A narrative review of primary spontaneous pneumomediastinum: a poorly understood and resource-intensive problem.

Primary spontaneous pneumomediastinum (PSPM) is a benign self-limited condition that can be difficult to discriminate from esophageal perforation. This may trigger costly work-up, transfers and hospital admissions. To better understand this diagnostic dilemma and current management, we undertook the most comprehensive and up to date review of PSPM. The PubMed database was searched using the MeSH term "Mediastinal Emphysema"[Mesh], to identify randomized controlled trials, meta-analyses and case series (including 10 or more patients) relevant to the clinical presentation and management of patients with PSPM. There were no relevant randomized controlled trials or meta-analyses. Nineteen case series met our criteria, including a total of 535 patients. The average mean age was 23 years with a 3:1 male predominance. Chest pain was the most common symptom, found in 70.9% of the patients. Dyspnea and neck pain were the second and third most common symptoms, found in 43.4% and 32% of the patients, respectively. Subcutaneous emphysema was the most common sign (54.2%). Common histories included smoking (29.6%), cough (27.7%), asthma (25.9%), physical exertion (21.1%) and recent retching or emesis (13%). Nearly all patients (96.9%) underwent chest X-ray (CXR). Other diagnostic studies included computed tomography (65%) and esophagram (35.6%). Invasive studies were common, with 13% of patients undergoing esophagogastroduodenoscopy and 14.6% undergoing bronchoscopy. The rate of hospital admission was 86.5%, with an average length of stay of 4.4 days. No deaths were reported. Notably, we identified a dearth of information regarding the vitals, laboratory values and imaging findings specific to patients presenting with PSPM. We conclude that PSPM is a benign clinical entity that continues to present a resource-intensive diagnostic challenge and that data on the vitals, labs, and imaging findings specific to PSPM patients is scant. An improved understanding of these factors may lead to more efficient diagnosis and management of these patients.