Clinical features and differentials

Sudden onset of severe abdominal pain whose characteristics depend on the cause. For instance:

• Colic abdominal pain reflecting a hollow viscus pathology.
• Rebound tenderness and muscle guarding reflect peritonism.
• Features of hypovolemic shock reflect intra abdominal vascular accidents.
• Severe abdominal pain disproportional to clinical features reflect bowel ischaemia.

Site of the pain reflects a possible pathology of underlying anatomical structures as portrayed in the diagram below:

Associated features of acute abdomen include nausea, vomiting, abdominal distension and hemodynamic instability.