A 9 year-old girl with global developmental delay as a result of past meningitis presented to the emergency department by parent transport with complaints of fussiness. She had mild cough and increased oral secretions without history of fever or vomiting. Parents stated that she has not been acting like herself, which was attributed to constipation.
Physical exam was notable for a temperature of 34.0 degrees Celsius, HR 96, BP 107/67, RR 30, O2 97% breathing room air. She had significant oral secretions requiring suctioning throughout the exam but the oropharynx was normal appearing. Heart was with a regular rate and rhythm without murmur. Breath sounds were markedly diminished over the left lung field without focal crackles or accessory muscle use. Abdominal examination was normal.
Figure 1 Figure 2
Chest radiograph was obtained and revealed complete whiteout of the left lung (Figure 1). Point-of-care ultrasound was then performed, which showed a large pleural effusion with septations consistent with a complex effusion (Clip 1 and Figure 2).
Role of Lung Ultrasound for Evaluation of “Whiteout” Lung
The primary etiologies of “whiteout” lung include pneumonia, atelectasis, pleural effusion, empyema, or tumor.1 While chest radiograph remains the initial test of choice, lung ultrasound represents a useful adjunct to differentiate consolidation from effusion, and to further define pathology. Further, lung ultrasound can facilitate management decisions, such as the need for advanced imaging (ie, CT) or surgical consultation, or guidance of thoracentesis. In our case, point-of-care ultrasound revealed a large pleural effusion with findings suggestive of loculation. This resulted in expedited chest CT and prompt consultation with pediatric surgery for consideration of VATS vs administration of tPA/Pulmozyme administration through a chest tube.
Answers to Questions
1. What is the role of lung ultrasound in the pediatric patient?
Point-of-care lung ultrasound is ideal for pediatric patients given the lack of ionizing radiation. Indications have primarily focused on identification of pneumonia . Test characteristics for identification of pneumonia have been favorable, with a reported sensitivity and specificity of 86-87% and 89-95%, respectively.2,3 For consolidations measuring greater than 1 cm, the specificity increases up to 97%.2
Literature regarding other indications in the pediatric patient, including identification of pneumothorax or pleural effusions, is generally less robust compared to adults.4,5 Small prospective studies in neonates and children suggest that lung ultrasound has favorable test characteristics for identification of pneumothorax and may outperform clinical evaluation.6,7
More recent investigations in children have focused on identification of findings suggestive of viral pathology, such as bronchiolitis.8,9 These studies suggest that children less than 2 years of age presenting with wheeze/bronchiolitis symptoms are likely to display B lines, whereas children with true asthma often do not. The presence of B lines was also associated with a lack of atopy, further suggesting that B lines may be present with viral-induced wheezing.8
2. What sonographic features are found with pleural effusions, and which features suggest simple vs. complex pleural effusion?
Pleural effusions typically appear as an anechoic space between the visceral and parietal pleura. Anechoic fluid collections often represent transudative effusions, whereas heterogeneous/hyperechoic fluid collections suggest an exudative effusion.10 Visualization of internal echos or septa, which were noted in our patient, are also highly suggestive of an exudative effusion.11,12 Other findings include the sinusoid sign, which represents the interpleural variation with the respiratory cycle,13 and the jellyfish sign, which represents the compressed lung floating within the effusion.10
3. What are common pitfalls encountered with lung ultrasound?
Pericardial effusions can be easily misidentified as pleural effusions. The descending thoracic aorta is a key landmark to help differentiate the location of effusion, which can be identified by adjusting depth where appropriate. Pleural effusions are posterior to the descending aorta, whereas pericardial effusions are anterior to this structure.14 Another common pitfall is misidentification of the combination of spleen and adjacent gastric air as a consolidation with air bronchogram.2 In younger children, the thymus may also be confused for consolidation.2