscopic appendectomy is a relatively simple surgical procedure and is most surgeons’ first surgical procedure. It’s sometimes said that that the function of the appendix in the modern times is to allow young surgeons to improve their surgical technique.

Studies have shown that antibiotic therapy can be as effective as surgery for managing the initial presentation of appendicitis. However, these studies also conclude that this carries with it moderate risk of recurrence and missed neoplasms. As such, surgery remains the first choice.

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A26. Differential diagnosis of bloody stool. The significance of rectal digital investigation

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B8. Clinical manifestations of gallstone disease. Laparoscopic cholecystectomy

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