Expanding upon the Unilateral Hyperlucent Hemithorax in Children

Abstract

Unilateral hyperlucent hemithorax is a common pediatric chest radiographic finding that may also be seen at computed tomography. It may result from congenital or acquired conditions involving the pulmonary parenchyma, airway, pulmonary vasculature, pleural space, and chest wall, as well as from technical factors such as patient rotation. Unilateral hyperlucent hemithorax has a broad differential diagnosis that includes unilateral emphysematous or bullous disease, pneumatocele, foreign body aspiration, Swyer-James syndrome, congenital lobar emphysema, endobronchial mass, unilateral pulmonary agenesis, proximal interruption of the pulmonary artery, scimitar syndrome, diaphragmatic hernia, and Poland syndrome. Although certain causes of unilateral hyperlucent hemithorax are clinically significant and potentially life threatening, others are of minimal or no clinical significance. When evaluating a patient with this finding, it is important to establish whether the apparent unilateral hyperlucent hemithorax is truly too lucent (hypoattenuating) or if the contralateral hemithorax is too opaque (hyperattenuating). It is imperative that radiologists be aware of the various causes of unilateral hyperlucent hemithorax so that they may diagnose the underlying condition and appropriately guide patient management.

Cases Diagnosed with Swyer James Macleod Syndrome in Adulthood

“…Differential diagnosis of unilateral hyperlucent lung includes parenchymal lung diseases (unilateral emphysema or bullous lung), airway diseases (foreign body aspiration, endobronchial mass, congenital lobar emphysema, bronchial atresia), vascular diseases (pulmonary agenesis or hypoplasia, scimitar syndrome, unilateral central pulmonary embolus), pleural diseases (pneumothorax), and chest wall diseases (Poland syndrome, scoliosis) [13]. In a series comprising 40 patients that were investigated for unilateral hyperlucent lung, prevalence of SJMS was 45%, local emphysema was 20%, congenital pulmonary artery hypoplasia was 10%, pulmonary embolus was 10%, bronchial carcinoma was 7.5%, radiotherapy sequel was 5%, and endobronchial tumour was 2.5% [14].…”

Inadvertent chest tube insertion in congenital cystic adenomatoid malformation and congenital lobar emphysema-highlighting an important problem

“…The prominent differentials for cystic lucent chest lesion on chest radiograph in infants and young children (under 3 years of age) with respiratory distress are post-infective pneumatocele, pneumothorax, congenital diaphragmatic hernia (CDH), congenital cystic adenomatoid malformation (CCAM), congenital lobar emphysema (CLE), pulmonary sequestration, bronchogenic cyst, and bullous lung disease. [123] Congenital cystic lung lesions are relatively rare in incidence and have a varied clinical presentation. [4] Majority of the patients usually present in infancy or within the first 3 years of life.…”

Vanishing lung syndrome

“…1 Abnormalities of the thoracic wall and soft tissue are the most common causes. Pneumothorax, emphysema, large bullae, airway obstruction, contralateral pleural effusion and radiographic artifact can also give rise to increased transradiancy of the lung.…”