Nelson Textbook of Pediatrics 22nd Edition | Air in the mediastinum due to alveolar rupture (Macklin effect) → air dissects along perivascular sheaths into mediastinum. Causes: asthma exacerbation, Valsalva (vomiting, coughing, weightlifting, singing), trauma, mechanical ventilation, Boerhaave syndrome (esophageal rupture), diabetic ketoacidosis, inhalational drug use. Clinical: chest pain (retrosternal), dyspnea, subcutaneous emphysema (crepitus in neck/chest), Hamman sign (mediastinal crunch on auscultation). CXR: air outlining mediastinal structures (spinnaker sail sign - thymus lifted, ring sign around pulmonary artery, continuous diaphragm sign, subcutaneous emphysema). Treatment: usually self-limited, supportive care, avoid Valsalva. Rarely requires drainage (mediastinal drain). Differentiate from pneumothorax (no mediastinal shift).
🌐 paeds.online — Pakistan's Pediatric Platform| Type | Management |
|---|---|
| Spontaneous (asthma, Valsalva) | Observation, supportive care, treat underlying asthma, avoid Valsalva. Usually resolves in days. |
| Traumatic (esophageal rupture, Boerhaave) | Surgical repair, antibiotics, mediastinal drainage |
| Mechanical ventilation-related | Reduce airway pressures, treat pneumomediastinum, chest tube if pneumothorax |
| Severe (tension physiology) | Mediastinal drain, treat underlying cause |