This Chest Isn't Big Enough for the Both of Us: An Unusual Case of Congenital Unilateral Pulmonary Hypoplasia Diagnosed in an Adult

Abstract

INTRODUCTION: Unilateral pulmonary hypoplasia is a rare condition most often acquired in early childhood as a consequence of repeated inflammatory or infectious insults to the lungs, but may be congenital, as well. Congenital unilateral pulmonary hypoplasia is commonly associated with cardiac or vascular developmental abnormalities, and can occasionally be found in association with other anatomic aberrations such as congenital diaphragmatic hernia or bronchopulmonary sequestrations. This anomaly is most often detected in childhood and only a few congenital cases have been reported as an initial diagnosis in adults. We report a case of a woman who was diagnosed in her mid 40s with unilateral pulmonary hypoplasia associated with right pulmonary vein atresia. CASE PRESENTATION: A 45 year-old female, who had immigrated to the U.S. from Mexico several years ago, and without significant past medical history, presented to her primary care provider in 2007 with a complaint of chronic dyspnea with heavy exertion (NYHA class II), but otherwise asymptomatic. She was found to have an abnormal chest X-ray but no further work-up was done until September 2009, when she re-presented with persistent dyspnea on exertion. She was a lifelong non-smoker, and was working as a custodian at a local school. She was referred to pulmonary clinic after a follow up CT thorax was also found to be abnormal. The patient recalled a single episode of “pneumonia” in childhood, and was told in the past that she might have “lung problems”. Review of her initial CXR from 2007 showed opacification of the right hemithorax, loss of the cardiac silhouette, and mediastinal shift to the right. CT angiogram of the thorax done in 2009 revealed a profoundly hypoplastic right lung with a hypoplastic right pulmonary artery and likely congenital absence of the right pulmonary veins. Pulmonary function testing was consistent with mild restriction, a preserved DLCO, and absence of resting room air hypoxia. No active intervention was considered for her other than supportive measures including annual prophylactic vaccinations and periodic follow up in pulmonary clinic. DISCUSSIONS: Only 33 cases of unilateral pulmonary hypoplasia in association with pulmonary vein atresia have been reported, and of those, only 8 cases were diagnosed as adults. Most patients are identified early in life because of dyspnea, recurrent lower respiratory tract infections, hemoptysis, or pulmonary hypertension. In adulthood, most patients present with dyspnea on exertion. The diagnosis is suggested by plain films, but CT imaging is required for confirmation. Pulmonary angiography whether by CT, MRI, or conventional angiography is needed to elucidate the vascular anatomy if a congenital case is suspected. The diagnosis may be elusive in an adult patient due to poor access to care (as in this case), or minimal symptoms. Our patient's symptoms do not interfere with her activities, and we will therefore manage her conservatively for now. There is no robust data in the literature available on the management of the adult patient with this condition. The pediatric literature suggests referral for pneumonectomy of the hypoplastic lung if recurrent bronchopulmonary infections or refractory hemoptysis develop. CONCLUSION: Congenital unilateral pulmonary hypoplasia associated with pulmonary vein atresia is rarely diagnosed in adulthood. Management options such as pneumonectomy or vascular surgery have been described for pediatric cases, but data in adult patients is scarce.