Mediastinal emphysema as the initial presentation of acute severe asthma

1. Images in pediatrics

A five year old boy was brought with complaints of recurrent bouts of cough for four days followed by a progressively increasing swelling of the neck with increasing respiratory distress and chest pain for one day. There was a family history of asthma in the first degree relative. At presentation, he was dyspneic with a respiratory rate of 38/min with room air oxygen saturation of 92%. He had extensive swelling of neck, which was extending to front of chest (Fig. 1). There was a palpable crepitus on examination of the swelling. Respiratory system examination revealed equal breath sounds bilaterally with expiratory wheeze. Chest radiograph revealed extensive sub-cutaneous emphysema of neck and pneumomediastinum (Fig. 2). Arterial blood gas was within normal limits. He was managed as a case of acute severe asthma with mediastinal emphysema and was treated with oxygen, continuous salbutamol nebulization, intermittent ipratropium nebulization and steroids. Within a few hours the respiratory distress subsided. He needed hospital stay and watchful monitoring for four days. At discharge, the visible swelling over the neck and chest wall had subsided.

Fig. 1.

Clinical photograph showing a swelling over the anterior aspect of neck extending till the chin.

Fig. 2.

A. Chest X-ray AP view showing air pockets in bilateral hilar region (white arrows) suggestive of pneumomediastinum. B. Chest X-ray AP view showing pockets of air along the subcutaneous plane of the chest wall, axilla (White arrow) and left arm suggestive of subcutaneous emphysema.

Pneumomediastinum refers to the presence of air in the mediastinum and also referred to as mediastinal emphysema [1]. It can be either primary (spontaneous), in which no obvious cause is found or secondary to known respiratory disorders like asthma and pneumonia [2]. Children with primary pneumomediastinum tend to be younger whereas children with secondary pneumomediastinum are usually older than six years of age with underlying asthma [2]. Asthmatic pneumomediastinum is characterized by cough, dyspnea, chest pain and expiratory wheezing. These symptoms are seen in more than 75% of children with asthmatic pneumomediastinum [1]. Rupture of over distended alveoli following violent cough episodes lead to tracking of air towards the hilum and neck producing pneumomediastinum [3]. It is a self limiting condition and resolves with the proper management of underlying condition. Hamman’s crunch is a valuable clinical sign that indicates the presence of subcutaneous emphysema, however it may be present in only 20% of the patients with pneumomediastinum and is diagnostic of the condition [4]. Frontal chest radiograph or a radiograph with lateral projection is diagnostic of pneumomediastinum and may depict the typical thymic sail sign or the ring sign which is nothing but free air surrounding the intra-mediastinal segment of right pulmonary artery [4]. Although it is a self limiting condition that resolves with the proper management of underlying disease process, it can be rarely complicated by tension pneumomediastinum or tension pneumothorax which may need urgent surgical decompression or intercostal tube drainage.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Informed consent

Signed informed consent for publication of the images obtained.

Declaration of competing interest

None stated.