Pneumomediastinum seen on chest x-ray after blunt trauma always attracts attention. Possible sources may be related to very serious injuries to the aerodigestive tract. When seen in children, it causes considerable anxiety, which usually results in a very detailed workup and lots of imaging.

Children’s Hospital of Boston looked at the National Trauma Data Bank, as well as 19 years worth of their own records to see whether all the attention is justified. They found 193 patients in the NTDB that met their criteria, and most were in their late teens and had other significant injuries. Of the 17 with isolated pneumomediastinum, none had any other significant injury.

When reviewing their own patient records, they found 18 with pneumomediastinum, and all but one was seen on plain chest x-ray. Most were transferred to the hospital from referring centers, and had been involved in sports-related mechanisms. Half had undergone studies in addition to a chest x-ray before transfer. All were discharged home without any surgical interventions.

Bottom line: Pneumomediastinum is rare in children, even older ones. If associated with significant aerodigestive injuries, it was never an isolated occurrence. Other signs or symptoms were present. Pediatric patients presenting with an isolated pneumomediastinum can be safely observed, using chest x-ray and physical examination alone. More sophisticated studies (CT, barium studies) are not indicated.

Reference: Clinical outcomes and diagnostic imaging of pediatric patients with pneumomediastinum secondary to blunt trauma  to the chest. J Trauma, epub, 2011.