Pneumomediastinum and Subcutaneous Emphysema Complicating Acute Exacerbation of Bronchial Asthma

Introduction Pneumomediastinum otherwise known as mediastinal emphysema refers to the presence of air within the mediastinum while subcutaneous emphysema refers to the presence of air in the subcutaneous tissue and this may involve the face, neck or trunk [1]. The term, pneumomediastinum, was introduced into medical literature by Hamman in 1939[2]. Both conditions are relatively uncommon but important complications of bronchial asthma. The first definitive case of asthma complicated by subcutaneous emphysema was reported in a child in 1850 even though Laennec, as early as 1819, had recognized symptoms and signs of subcutaneous emphysema [3]. Extravasations of air in extra-pulmonary tissues may also manifest as pneumopericardium or pneumothorax and may as well complicate, apart from asthma, perforation or rupture of oesophagus (Boerhaaves syndrome), rupture of trachea or main bronchi, or conditions resulting in raised intrathoracic pressure [valsalva manouvre as in vaginal delivery, weight lifting, vomiting, strenuous exercise], following paraquat intoxication, dental procedures, blunt or penetrating trauma or soft tissue infection. It may also complicate gastrointestinal instrumentation such as endoscopy, colonoscopy and laparoscopic surgery [4].