(200) Cor Pulmonale Secondary to Abernethy Malformation Type 1b

Introduction: Abernethy malformation (AM) type 1b is a rare congenital extrahepatic portosystemic shunt where portomesenteric blood drains directly into systemic circulation, often associated with other congenital malformations. Pulmonary hypertension, though a rare complication of AM, is life-threatening and requires prompt and effective management. This case describes one of the few cases reported in which AM is accompanied by severe pulmonary hypertension.

Description: A 3-year-old female with past medical history of AM type 1b, chronic cyanosis, and hepatic dysfunction was admitted to the Pediatric Intensive Care Unit (PICU) due to increased cyanosis, respiratory difficulty, and abdominal pain. Further evaluation revealed thrombocytopenia and increased pulmonary markings on chest X Ray, suggesting a pneumonic process. Additionally, lab results showed acidosis, hyperbilirubinemia, elevated AST, and prolonged prothrombin time (PT), prompting her PICU admission. Past medical history is further remarkable for pulmonary HTN, oxygen dependence, polysplenia, and intestinal malrotation.
CT scans revealed that the mesenteric and splenic veins form a short extrahepatic portal vein that drains into the left renal vein, then the IVC, with no portal vein in the liver. The echocardiogram revealed right ventricle (RV) failure. The AM likely contributed to fluid overload, pulmonary hypertension, and RV failure, which were treated with diuretics, milrinone infusion, a high-flow nasal cannula, and inhaled nitric oxide. Thrombocytopenia, prolonged PT, hypofibrinogenemia, and a high reticulocyte count without anemia were attributed to sequestration by multiple spleens, although anatomical anomaly involvement was not ruled out. Vitamin K was used to treat prolonged PT and hypofibrinogenemia. Elevated liver enzymes and bilirubin were most likely due to liver involvement secondary to heart failure. The patient recovered and hepatic dysfunction improved. She was discharged home on oxygen, diuretics, and sildenafil.

Discussion: This case highlights the intricacy of AM type 1b when complicated by pulmonary hypertension. It emphasizes the need for multidisciplinary care management and close follow-up to avoid this life-threatening complication, especially when surgical correction of the shunt may not be possible.