Epidural pneumatosis associated with spontaneous pneumomediastinum.

We read with much interest the article by S.J. Willing ( 1) that appeared in AJNR in 1991. The author states that epidural pneumatosis is commonly seen in trauma patients and that since computed tomography (CT) scans are seldom performed in spontaneous pneumomediastinum, a similar case has not been reported in the literature. Yoshimura, et al demonstrated the occurrence of epidural pneumatosis after strenuous karate exercise (2). We have encountered a case in which spontaneous pneumomediastinum and epidural pneumatosis occurred after prolonged vomiting. A 25-year-old man presented with a 2-day history of nausea and vomiting after ingestion of alcohol. During an episode of prolonged vomiting, he experienced substernal chest pain followed by coffee-ground emesis. On admission to the hospital , chest radiograph showed pneumomediastinum and subcutaneous emphysema in the neck. An esophogram was normal, and upper gastrointestinal endoscopy showed severe reflux esophagitis without an esophageal mucosal tear or fistula . A head CT, performed to exclude a brain neoplasm, showed air in the soft tissues of the upper neck. Additional CT images of the neck demonstrated a large amount of free air in the prevertebral fascia . On close examination, air was also seen in the epidural space (Fig . 1) and in the foramen transversarium. With conservative management, the patient's condition and the pneumomediastinum improved. The patient was discharged to home on the seventh day. The possible mechanism by which spontaneous pneumomediastinum occurs is sustained high bronchoalveolar pressure resulting in leakage of air into pulmonary perivascular interstitium. The air dissects into the mediastinum and along the paths of least resistance to the fascial planes of the neck. Air in the retropharyngeal space could then freely communicate with the epidural space via the neural foramina (Fig. 2). Severe vomiting or exercise may cause spontaneous pneumomediastinum and subsequent epidural pneumatosis.