SESSION TITLE: Imaging Student/Resident Case Report Posters
SESSION TYPE: Student/Resident Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: Unilateral agenesis of the pulmonary artery (UAPA) is a rare developmental anomaly due to failure of a connection between the sixth aortic arch and the pulmonary trunk. It is rarely diagnosed in adults, and is mostly seen in the pediatric population.
CASE PRESENTATION: We present a case of a 77 year old male who presented to the ER with 3 days of substernal chest pain at rest. Review of systems was significant for dyspnea on exertion, pleuritic chest pain, and palpitations. Past medical history only included hypertension. His vital signs were within normal limits and he appeared comfortable without any significant exam findings. Further work-up showed negative cardiac enzymes and an unremarkable EKG. To rule out pulmonary embolus (PE), a CT chest angiogram was performed. There was no evidence of PE, however, the scan showed agenesis of the left pulmonary artery with multiple collateral bronchial vessels supplying the left lung as well as a dilated main pulmonary artery. A subsequent V/Q scan also elicited agenesis of the left pulmonary artery with no subsegmental PE. The patient’s pulmonary function test was unremarkable.
DISCUSSION: Lung development begins early in gestation when outpouching from the primitive foregut begins to produce lung buds. This process continues until the 5th week of gestation. An insult after the 4th week that disrupts this process and cell migration to the pharyngeal arches can lead to underdevelopment of lung tissue or agenesis of pulmonary arteries. Today most cases of UAPA are diagnosed early due to advances in prenatal care and imaging. Prior to this, suspicion for UAPA occurred in unexpected pregnancy loss and in infants with respiratory distress. Our patient’s relative good health never required chest imaging or pulmonary studies prior to his emergency room visit, thus this diagnosis of was cloaked until late in adulthood. Left pulmonary agenesis, as seen in our case, is the most common form, accounting for up to 70% of reported cases. This is likely due to the fact that right sided pulmonary anomalies are often part of an association or broader congenital syndrome. Due to the onset of pulmonary symptoms, or as a result of non-pulmonary manifestations of an associated syndrome, a majority of patients with UAPA die in infancy. Rarely do patients remain asymptomatic until adulthood. The co-existent anomalies, which were absent in our patient, could be the reason why our patient went undiagnosed for so long. His extensive collateral circulation seen on CTPA, likely allowed for him to remain asymptomatic.
CONCLUSIONS: Many patients without any significant medical co-morbidities, as our case described, may go undiagnosed with UAPA until later in life, if at all.
Reference #1: Reading, D Umesh, O et al. Unilateral absence of a pulmonary artery: a rare disorder with variable presentation. Proc (Bayl Univ Med Cent). Apr 2012; 25(2): 115-118.
DISCLOSURE: The following authors have nothing to disclose: Craig Grossman, David Wisa, Khalid Gafoor, Daniel Zapata, Maciej Walczyszyn, Bushra Mina
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