PC1189: Two Roads Diverged in a Lung, and I-- i Took the Shunt Less Traveled By

Introduction: Hepatopulmonary syndrome is a complication of chronic liver disease that leads to intrapulmonary vascular dilation and malformations that result in anatomic shunting and ventilation-perfusion mismatch – ultimately leading to hypoxemia. This complication is more commonly thought of in children with stigmata of advanced liver failure such as encephalopathy or ascites. We present the case of a child admitted for adrenal crisis and status asthmaticus, who was found to have hepatopulmonary syndrome through work-up for persistent hypoxemia.

Case Description: A 15-year-old boy with history of resected oncocytoma with secondary pan-hypopituitarism, type 2 diabetes, obesity, and asthma presented in adrenal crisis secondary to dehydration and Rhinovirus positive viral illness. He was also noted on presentation to have acute hypoxemic respiratory failure requiring supplemental oxygen and was initially treated for status asthmaticus. After initiation of stress dose steroids and bronchodilator therapy, and overall clinical improvement, his hypoxemia persisted. Desaturations persisted at rest and worsened with exertion and when sitting upright. Workup included normal chest x-ray, CT Chest Angiogram which did not show pulmonary embolism or parenchymal lung disease, and normal trans-thoracic Echo. Lab testing was notable for mild transaminitis, mild hyperbilirubinemia, thrombocytopenia, and mildly elevated INR. Due to concern for chronic liver disease and anatomic shunting, echocardiogram with bubble study was performed and was positive. ABG was obtained and concerning for severe arterial hypoxemia. Further chart review revealed history of elevated transaminases, presumed due to NASH, however with most recent Fibroscan demonstrating significantly elevated liver stiffness of 75 kPa.

Cardiac catheterization was performed, and he was found to have diffuse pulmonary arteriovenous malformations. Liver biopsy demonstrated stage 4 cirrhosis. Based on his biopsy, catheterization results, and ABG, he was diagnosed with hepatopulmonary syndrome and listed for liver transplantation.

Discussion: Hepatopulmonary syndrome is diagnosed with arterial blood gas showing elevated A-a gradient and hypoxemia, demonstration of intra-pulmonary shunting on imaging, or with cardiac catheterization showing pulmonary arteriovenous malformations in patients with hepatic dysfunction. It is typically associated with patients with fulminant hepatic failure. This case demonstrates that it may present in otherwise well appearing children with chronic, non-fulminant liver disease. Some data suggests pan-hypopituitarism, and its associated metabolic syndrome, may lead to rapidly progressive non-alcoholic steatohepatitis. Therefore, these patients should be closely monitored for signs of progressive liver dysfunction and cirrhosis. If diagnosed, the only true treatment of hepatopulmonary syndrome is liver transplant, which often leads to the resolution of pulmonary arteriovenous malformations.

Conclusion: This case highlights the importance of maintaining a broad differential in the work-up of persistent hypoxemia, and the importance of close monitoring of liver disease progression in patients with hepatic dysfunction secondary to pan-hypopituitarism.