A 12-month-old female infant came to the clinic with persistent crying, scanty cough and respiratory distress of about 10 hours' duration. She associated two vomiting episodes, partial refusal of food and rhinorrhoea. His personal history included three previous episodes of bronchospasm. His mother had a family history of asthma.
Clinical examination revealed: weight 8.1 kg (P3), height 72 cm (P25), temperature 37.4°C, blood pressure 101/85 mm Hg, heart rate 148 beats per minute, respiratory rate 68 breaths per minute and oxygen saturation 90%. He had a good general appearance, was irritable and did not calm down in the mother's arms. He presented with shortness of breath, with subcostal and intercostal tugging. Respiratory auscultation showed good air entry with bilateral expiratory wheezing and elongated expiration. Cardiac auscultation was normal. The oropharynx was hyperemic, with abundant mucus in the cavum. Otoscopy showed bilateral tympanic hyperemia with preserved light reflex. The rest of the examination was normal.
Anteroposterior and lateral chest X-ray showed air trapping with the presence of anterocardiac air, a continuous diaphragm sign and minimal subcutaneous emphysema in the neck. A diagnosis of pneumomediastinum associated with bronchospasm was made and the patient was admitted to hospital. He was treated with oxygen through nasal goggles as needed, inhaled salbutamol and oral prednisolone. The clinical evolution was good, on the third day there were no signs or symptoms of respiratory distress, and the control chest X-ray showed a decrease in the size of the air in the mediastinum, so she was discharged. The sweat chloride test was normal.