What is the best initial diagnostic step for a male patient in his 20s with severe epigastric pain, diffuse tenderness, sluggish bowel sounds, leukocytosis (high White Blood Cell (WBC) count), and elevated amylase levels?

Best Initial Diagnostic Step for Acute Epigastric Pain with Elevated Amylase

Abdominal CT scan is the best initial diagnostic step for this patient with severe epigastric pain, diffuse tenderness, sluggish bowel sounds, leukocytosis, and elevated amylase. 1

Clinical Presentation Analysis

The patient presents with:

• Severe epigastric pain of sudden onset (6 hours)
• Diffuse abdominal tenderness
• Sluggish bowel sounds
• Leukocytosis (high WBC count)
• Elevated amylase (300)

This constellation of symptoms raises concern for several serious intra-abdominal pathologies including:

• Acute pancreatitis
• Perforated peptic ulcer
• Mesenteric ischemia
• Bowel obstruction

Diagnostic Approach

Why CT is the Best Initial Test

1. Superior Diagnostic Capability: CT scan provides comprehensive evaluation of all abdominal organs and can identify the cause of epigastric pain with high sensitivity and specificity 1

2. Guideline Support: The World Journal of Emergency Surgery guidelines recommend CT as the first-line imaging modality for suspected perforated peptic ulcer, stating: "In patients with acute abdomen from suspected perforated peptic ulcer, we recommend a CT scan imaging" (Strong recommendation) 1

3. Detection of Multiple Pathologies: CT can simultaneously evaluate for:

   • Pancreatitis and its complications
   • Perforated viscus (free air)
   • Bowel obstruction
   • Mesenteric ischemia
   • Inflammatory conditions

4. Laboratory Context: The elevated amylase (300) suggests possible pancreatic involvement, but this level can also be seen in other conditions including perforated peptic ulcer, mesenteric ischemia, and intestinal obstruction 1

Why Other Options Are Less Optimal

1. Erect Chest X-ray (Option A):

   • While traditionally used to detect free air from perforated viscus, it has limited sensitivity (30-85% for perforations) 1
   • Cannot adequately evaluate other potential causes of the patient's presentation
   • The World Journal of Emergency Surgery recommends this only "in case a CT scan is not promptly available" 1

2. Abdominal X-ray (Option B):

   • Low sensitivity and specificity for most acute abdominal conditions 1
   • Limited value in detecting early signs of pancreatitis or mesenteric ischemia 1
   • "Plain radiographs are often not sufficiently sensitive and specific to allow for a definitive diagnosis" 1

3. Abdominal Ultrasound (Option D):

   • Operator-dependent with limited visualization in patients with bowel gas or obesity
   • Less sensitive than CT for detecting free air or subtle inflammatory changes 1
   • Cannot reliably evaluate the entire pancreas, retroperitoneum, or mesentery

Clinical Reasoning

The combination of sudden-onset severe epigastric pain, diffuse tenderness, sluggish bowel sounds, leukocytosis, and elevated amylase requires prompt and comprehensive evaluation. While the elevated amylase suggests pancreatic involvement, the clinical picture could represent several serious conditions:

1. Perforated peptic ulcer: Can present with sudden epigastric pain, diffuse tenderness, and elevated amylase due to irritation of the pancreas 1

2. Acute pancreatitis: Consistent with the elevated amylase, though the sudden onset and diffuse tenderness may suggest a more complicated picture

3. Mesenteric ischemia: Can present with pain out of proportion to physical findings, leukocytosis, and elevated amylase 2

4. Bowel obstruction with possible strangulation: Suggested by sluggish bowel sounds and diffuse tenderness 1

Important Considerations

• The patient's young age (20s) does not exclude serious pathology
• Diffuse tenderness may indicate peritonitis, which is concerning for perforation or advanced inflammation
• Sluggish bowel sounds suggest an evolving ileus, which can be secondary to any intra-abdominal inflammatory process
• CT should be performed with IV contrast when possible to optimize evaluation of vascular structures and organ perfusion 1

Given the acuity of presentation and concerning physical examination findings, obtaining a prompt and comprehensive diagnostic evaluation with CT is the most appropriate initial step to guide further management.