Differential Diagnosis :

Only after ruling out perforated peptic ulcer under the circumstances look for possible acute pancreatitis (serum amylase +++) or other causes of acute abdomen.

Management as a Family Practitioner:
Must be able to diagnose this by clinical exam
N.G. suction
Correct dehydration and electrolyte balance in preparation for surgery (closure of perforation with or without surgery for Acid Peptic disease).