Persistent Shortness of Breath - Spontaneous Pneumothorax
There are a few barriers to the correct diagnosis and management of this presentation: a relatively well appearing child with a common complaint (chest pain), a possible alternative diagnosis (asthma-related symptoms), and family fears or expectations, which (although unfounded) may paradoxically steer the clinician away from the proper action.
His symptoms cannot yet be ascribed only to an asthma exacerbation (A), given no wheeze, normal tidal volume, no change with inhaled bronchodilators. Although there is an entity called cough-variant asthma (better called cough-dominant asthma - mostly in the context of atopy), his history of exacerbations fits the classical definition. Re-classifying his pattern of asthma to fit his ED presentation could be a major pitfall.
Performing an emergency chest tube thoracostomy on a relatively asymptomatic child with normal vital signs without confirmation of a pneumothorax is premature (C). This should be reconsidered if his status were to change. Given your completely reassuring physical exam in the clinical context, a chest radiograph is in order.
Sudden onset pleuritic chest pain could represent a spontaneous pneumothorax (SP), categorized as primary or secondary. A primary SP can be observed in otherwise healthy children or adults without lung disease. Risk factors for primary SP in children include growth spurt, smoking, and poor nutrition. Secondary SP is associated with parenchymal lung disease, such as asthma, cystic fibrosis, connective tissue disease, malignancy, foreign body aspiration, and congenital lobar emphysema (among others).
Diagnosis and management depend on the type (primary, recurrent primary, secondary, recurrent secondary), symptoms, and size of the pneumothorax; most guidelines are grounded in adult studies and extrapolated to pediatrics. The American College of Chest Physicians (ACCP) recommends tube thoracostomy for spontaneous pneumothorax >3 cm on a PA chest radiograph (which corresponds to >20% pneumothorax), as measured as measured from the chest wall apex to the ipsilateral apex of the lung parenchyma. (The British Thoracic Society has different definitions and management algorithms.)
Currently, there are no accepted criteria for pediatrics, as many formulae or “rules of thumb” for adults do not take into consideration the variability of the size of the pediatric thorax. A small retrospective study by Zganjer et al in 2010 reviewed 16 patients from 11 to 18 years old and determined that the pneumothorax was “small” if the rim of air surrounding the lung was less than 2 cm, ‘‘moderate’’ if the lung was 50% collapsed, and ‘‘complete’’ if there was no air within the lung. Clearly, larger prospective studies are needed to adopt this classification.
Our patient has a secondary pneumothorax (B) due to his asthma. Whether he receives a chest tube or observation will depend on his chest radiograph and continued stability (D). A chest CT may be considered for secondary spontaneous pneumothorax, if there are unknown but suspected blebs or bullae – there is less strength of evidence for primary SPs. The ACCP recommends admission for large or symptomatic primary pneumothoraces as well as admission for all secondary pneumothoraces, due to their higher risk of decompensation. Although they give no recommendations for pediatrics, this concept is readily extrapolated to children.
During the evaluation and decision process, patients with stable spontaneous pneumothoraces should have cardiopulmomary monitoring, be placed on high-flow oxygen to promote resorption, and staff should be made aware not to titrate oxygen down based on pulse oximetry.
Dotson K, Johnson LH. Pediatric Spontaneous Pneumothorax. Pediatr Emerg Care. 28(7):2012.