What is the appropriate work-up for a patient presenting with stomach pain?

Appropriate Work-up for a Patient Presenting with Stomach Pain

CT scan of the abdomen and pelvis with IV contrast is the most appropriate initial imaging study for patients presenting with nonlocalized abdominal pain, as it provides the highest sensitivity and specificity for detecting a wide range of pathologies. 1

Initial Assessment

History - Focus on:

• Pain characteristics: location, onset, duration, quality, severity, radiation
• Associated symptoms: fever, nausea, vomiting, diarrhea, constipation
• Aggravating/alleviating factors
• Prior abdominal surgeries or conditions

Physical Examination - Key Elements:

• Vital signs (especially fever, which raises concern for infection/abscess)
• Abdominal examination: tenderness, guarding, rebound, distension
• Specific quadrant findings that may guide further workup

Laboratory Tests:

• Complete blood count (CBC) - to assess for leukocytosis suggesting infection
• Comprehensive metabolic panel - to evaluate liver and kidney function
• C-reactive protein and/or ESR - inflammatory markers
• Urinalysis - to rule out urinary tract causes
• Lipase - if pancreatitis is suspected
• Pregnancy test - for all women of reproductive age

Imaging Algorithm Based on Pain Location

For Nonlocalized Abdominal Pain:

• CT abdomen and pelvis with IV contrast is the first-line imaging study 1
  • Provides high sensitivity for detecting various pathologies
  • Changed leading diagnosis in 49% of patients and admission status in 24% 1
  • Particularly valuable when clinical diagnosis is uncertain

For Right Upper Quadrant Pain:

• Ultrasonography is the initial imaging test of choice 1
  • Highly sensitive for gallbladder pathology, hepatic lesions
  • If ultrasound is equivocal, proceed to CT with IV contrast

For Lower Quadrant Pain (Right or Left):

• CT abdomen and pelvis with IV contrast is recommended 1
  • Superior for detecting appendicitis, diverticulitis, and other inflammatory conditions
  • More sensitive than ultrasound for appendicitis (94% vs 76%) 1

Special Populations

Pregnant Patients:

• Ultrasound should be the first-line imaging test (sensitivity 96.7%, specificity 85.7%) 2
• If ultrasound is inconclusive, MRI without contrast is preferred over CT 2
• CT should only be used after other non-radiation studies have been exhausted 2

Elderly Patients:

• More aggressive imaging is warranted as they may present with atypical symptoms
• Laboratory tests may be normal despite serious infection 1
• Consider CT earlier in the diagnostic algorithm
• Ensure ECG is performed (only 39% of elderly with abdominal pain receive one) 3

Common Pitfalls to Avoid

1. Relying on plain radiographs: Conventional radiography has limited diagnostic value in the assessment of abdominal pain and should not be used as the initial imaging study 1, 4

2. Delaying imaging in patients with fever: When fever is present with abdominal pain, quick definitive diagnosis is needed as this raises concern for intra-abdominal infection or abscess 1

3. Overreliance on laboratory tests: Laboratory tests alone are insufficient to discriminate urgent from non-urgent diagnoses 5

4. Missing extra-abdominal causes: Consider conditions like pneumonia that can present with abdominal pain 1

5. Inadequate pain control: Administration of analgesics decreases pain intensity without affecting diagnostic accuracy 5

Conclusion for Clinical Practice

The diagnostic approach to abdominal pain should be guided by pain location, associated symptoms (particularly fever), and patient factors. While clinical assessment remains essential, imaging plays a crucial role in establishing the diagnosis and guiding management. CT with IV contrast provides the most comprehensive evaluation for nonlocalized abdominal pain, while ultrasound is preferred for right upper quadrant pain and in pregnant patients.