What is the next step in managing a 15-year-old patient with persistent abdominal pain, migrating pain, and vomiting after food, with normal computed tomography (CT) abdomen and routine blood investigations?

Next Steps in Management

Given the persistent, migrating abdominal pain with postprandial vomiting in this 15-year-old with normal CT and labs, the next step is CT angiography (CTA) of the abdomen to evaluate for chronic mesenteric ischemia or median arcuate ligament syndrome, followed by upper endoscopy if vascular imaging is negative.

Immediate Diagnostic Priorities

CTA Abdomen and Pelvis with Arterial Phase

• CTA should be performed without delay as the gold standard for evaluating mesenteric vascular pathology in patients with chronic postprandial pain 1
• The study must include both arterial and portal venous phases to assess arterial stenosis and venous patency, with multiplanar reconstructions and 3-D rendering 1
• CTA has 95-100% sensitivity and specificity for detecting mesenteric vessel stenosis compared to digital subtraction angiography 1
• Peak systolic velocity cutoffs of 295 cm/s for the superior mesenteric artery (SMA) and 240 cm/s for the celiac artery indicate significant stenosis 1

Key Clinical Pattern Recognition

The combination of postprandial pain, persistent vomiting, and weight loss (implied by 2-month duration) forms the classic triad of chronic mesenteric ischemia in adolescents, though this can also occur from median arcuate ligament syndrome 1

Specific Vascular Pathologies to Evaluate

Median Arcuate Ligament Syndrome

• This is a critical consideration in young patients with postprandial pain and normal routine CT 1
• Requires mesenteric angiography in lateral projection during both inspiration and expiration if CTA suggests celiac compression 1
• CTA can accurately diagnose this as a cause of chronic ischemia 1

Superior Mesenteric Artery Stenosis

• Atherosclerotic disease is less common in adolescents but fibromuscular dysplasia or vasculitis should be considered 1
• The migrating nature of pain suggests intermittent vascular compromise affecting different bowel segments 1

If Vascular Imaging is Negative

Upper Endoscopy with Gastric Emptying Study

• Gastroparesis presents with postprandial vomiting, nausea, and abdominal pain 2
• Scintigraphy and 13C breath testing provide validated assessment of gastric emptying 2
• Endoscopy can identify gastritis, duodenitis, or peptic ulcer disease that may be missed on CT 1

Consider Functional Disorders

• If structural pathology is excluded, functional abdominal pain disorders become more likely 3
• However, the persistent vomiting and 2-month duration warrant thorough exclusion of organic disease first 4

Critical Pitfalls to Avoid

Do Not Assume Normal CT Excludes Serious Pathology

• Standard CT abdomen without arterial phase imaging misses mesenteric arterial stenosis and early ischemic changes 1
• The lack of arterial phase may lead to suboptimal evaluation of mesenteric arteries 1
• Every 6 hours of diagnostic delay doubles mortality in mesenteric ischemia, though this applies more to acute presentations 1

Do Not Delay CTA for Renal Function Concerns

• In a 15-year-old with normal labs, contrast administration is appropriate as the consequences of missed diagnosis far outweigh contrast risks 1
• CTA should be performed despite acute kidney injury concerns in adults, and this applies even more strongly to adolescents with normal renal function 1

Recognize Atypical Presentations

• Chronic mesenteric ischemia in adolescents may present without the typical atherosclerotic risk factors seen in elderly patients 1
• The migrating pain pattern suggests involvement of different vascular territories at different times 1

Biomarkers of Limited Utility

• D-dimer, lactate, and amylase are not sensitive or specific enough for chronic presentations and are more useful in acute mesenteric ischemia 1
• Intestinal fatty acid-binding protein (I-FABP) and other novel biomarkers lack sufficient evidence for routine clinical use 1

Symptomatic Management Considerations

• Avoid promotility agents like metoclopramide until vascular pathology is excluded, as increasing intestinal motility could theoretically worsen ischemia 5
• Pain management should be cautious with narcotics as they antagonize diagnostic evaluation and may mask progression 5