Four patients with severe diabetic ketoacidosis in coma had proven mediastinal and subcutaneous emphysema and, in each patient, the probable cause was emesis. There was no evidence of esophageal laceration or rupture. Recovery was complete without surgical intervention or other specific therapy for the emphysema.
Beigelman PM, Miller LV, Martin HE. Mediastinal and Subcutaneous Emphysema in Diabetic Coma With VomitingReport of Four Cases. JAMA. 1969;208(12):2315-2318. doi:10.1001/jama.1969.03160120039009