An Unusual Case of Cyanosis in a Young Boy

Abstract

Question: A 13-year-old boy presented with a 2.5-year history of dyspnea and fatigue and detected to have cyanosis over the past 6 months. He did not have any history of palpitations, syncope, cough, wheezing, or recurrent chest infections. He was the elder of 2 siblings, born out of a nonconsanguineous marriage with a normal, uncomplicated antenatal and perinatal history. His developmental history and performance at school were normal. His clinical examination revealed normal anthropometric parameters as per his age, cyanosis at rest, and grade III clubbing of fingers; the rest of his systemic examination including cardiovascular, pulmonary, neurologic, and abdominal examination was normal. Arterial blood gas analysis revealed type 1 respiratory failure, mild respiratory alkalosis, and severe hypoxemia (pH, 7.46; PO2 on room air, 49 mmHg; PCO2, 32.9 mmHg; HCO3, 23.1 mmol/L; SpO2, 88%). Chest xray was normal. Air contrast-enhanced transthoracic echocardiography revealed right-to-left shunting evident by the appearance of air bubbles in the left cardiac chambers about 3 cardiac beats after appearance in the right chambers but no structural cardiac defect or pulmonary hypertension. Compute tomographic angiography of the chest was normal and did not reveal any large pulmonary arteriovenous shunt. So with the possibility of multiple small intrapulmonary shunts he was further evaluated for any hepatoportal disease. Liver function tests and arterial plasma ammonia levels were normal; upper gastrointestinal endoscopy was normal. Doppler ultrasonography of the hepatoportal system (Figure A), contrast magnetic resonance imaging of the abdomen (Figure B, C) were done for further evaluation which revealed an abnormal vascular channel in the liver (arrow) and barely visible intrahepatic portal venous radicals (IHPVR; asterisk). What is the most likely diagnosis? See the GASTROENTEROLOGY web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.