Which of the following are signs of an acute abdomen that warrant immediate evaluation?

The signs of an acute abdomen that warrant immediate evaluation include sudden onset abdominal pain, rigidity, and rebound tenderness. This combination of symptoms is highly indicative of potentially serious conditions such as appendicitis, peritonitis, or an intestinal obstruction. Sudden onset abdominal pain suggests a significant underlying issue that needs urgent assessment. Rigidity indicates that the abdominal muscles are tense, which may be a protective response to an underlying inflammatory process. Rebound tenderness occurs when pressure is applied to the abdomen and then quickly released, causing pain that is more pronounced with withdrawal. This is a classic sign of irritation of the peritoneum suggesting a serious condition that requires prompt medical attention.

Mild abdominal discomfort on a consistent basis often does not indicate an acute condition needing immediate evaluation. Low-grade fever and nausea can be associated with many non-emergent situations and do not necessarily point to an acute abdomen. Diarrhea and fatigue might suggest gastrointestinal issues, but they are not specific enough to indicate the urgent nature of an acute abdomen without other signs of distress.