Differential diagnosis of acute abdomen

1. Big picture

Acute abdomen is not one disease. It is a clinical emergency syndrome: sudden or rapidly progressive abdominal pain that may require urgent medical, surgical, gynecological, urological, or vascular intervention.

The exam approach is:

Do not start with rare causes.
First ask: Is the patient unstable? Is there peritonitis? Is there ischemia? Is there obstruction? Is this a non-abdominal mimic?

The safest oral exam sequence:

ABC assessment
→ vital signs and shock/peritonitis search
→ focused history and examination
→ pregnancy test in women of reproductive age
→ blood tests + urinalysis + ECG when indicated
→ imaging guided by location/severity
→ early surgical/gynecological/urological consultation if red flags

For adults with acute nonlocalized abdominal pain, CT abdomen/pelvis with IV contrast is usually appropriate and often the optimal imaging modality, while ultrasound is especially useful for biliary, pelvic, and ascites-related causes. ([acsearch.acr.org][1])

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