A 16-year boy, on ART and AKT since 2 months, presented with body ache since 1 day. On examination he is malnourished, vital stable. He has subcutaneous emphysema on both side of back from neck to lumbar region and on the anterior chest wall.

Clinically no pneumothorax. What could be the source of air for such extensive subcutaneous emphysema? Give your suggestions.