• Clinical science

Acute abdomen


The acute abdomen is a surgical emergency characterized by sudden onset of severe abdominal pain and tenderness and muscular rigidity. Because of the severe pain and potentially life-threatening conditions associated with it (e.g., abdominal aneurysm rupture), rapid diagnosis and management are crucial. Differential diagnoses should be ruled out with a thorough physical examination, followed by laboratory tests and imaging, such as ultrasound, x-ray, or CT. Management depends on the specific diagnosis and ranges from medical treatment to emergency surgical intervention.

Differential diagnoses

Pain location Causes Typical findings Laboratory tests Next diagnostic step


  • Recent biliary or systemic infection
  • Fever, malaise, weight loss
  • Tender hepatomegaly
  • Ultrasound


  • History of recent trauma
  • Shock
  • Ultrasound (FAST exam)
  • Ultrasound
  • CT


  • X-ray or CT
  • Ultrasound or CT


  • History of abdominal surgery
  • Bloating
  • No bowel activity
  • Progressive nausea and vomiting (late finding)
  • Abdominal x-ray
  • CT with angiography

Radiating to the flanks and back

  • Ultrasound

Lower abdomen

  • Ultrasound
  • Amenorrhea
  • Vaginal bleeding
  • Hypotension (if ruptured)

Any woman of child-bearing age presenting with abdominal pain must have hCG checked!


The differential diagnoses listed here are not exhaustive.

  • 1. O'Connell TX. USMLE Step 2 Secrets. Elsevier Saunders; 2013.
  • 2. Mavilia MG, Molina M,Wu GY. The Evolving Nature of Hepatic Abscess: A Review. J Clin Transl Hepatol. 2016; 4(2). doi: 10.14218/jcth.2016.00004.
  • 3. Ahmed M. Acute cholangitis - an update. World J Gastrointest Pathophysiol. 2018; 9(1): pp. 1–7. doi: 10.4291/wjgp.v9.i1.1.
last updated 12/03/2019
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