A term newborn born to a mother with meconium-stained amniotic fluid presents with tachypnea (RR 68/min), intercostal retractions, and grunting within 2 hours of birth. Oxygen saturation is 88% on room air. Which investigation is most appropriate to confirm the diagnosis of meconium aspiration syndrome?

Explanation

## Diagnosis of Meconium Aspiration Syndrome ### Role of Chest X-Ray **Key Point:** Chest X-ray is the gold standard imaging investigation for confirming meconium aspiration syndrome (MAS) and assessing severity. ### Classic Radiological Findings The chest X-ray in MAS typically shows: 1. **Hyperinflation** — bilateral hyperinflation with flattened diaphragms 2. **Patchy infiltrates** — irregular, asymmetric opacities ("ball-in-glove" or "meconium plug" appearance) 3. **Atelectasis** — areas of collapse alternating with hyperinflation 4. **Air bronchograms** — may be present 5. **Pneumothorax/Pneumomediastinum** — in severe cases (barotrauma) ### Why Chest X-Ray is Diagnostic - **Confirms aspiration** — meconium particles in airways cause the characteristic pattern - **Assesses severity** — extent of infiltration guides management intensity - **Detects complications** — air leak syndromes (pneumothorax, pneumomediastinum) - **Baseline for monitoring** — serial films track resolution or deterioration **Clinical Pearl:** The combination of **perinatal meconium exposure + respiratory distress + characteristic chest X-ray findings** = diagnostic triad for MAS. Clinical diagnosis alone is insufficient; imaging confirmation is essential for severity grading and prognostication. **High-Yield:** MAS severity correlates with chest X-ray findings: - **Mild:** hyperinflation only - **Moderate:** hyperinflation + patchy infiltrates - **Severe:** widespread infiltrates + air leak syndromes [cite:Nelson Textbook of Pediatrics 21e Ch 102]