Character and onset of Colicky pain Obstructive process: bowel obstruction / ureteric calculus / cholecystitis. Sustained & worsening appendicitis, diverticulitis. Gradual onset Pancreatitis. Sudden onset Perforated hollow viscus. Other factors that help in the diagnosis: History of previous intraadbominal disease. History of previous abdominal surgery. Family history. Menstrual history. Physical examination: Observation of body habitus and facial expression. Suspect Peritonitis when there is unwillingness to change body position. - patient is in flexion with knees drawn up. - shallow breathing. - Inspection look for hernial bulges. - masses. - distention of abdomen. - areas of inflammation. Palpation look for guarding / rigidity. Palpate all quadrants gently. Start palpation from quadrant with least symptomatology Closely examine for mass. Rebound tenderness. Auscultation for bruit and bowel sounds. Rectal examination for pelvic tenderness. for obstructing rectal growth. Before performing any major investigation, it is essential to resuscitate the patient and correct the hydration and electrolyte imbalance if any. In a woman do not forget gynecologic causes of acute abdomen (see Chapter on Abdominal pain in women (Page DFH-OBG-1 & 2). Pelvic inflammatory disease. Ectopic pregnancy. Tubo ovarian cysts. Torsion, hamorrhage, abscess. Mittelschmerz disease. Also consider urological causes of acute abdomen: Renal, perirenal or bladder infections. Obstructions of ureter, renal pelvis or bladder. Acute intrascrotal events. Exclude non-surgical causes of acute abdomen: Metabolic Diabetic ketoacidosis. Porphyria. Adrenal insufficiency. Uremia/hypercalcemia. Neurogenic Herpes zoster. Spinal cord tumor/infection. Nerve root compression. Abdominal wall epilepsy. Cardiopulmonary Pneumonia. Myocardial infarction. Empyema. Costochondritis. Toxic Insect bites. Venoms. Lead poisoning. Drugs. Miscellaneous Hemolytic crisis. Rectus sheath hematoma.