Pediatric Pneumothorax Workup

Updated: Oct 16, 2019
  • Author: Andres Carrion, MD, FAAP; Chief Editor: Girish D Sharma, MD, FCCP, FAAP  more...
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Workup

Approach Considerations

A thorough history and physical examination usually lead to the diagnosis of a pneumothorax. Urgency, age, and cooperation of the child are some of the factors that should be taken under consideration when selecting imaging studies, because rapid worsening of the condition can occur before radiographs are obtained, especially in the setting of a tension pneumothorax. The size of the pneumothorax determines the rate of resolution and is a relative indication for active intervention. [1]

Chest radiography is the standard imaging for confirming a pneumothorax. Both CT scanning and thoracoscopy have proven useful for detecting blebs in case of recurrent or slow-to-resolve air leaks. Further investigation and pleurodesis should be considered in such cases.

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Chest Radiography

Pneumothorax is generally a clinical diagnosis that is confirmed with upright chest radiography. Anteroposterior (AP) and lateral views can reveal the presence of even small amounts of intrapleural air. Air in the pleural space that outlines the visceral pleura is a characteristic finding. Hyperlucency of vascular and lung markings on the affected side can be seen because of this air. Atelectasis may also be seen on the affected side due to compression by pleural air, and the mediastinum and trachea may shift away from the pneumothorax in the case of tension pneumothorax.

Lateral decubitus chest radiographs may be useful, especially in infants, as small pneumothoraces may be difficult to see on supine AP radiographs because the air accumulates anteriorly.

There is no standard method to measure the size of pneumothoraces in pediatric patients. The British Thoracic Society guidelines differentiate a large from a small pneumothorax by the presence of a visible rim of greater than 2 cm between the lung margin and the chest wall (at the level of the hilum). Per other sources, a pneumothorax is considered small if the distance between the lung apex and the ipsilateral dome of the thoracic cavity on an upright chest radiograph is less than 3 cm, and large if greater than 3 cm. [1]

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Laboratory Studies

Arterial blood gas (ABG) assessment should be obtained in patients with respiratory distress. Multiple abnormalities can be seen on ABG measurements in a patient with a pneumothorax. Hypoxemia frequently occurs due to ventilation-perfusion mismatch in the affected lung. The collapsed portion of the lung affected by pneumothorax is poorly ventilated but continues to receive adequate perfusion, which leads to hypoxemia. Patients may also have acute respiratory alkalosis on ABG assessment if they have significant pain, anxiety, and/or hypoxemia.

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Other Imaging Studies

A noncontrast chest CT scan is rarely required for diagnosis of a pneumothorax. CT scanning may be useful to further evaluate abnormalities seen on chest radiography, in detection of small blebs, or in distinguishing preexisting pulmonary pathologies. CT may also be useful in the diagnosis of secondary pneumothorax, as these patients have lower respiratory reserve and are more likely to require a procedure for even a small pneumothorax seen on imaging.

Ultrasonography has also been useful in detecting pneumothorax in adults, but similarly to chest radiography, it is difficult to estimate size of pneumothorax using ultrasonongraphy. The utility of ultrasonography in the pediatric population has not consistently been well described in the literature.

Transillumination of the thorax with a high-intensity fiberoptic probe may be helpful in guiding the diagnosis in newborns and infants.

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