Spontaneous Pneumomediastinum: A Narrative Review Offering a New Perspective on Its Definition and Classification.

Pneumomediastinum is the abnormal presence of air in the mediastinum. It is typically classified into two types: spontaneous (occurring without any underlying lung disease) and secondary (resulting from various conditions, including trauma). The most common clinical symptoms include retrosternal chest pain, difficulty breathing, subcutaneous emphysema in the neck or chest, and, in some cases, Hamman's sign, which involves crackles that occur in sync with the heartbeat. This study has two main objectives: first, to assess whether there is consistency between the definition of spontaneous pneumomediastinum presented by the authors and the description provided in their articles, and second, to evaluate whether the classification of spontaneous pneumomediastinum aligns with its definition. We conducted a literature search using PubMed, Google Scholar, and the Springer Journal Archive databases.