What is the initial step in evaluating a patient with abdominal pain?

History Taking for Patients with Abdominal Pain

The initial step in evaluating a patient with abdominal pain should be a detailed, systematic history focusing on pain characteristics, associated symptoms, and risk factors to guide subsequent physical examination and diagnostic testing. 1

Key Components of History Taking

Pain Characteristics (PQRST Framework)

• Provocation/Palliation: What makes the pain better or worse?
• Quality: How does the patient describe the pain? (e.g., sharp, dull, cramping)
• Region/Radiation: Where is the pain located and does it radiate?
• Severity: How severe is the pain on a scale of 1-10?
• Timing: When did the pain start? Is it constant or intermittent?

Associated Symptoms

• Gastrointestinal symptoms: nausea, vomiting, diarrhea, constipation, melena, hematochezia
• Urinary symptoms: dysuria, frequency, hematuria
• Gynecological symptoms (in women): vaginal discharge, menstrual history, pregnancy status
• Systemic symptoms: fever, weight loss, anorexia

Alarming Clinical Signs

• Tachycardia, fever, hypotension, respiratory distress, and decreased urine output require immediate attention 1
• Persistent epigastric pain (especially in patients with history of laparoscopic Roux-en-Y gastric bypass) may indicate internal hernia 1
• Persistent crampy/colicky abdominal pain with vomiting and abnormal stool transit suggests bowel obstruction 1

Location-Based Approach

The location of pain provides valuable diagnostic clues:

• Right Upper Quadrant: Consider gallbladder pathology (ultrasonography is preferred initial imaging) 2, 1
• Right Lower Quadrant: Strongly suggests appendicitis (CT with IV contrast is first-line imaging) 1, 3
• Left Lower Quadrant: Consider diverticulitis (CT with IV contrast is recommended) 2, 1
• Diffuse Pain: Broader differential including bowel obstruction, mesenteric ischemia, or peritonitis 2, 1

Special Populations

Elderly Patients

• May present with atypical symptoms
• Normal white blood cell count does not exclude serious pathology 1
• Higher risk for mesenteric ischemia (especially with atrial fibrillation or history of arterial emboli) 1

Pregnant Patients

• Require prompt diagnosis with low threshold for intervention
• Ultrasound should be first-line imaging 1
• Always position with left lateral tilt to prevent aortocaval compression 1

Immunocompromised Patients

• Typical signs of abdominal sepsis may be masked 2
• Higher mortality rate with delayed diagnosis 2

Laboratory Evaluation

After history taking, appropriate laboratory tests should include:

• Complete blood count
• Comprehensive metabolic panel
• C-reactive protein (CRP) and/or procalcitonin
• Serum lactate levels
• Blood gas analysis
• Urinalysis
• Pregnancy test in women of childbearing age 1

Common Pitfalls to Avoid

1. Relying solely on white blood cell count to rule out serious pathology
2. Delaying imaging when clinical suspicion is high
3. Overlooking gynecological causes in women of reproductive age
4. Failing to recognize atypical presentations in elderly patients
5. Withholding necessary imaging in pregnant patients due to radiation concerns 1

Remember that a thorough history is crucial as it guides the physical examination, laboratory testing, and imaging studies. The American College of Radiology recommends different imaging studies based on pain location, with CT being the preferred modality for nonlocalized abdominal pain due to its superior diagnostic yield 2, 1.