Subcutaneous emphysema is usually considered to be a surgical emergency and should be considered gas gangrene or necrotising fasciitis until proven otherwise. In rare circumstances, however, patients may present with benign subcutaneous emphysema, which is non-infectious, self-limiting and does not require surgery.
Benign subcutaneous emphysema of the upper limb is a rare entity that has been reported less than 20 times in the English literature. First, we present the current literature on benign subcutaneous emphysema. Most presentations have been attributed to a laceration over the olecranon that act as a ball-valve mechanism, pushing air into the soft tissue when the patient moves their elbow.(1) Other reported causes include blunt trauma, insect bite, air rifle shooting, iatrogenic from intravenous cannulation and elbow arthroscopy and accidental puncture with a pneumatic tyre pump. (2-7)
Second, we present the case of a 51 year old man who presented with a right elbow laceration from a hedge trimmer and rapidly increasing swelling to his upper limb. He had subcutaneous emphysema of his volar compartment of arm extending to shoulder, as well as of his dorsal compartment of his forearm, extending to the dorsum of his hand. He was initially managed conservatively with intravenous antibiotics and elevation. The day after he presented, he had an MRI which was reported as necrotising fasciitis with widespread soft tissue gas. He underwent surgical exploration which showed gas bubbles in the fascia but no signs of infection and healthy muscle. Our case illustrates the diagnostic dilemma associated with benign subcutaneous emphysema of the upper limb. It is also the first case to show MRI findings associated with benign subcutaneous emphysema.