In this paper two cases of spontaneous pneumomediastinum, occurring in a pa
tient with diabetic ketoacidosis and in a patient with bronchial asthma, ar
e presented. We describe the radiological findings, the differential diagno
sis and the important radiographic considerations in establishing the diagn
osis. In addition, we discuss the anatomical pathways and review the pathop
hysiological mechanisms responsible for the development of respiratory spon
taneous pneumomediastinum.