The Acute Abdomen
Sudden abdominal pain reflects one of two mechanisms: a hollow viscus obstructing and distending (colic) or the peritoneum being inflamed and irritated (peritonism), and telling them apart, not naming a diagnosis, decides whether a patient needs the theatre now.
First principles
The acute abdomen is a mechanism, not a diagnosis
'Acute abdomen' describes sudden-onset abdominal pain severe enough to suggest a condition that may need urgent intervention; it is a presentation, covering dozens of underlying causes. What matters first is not naming the exact diagnosis but classifying the pain by its underlying mechanism, because that classification predicts urgency and drives the immediate management before imaging or a definitive diagnosis is even available.
Educational content pending clinical review. Not medical advice.