Abstract Introduction Unexplained hypoxemia and digital clubbing in pediatric patients should raise suspicion for underlying vascular anomalies, notably pulmonary arteriovenous malformations (AVMs), and genetic disorders such as Hereditary Hemorrhagic Telangiectasia (HHT). Though they may be asymptomatic for years, these findings may indicate profound right-to-left shunting and predispose to neurologic and infectious complications, requiring prompt, systematic workup. Case Description A previously healthy seven-year-old boy presented for well child visit and was incidentally found to be hypoxemic, with an oxygen saturation of 70% in room air, despite the absence of respiratory distress. Physical examination revealed digital clubbing of both fingers and toes. Chest auscultation and cardiac examination were unremarkable. Lab findings demonstrated polycythemia (Hb 18.3), proBNP 36 and negative troponin. Transthoracic echocardiography revealed a structurally normal heart, but a positive bubble study consistent with extracardiac right-to-left shunting. Computed tomographic angiography (CTA) identified a large AVM of the left lower lobe (LLL). Additionally, his family history was positive for father having recurrent unprovoked nosebleeds requiring cauterization and an ASD/PFO in a maternal grandparent. The patient was admitted to the pediatric intensive care unit (PICU) and managed with oxygen via high-flow nasal cannula. He underwent embolization in multiple large feeding vessels arising from LLL segmental pulmonary artery branches. Additional feeders were seen but couldn’t be selectively catheterized for embolization. Subsequently, his saturations improved to the high 80s, and patient was transferred to quaternary center for additional embolization. Genetic testing confirmed a diagnosis of HHT. The patient continues to require multidisciplinary follow-up and prophylactic antibiotics before any invasive procedure. Discussion This case underscores the importance of recognizing subtle clinical findings, such as digital clubbing and unexplained oxygen desaturation as potential indicators of a clinically significant right-to-left shunt in pediatric patients. Notably, the patient had significant isolated hypoxemia, minimal symptoms, and classic signs suggestive of HHT, where early AVM embolization can improve oxygenation and reduce morbidity despite recurrence risk. Genetic confirmation not only guides targeted screening strategies for at risk family members but also emphasizes the need for an anticipatory approach within pediatric practice. This case highlights the critical value of maintaining a high index of suspicion, closely monitoring subtle clinical signs, and thoroughly evaluating family history to enable early diagnosis of potentially life-threatening conditions such as HHT with multiple AVMs. This abstract is funded by: None
Mishra et al. (Fri,) studied this question.