What is the appropriate history of present illness (HPI) for a patient presenting with abdominal pain?

History of Present Illness for Abdominal Pain

When obtaining an HPI for abdominal pain, immediately assess for life-threatening conditions by asking about pain out of proportion to physical findings (mesenteric ischemia), cardiovascular risk factors, and timing of symptom onset, as every hour of delay in diagnosing mesenteric ischemia increases mortality. 1

Critical Red Flag Questions (Ask First)

• Pain severity relative to examination findings: Severe pain out of proportion to physical findings is the hallmark of acute mesenteric ischemia and requires immediate imaging 1, 2
• Cardiovascular history: History of atrial fibrillation, recent MI, or cardiovascular disease raises suspicion for mesenteric ischemia, particularly in elderly women 1
• Abdominal rigidity: Presence of rigidity indicates peritonitis requiring immediate surgical evaluation 1, 2
• Pregnancy status: Beta-hCG testing is mandatory in all women of reproductive age before any imaging 2, 3

Essential HPI Components by System

Pain Characteristics

• Location: Right lower quadrant suggests appendicitis; right upper quadrant suggests cholecystitis; left lower quadrant suggests diverticulitis 2, 4
• Onset and duration: Acute onset (hours) versus subacute (days) helps narrow differential 3
• Quality and severity: Sharp, cramping, or constant pain patterns 4
• Radiation: Pain radiating to back suggests pancreatitis or nephrolithiasis 5

Associated Symptoms

• Fever: Raises suspicion for intra-abdominal infection, abscess, or conditions requiring immediate surgical/medical attention 5, 1
• Tachycardia: Most sensitive early warning sign of surgical complications and should trigger urgent investigation even before other symptoms develop 2
• Tachypnea: Combined with fever and tachycardia predicts serious complications including anastomotic leak, perforation, or sepsis 2
• Constipation and distension: Strongly suggest bowel obstruction 4
• Diarrhea: Concomitant diarrhea with abdominal pain has lower diagnostic yield on CT (11% management change versus 53% without diarrhea) 5
• Occult blood in stool: Early finding in mesenteric ischemia 1

Past Medical and Surgical History

• Recent surgery: Post-operative patients require heightened suspicion for anastomotic leak or abscess 2
• Post-bariatric surgery: These patients often present with atypical symptoms and classic peritoneal signs are frequently absent 2
• Immunocompromised status: Neutropenic patients may have masked signs of abdominal sepsis with delayed diagnosis and high mortality 1, 2
• Inflammatory bowel disease: Fever with known Crohn's disease raises possibility of abscess or phlegmon 5

Special Population Considerations

Elderly Patients

• Laboratory tests may be normal despite serious infection, making clinical history even more critical 1, 2
• Higher likelihood of malignancy, diverticulitis, and vascular causes 2
• Atypical presentations are common 4

Immunocompromised Patients

• Typical signs of abdominal sepsis may be masked 1
• Normal laboratory values do not exclude serious infection 2
• Diagnosis may be delayed with associated high mortality 1

Common Pitfalls to Avoid

• Do not rely on absence of peritonitis to exclude bowel ischemia: Patients with sigmoid volvulus often lack peritoneal signs despite established ischemia due to chronic distension masking the examination 2
• Normal lactate does not exclude internal herniation or early ischemia 2
• Anorexia has little predictive value for appendicitis despite being commonly asked 4
• In elderly patients, normal laboratory tests do not exclude serious infection 1, 2

Diagnostic Probability Context

Approximately one-third of ED presentations with acute abdominal pain have appendicitis, one-third never have a diagnosis established, and one-third have other documented pathology including acute cholecystitis (9-11%), small bowel obstruction (4-5%), pancreatitis, renal colic, perforated peptic ulcer, diverticulitis, and cancer 1, 4