What is the initial approach to evaluating a patient with abdominal pain, including history taking and diagnostic tests?

History Taking in Abdominal Pain: A Systematic Approach

Critical Initial Questions

Begin by asking about the last bowel movement and passage of gas—this single question has 85% sensitivity and 78% specificity for predicting adhesive small bowel obstruction if the patient has prior abdominal surgery. 1

Essential Historical Elements

Timing and Onset:

• Document symptom duration (hours to days) as this predicts severity—patients in Western countries typically present 3-4 days after onset, while acute presentations with peritonitis suggest already-established necrosis 1
• Sudden severe pain suggests perforation, vascular catastrophe, or volvulus requiring immediate intervention 2

Pain Characteristics:

• Colicky pain indicates bowel obstruction as the bowel attempts to overcome occlusion 1
• Pain out of proportion to physical findings is the hallmark of mesenteric ischemia and demands urgent evaluation 2
• Location guides diagnosis: right upper quadrant suggests hepatobiliary disease, right lower quadrant suggests appendicitis, left lower quadrant suggests diverticulitis 2, 3

Associated Symptoms:

• Vomiting occurs earlier and more prominently in small bowel obstruction versus large bowel obstruction 1
• The triad of abdominal pain, constipation, and vomiting (late sign) suggests sigmoid volvulus, especially if the patient reports previous episodes of distention (present in 30-41% of cases) 1
• Rectal bleeding with unexplained weight loss points toward colorectal cancer 1

Past Medical and Surgical History

Previous Abdominal Surgery:

• Any prior laparotomy makes adhesive obstruction the leading diagnosis (accounts for 55-75% of small bowel obstructions) 1
• Document the specific procedure and timing 1

Relevant Medical Conditions:

• Previous diverticulitis episodes suggest diverticular stenosis 1
• Chronic constipation history raises suspicion for dolichosigmoid and volvulus 1
• Personal history of sigmoid volvulus recurs in 30-40% of cases 1
• Cardiopulmonary, renal, or hepatic comorbidities increase surgical risk and influence management 1

Medications:

• Psychotropic medications cause chronic constipation predisposing to volvulus, particularly in elderly institutionalized patients 1
• Any drugs affecting peristalsis are critical for differentiating pseudo-obstruction from mechanical obstruction 1

Red Flags Requiring Immediate Escalation

Vital Sign Abnormalities:

• Tachycardia is the single most sensitive early warning sign of surgical complications and should trigger urgent investigation even before other symptoms develop 2, 3
• The combination of fever, tachycardia, and tachypnea predicts serious complications including anastomotic leak, perforation, or sepsis 2
• Hypotension or hemodynamic instability suggests bleeding or sepsis 2

Physical Examination Findings:

• Signs of peritonitis (rigid abdomen, rebound tenderness) require urgent surgical evaluation 2
• Abdominal distension with vomiting indicates bowel obstruction 2
• Asymmetric gaseous distention with emptiness of the left iliac fossa is pathognomonic for sigmoid volvulus, though challenging to detect 1
• Empty rectum on digital examination is classic for sigmoid volvulus 1

Special Population Considerations

Women of Childbearing Age:

• Always consider ectopic pregnancy, ovarian torsion, or pelvic inflammatory disease 2, 3
• Beta-hCG testing is mandatory before any imaging 2, 4, 3

Elderly Patients:

• The classic patient for sigmoid volvulus is elderly, institutionalized, and on psychotropic medications 1
• Symptoms may be atypical even with serious pathology 2, 3
• Higher likelihood of malignancy, diverticulitis, and vascular causes 2, 3

Post-Bariatric Surgery Patients:

• Often present with atypical symptoms where tachycardia is the most critical warning sign 2
• Classic peritoneal signs are frequently absent, and internal herniation should be considered even with normal lactate 2

Critical Pitfall to Avoid

The absence of peritonitis on examination does not exclude bowel ischemia—patients with sigmoid volvulus often lack peritoneal signs despite having established ischemia due to chronic distension masking the examination. 1 This delay in diagnosis can be catastrophic, so maintain high suspicion based on history alone.