What is the initial assessment and management approach for a patient presenting with abdominal pain?

Initial Assessment and Management of Abdominal Pain

The initial assessment of abdominal pain should follow a step-up approach beginning with clinical and laboratory examination, followed by appropriate imaging based on pain location, with computed tomography (CT) being the preferred modality for nonlocalized pain and ultrasonography for right upper quadrant pain. 1

Clinical Assessment

History - Key Elements to Obtain:

• Pain characteristics:
  • Location and radiation
  • Onset (sudden vs. gradual)
  • Duration and progression
  • Quality (sharp, dull, cramping)
  • Aggravating/alleviating factors
• Associated symptoms:
  • Nausea/vomiting
  • Changes in bowel habits (constipation, diarrhea)
  • Last bowel movement
  • Fever
  • Urinary symptoms
• Past medical history:
  • Previous abdominal surgeries (85% sensitivity for adhesive small bowel obstruction) 1
  • History of diverticulitis, inflammatory bowel disease
  • History of gallstones, pancreatitis
  • Recent weight loss (concerning for malignancy)
  • Comorbidities affecting presentation

Physical Examination - Critical Components:

• Vital signs (fever, tachycardia, hypotension)
• General appearance (distress level, positioning)
• Abdominal examination:
  • Inspection for distension, visible peristalsis
  • Auscultation for bowel sounds (hyperactive or absent)
  • Palpation for tenderness, guarding, rebound
  • Percussion for tympany or dullness
  • Assessment for peritoneal signs
• Rectal examination when appropriate
• Pelvic examination in women of reproductive age

Laboratory Testing:

• Complete blood count (elevated WBC suggests inflammation/infection)
• Basic metabolic panel
• Liver function tests
• Lipase/amylase (for suspected pancreatitis)
• Urinalysis
• Beta-hCG in all women of reproductive age 1
• C-reactive protein (elevated CRP is a significant predictor for hospital admission) 2

Imaging Approach Based on Pain Location

Nonlocalized Abdominal Pain:

• CT abdomen and pelvis with contrast is the preferred initial imaging modality 1
• CT has been shown to change the leading diagnosis in 49% of patients and management plans in 42% 1

Right Upper Quadrant Pain:

• Ultrasonography is the initial imaging test of choice 1
• Consider CT if ultrasonography is inconclusive

Right or Left Lower Quadrant Pain:

• CT abdomen and pelvis with contrast is recommended 1
• Ultrasonography may be considered as initial imaging in young patients or pregnant women

Suspected Bowel Obstruction:

• CT abdomen and pelvis with contrast is the preferred modality 1
• Plain radiography may be useful for suspected bowel obstruction or perforated viscus 1

Special Considerations

Fever with Abdominal Pain:

• Raises suspicion for intra-abdominal infection or abscess
• CT with IV contrast is the preferred imaging modality 1
• Elderly patients with fever and abdominal pain warrant expedited evaluation as laboratory tests may be normal despite serious infection 1

Pregnant Patients:

• Ultrasonography should be the initial imaging modality
• MRI can be considered when ultrasonography is inconclusive 1

Immunocompromised Patients:

• Require expedited evaluation as typical signs of abdominal sepsis may be masked 1
• Lower threshold for advanced imaging

Management Approach

1. Resuscitation if hemodynamically unstable
2. Pain control
3. NPO (nothing by mouth) status if surgical intervention is anticipated
4. IV fluid resuscitation
5. Empiric antibiotics if infection is suspected
6. Surgical consultation for:
   • Peritoneal signs
   • Bowel obstruction
   • Suspected appendicitis
   • Perforated viscus
   • Ischemic bowel

Common Pitfalls to Avoid

• Relying solely on conventional radiography, which has limited diagnostic value for most causes of abdominal pain 1
• Delaying surgical consultation when peritoneal signs are present
• Failing to perform pregnancy testing in women of reproductive age
• Overlooking extra-abdominal causes of abdominal pain (e.g., pneumonia, myocardial infarction)
• Excessive radiation exposure from repeated CT scans without considering alternative imaging modalities
• Discharging patients without adequate follow-up plans when diagnosis remains uncertain

By following this systematic approach to abdominal pain assessment and management, clinicians can efficiently narrow the differential diagnosis and provide timely, appropriate care to minimize morbidity and mortality.