PC1191: Obstructive Shock in Extensive Subcutaneous Emphysema from Minimal Trauma: A Case Report

Introduction: Subcutaneous emphysema (SE) is a condition in which air accumulates under the skin. Several causes include trauma, infection or alveolar rupture. Rapidly progressing subcutaneous emphysema after minimal trauma is rare.

Case Description: A 17-year-old male presents to the emergency department (ED) after worsening right calf swelling and redness from a self-inflicted stab wound using a glitter pen seven hours prior to arrival. The patient also reported pain all throughout the right side of his body and difficulty breathing. On examination he was alert, oriented, and in no acute distress with a temperature of 39 degrees Celsius, heart rate of 125 bpm and blood pressure 84/56 mmHg. Respiratory rate was 22 breaths per min with an oxygen saturation of 100% on room air. His clinical exam revealed an obvious puncture wound in the anterior compartment of the right lower leg with surrounding erythema, tenderness and marked crepitus along the entire length of the right lower extremity, extending up along the hip into the abdomen, chest and shoulder region on the right side. The case was emergently referred to the on-call surgical team and he was immediately taken to the operating room for exploration and decompression. Intra-operative findings included extensive subcutaneous emphysema and healthy viable tissue with a moderate amount of blue ink in the subcutaneous tissues. He was subsequently admitted to the Surgical Intensive Care Unit (ICU) where he had an unremarkable hospital course and discharged on post-op day 4 with a diagnosis of traumatic SE.

Discussion: Rapidly progressing SE after minimal trauma is a rare condition. Several case reports describe traumatic SE due to migration of a metal fracture fixation device, wound irrigation with hydrogen peroxide, generation of gas following wound contamination with chemicals, and accidental or deliberate injection of air directly into the tissues. In these cases, it is postulated that movement and continued use of the limb leads to a ‘one-way valve’ mechanism leading to air trapping into the underlying soft tissues. We tried to identify the potential cause for rapid progression of SE in our case. We hypothesize that the combination of a trivial injury and gas formation from contact of metallic ink enhanced accumulation of the generated gas that is subsequently trapped into the soft tissues.

Conclusion: Differentiation of infectious from non-infectious causes of SE is imperative. Traumatic SE should be suspected in cases where there is a clean appearance of the wound and a short delay between injury and development of palpable crepitus. Management of SE is mostly conservative, however in unstable patients may require surgical treatment.