Pneumomediastinum complicating diabetic ketoacidosis.

A 24-year-old previously healthy man presented with a 3-week history of progressively intensifying symptoms of diabetes mellitus. He had become increasingly unwell during the night preceding his admission to hospital and had developed central pleuritic chest pains with nausea; he had vomited once. On admission, he was clinically dehydrated and acidotic with Kussmaul's respiration. A diagnosis of diabetic ketoacidosis was confirmed by laboratory tests (arterial pH 7.21; bicarbonate 11.6 mmol l-1; blood glucose 40.5 mmol l-1, and heavy ketonuria). Subcutaneous emphysema was palpable in the neck tissues and a chest X-ray revealed mediastinal emphysema. There was no clinical or radiological evidence of acute or chronic pulmonary disease and a barium swallow confirmed the integrity of the oesophagus. He made an uneventful recovery from the ketoacidosis with conventional therapy. The subcutaneous emphysema and pneumomediastinum had completely resolved at review 4 weeks later.