Continuous diaphragm sign as an initial presentation in a case of bronchial asthma

The chest radiograph of a 13-year-old boy who presented with acute onset cough with increasing breathlessness associated with wheezing revealed a rare and intriguing finding of a continuous diaphragm with a clear space between the heart and inferior border of the heart (“continuous diaphragm sign”), along with an area of lucency in the subcutaneous tissue of the neck and chest wall [Figure 1]. He had multiple episodes of acute attacks of asthma in the past, which used to be relieved after nebulization with a shorter-acting Beta-2 agonist. He also denied any history of foreign body aspiration and trauma. On local examination, he was noted to have facial puffiness, palpable crepitus over the neck and upper anterior chest region bilaterally, and polyphonic rhonchi on chest auscultation. His vital signs were a respiratory rate of 36/minute, pulse rate of 120/minute, blood pressure of 120/80 mmHg, and oxygen saturation of 91% in room air.Figure 1: Chest radiograph showing a clear space between the heart and inferior border of the heart, along with an area of lucency in the subcutaneous tissue of the neck and chest wall, suggestive of Pneumomediastinum with subcutaneous emphysema.Question. What is your diagnosis? Answer: Bronchial asthma (acute exacerbation) with pneumomediastinum and subcutaneous emphysema. Discussion Incidence of pneumomediastinum (PM) is rare in children. The most common triggering factors include underlying respiratory disease with intense cough, foreign body aspiration, gastrointestinal disorders with excessive vomiting, strenuous exercise, seizures, and diabetic ketoacidosis.[1] PM is diagnosed mainly clinically and confirmed by chest radiograph.[2] In asthma exacerbations, pneumothorax and pneumomediastinum develop because the obstruction in the airways leads to air-trapping, with an abrupt increase in intra-alveolar pressure (known as the Macklin effect) followed by barotrauma of the distal airways, with subsequent alveolar rupture.[3] Treatment is primarily supportive with oxygen therapy and cough suppressants (as in our case), along with treating the underlying disorder like nebulization with bronchodilators and systemic steroids as in our case. It is usually self-limiting.[4] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.