Spontaneous pneumomediastinum

A male furniture removalist, 23 years of age, presented to his local doctor with neck swelling. He had an upper respiratory tract infection 2 weeks previously and was prescribed a course of oral antibiotics. He had returned to work 3 days before his presentation and described an episode of sudden onset, sharp, central chest pain while lifting a heavy object. The chest pain subsided within hours but he noticed a neck swelling at the onset of the pain, which has persisted. He pointed to a visible swelling on both sides of the posterior triangle of his neck. The swelling has persisted unchanged for the past 3 days. He smokes but has no other significant past medical history.