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