What are the next steps in the further workup and management of a patient presenting with abdominal pain?

Evaluation and Management of Abdominal Pain

CT scan with IV contrast is the first-line imaging modality for patients presenting with nonlocalized abdominal pain, as it provides the highest diagnostic accuracy and can significantly alter diagnosis and management in over 50% of cases. 1, 2

Initial Clinical Assessment

When evaluating a patient with abdominal pain, focus on:

• Pain characteristics: Onset, location, quality, severity, timing, and aggravating/alleviating factors
• Associated symptoms: Fever, vomiting, changes in bowel habits, urinary symptoms
• Alarming clinical signs: Tachycardia, fever, hypotension, respiratory distress, decreased urine output 1, 2

Diagnostic Approach

Laboratory Testing

• 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, 2

Imaging Selection

1. Nonlocalized Abdominal Pain:

   • First-line: CT abdomen and pelvis with IV contrast 1, 2
   • CT significantly improves diagnostic certainty (from 70.5% to 92.2%) and changes management in 42% of patients 1
   • Oral contrast is not always necessary and may delay scan acquisition 1

2. Right Upper Quadrant Pain:

   • First-line: Ultrasound (sensitivity 96.7%, specificity 85.7%) 2
   • Consider CT if ultrasound is inconclusive

3. Female Patients with Pelvic Pain:

   • First-line: Pelvic ultrasound 3, 4
   • Consider CT if gynecologic disorder is not initially suspected or ultrasound findings are equivocal 5
   • For pregnant patients with pelvic pain, ultrasound must be performed to exclude ectopic pregnancy 6

4. Suspected Mesenteric Ischemia:

   • CT angiography (CTA) without delay - includes arterial and venous phases
   • Oral contrast is not indicated and may be harmful 2

Management Approach

Pain Management

• Initiate analgesic management as soon as possible
• Diagnosis of pain etiology should not delay administration of analgesics 1
• For crampy pain (particularly when exacerbated by meals), consider antispasmodics as first-line treatment 2

Fluid Resuscitation

• Correct fluid and electrolyte abnormalities 2
• For patients with septic shock, administer vasopressors if fluid resuscitation fails to restore mean arterial pressure 1

Antibiotic Therapy

• Administer only when infection is suspected or confirmed
• Clinical improvement should be seen within 3-5 days after starting antibiotics 2

Surgical Consultation

• Early surgical consultation is essential for patients with peritoneal signs, suspected bowel obstruction, or mesenteric ischemia
• Source control is critical in managing intra-abdominal infections 1

Special Considerations

Pregnant Patients

• Ultrasound should be first-line imaging
• CT should be reserved for selected cases when benefits outweigh risks
• Position patient with left lateral tilt to prevent aortocaval compression 2

Elderly Patients

• May present with atypical symptoms and less pronounced physical findings
• Higher risk of mortality with delayed diagnosis
• Consider early imaging and surgical consultation 1

Chronic Pain Patients

• Assess for risk factors for transition from acute to chronic pain
• Consider multimodal pain management approaches 1
• For patients with irritable bowel syndrome, consider psychological therapies when symptoms have not improved after 12 months of drug treatment 1

Common Pitfalls to Avoid

• Relying solely on white blood cell count: Normal values do not exclude serious pathology 2
• Overreliance on plain films: Limited value in non-traumatic abdominal pain evaluation 2
• Delaying imaging: Every 6 hours of delay in CTA doubles mortality in mesenteric ischemia 2
• Failing to consider gynecologic causes: In women of reproductive age, always consider gynecologic pathology 3, 5, 4
• Delaying analgesics: Pain management should not be withheld while awaiting diagnosis 1

By following this systematic approach to the evaluation and management of abdominal pain, clinicians can ensure timely diagnosis and appropriate treatment, ultimately improving patient outcomes.