SESSION TITLE: Miscellaneous Cases V
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 07:30 AM - 09:00 AM
INTRODUCTION: Congenital pulmonary airway malformations (CPAM) are rare developmental anomalies. We present an adult male who developed mediastinal tension due to a CPAM.
CASE PRESENTATION: A 25-year-old male presented with a one-day history of chest pain and dyspnea. His past medical history was significant for: recurrent chest infections, a six pack-year smoking history, and alcohol abuse. He took no regular medications. He had no previous chest imaging. His initially mild chest discomfort had progressed to become constant and severe. He developed dyspnea at rest. He had no infectious symptoms and no recent travel. Upon presentation to the ED his vital signs included: HR 100, BP 142/69, SaO2 94%. Examination showed decreased breath sounds to the left and distended neck veins. The initial chest x-ray (Figure 1) showed mediastinal shift and a hyperlucent left lung. Tension pneumothorax was the initial diagnosis and a thoracostomy tube was placed without clinical or radiologic change. A CT Chest demonstrated a hyperinflated left lower lobe with subsequent atelectasis of the left upper lobe and rightward shift of the mediastinum (Figure 2). The patient was admitted for a left lower lobectomy. Extrinsic compression of the left lower lobe bronchus was shown on bronchoscopy. Pathological examination confirmed the diagnosis of Type 1 CPAM. After an uncomplicated recovery his chest x-ray revealed aeration of the left upper lobe and resolution of the mediastinal tension.
DISCUSSION: A small number of CPAM cases will present outside the perinatal period. Reported clinical manifestations in adulthood include: recurrent infections, pneumothorax, hemoptysis, dyspnea, and incidental imaging abnormalities.  To our knowledge there are only two cases of CPAM-associated mediastinal tension reported. The first occurred in a 5-year-old boy with no clear inciting triggers.  The second occurred in a 26-year-old female who became symptomatic during air travel.  Both were managed with lobectomy. In the case presented above the patient had no clear inciting event. Our hypothesis is that a subclinical event resulted in a one-way check-valve phenomenon with progressive hyperinflation of the left lower lobe CPAM.
CONCLUSIONS: This case highlights the need to keep a broad differential when initial therapeutic attempts do not produce the desired result. CPAM hyperinflation should be considered in a younger patient with mediastinal shift and a chest x-ray showing lung markings in the area of presumed pneumothorax.
Reference #1: Herrero Y, Pinilla I, Torres I, Nistal M, Pardo M, and Gomez N. Cystic adenomatoid malformation of the lung presenting in adulthood. Annals of Thoracic Surgery. 2005;79:326-329.
Reference #2: Boon D, Llewellyn T, and Rushton P. A strange case of a tension pneumothorax. Emergency Medicine Journal. 2002;19:470-471.
Reference #3: Madan K, Vishwanath G, and Singh N. In-flight spontaneous pneumothorax: congenital cystic adenomatoid malformation of the lung. Respiration. 2012;83:554-558.
DISCLOSURE: The following authors have nothing to disclose: Daniel Miller, Sean Grondin, Michael Roman
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