SAT-075 Pulmonary Hypertension in a Patient with Neonatal Graves Disease

INTRODUCTION Neonatal hyperthyroidism is a transient disorder seen in neonates born to mothers with current or past history of Graves’ disease. We present a rare case of a Neonatal Graves’ disease with pulmonary hypertension (PH) which completely resolved with treatment of hyperthyroidism. CLINICAL CASE Baby B was a 3200 g term male born to a 40-year-old hypothyroid mother. He was prenatally diagnosed with Trisomy 21 and coarctation of the aorta (CoA). He developed respiratory distress soon after birth and was admitted to the NICU. His echocardiogram (echo) showed a large patent ductus arteriosus (PDA) and increased tortuosity of juxtaductal aorta with no significant gradient. Near-systemic pulmonary artery pressure was noted in the absence of any evidence of left heart failure. Cardiology determined his CoA to be hemodynamically insignificant and not the cause of his PH. Successive trials of 100% FiO2, Nitric Oxide (NO), and Sildenafil resulted in only minimal improvement of his PH. Thyroid function tests (TFT) obtained on day of life (DOL) 8 showed serum TSH of 0.01 uIU/ml [0.87 - 6.43] and FT4 of 3.5 ng/dl [0.9 - 1.5]. Further interaction with the mother revealed that she had a history of Graves’ disease treated with radioactive iodine (RAI) and resultant hypothyroidism. Baby B’s TSH receptor antibody (TRAb) and thyroid stimulating immunoglobulin levels were elevated at 7.38 IU/l [0-1.75] and 3.38 IU/l [0-0.55], respectively. He was thus diagnosed with Neonatal Graves’ disease and was started on Methimazole (MTZ) 1 mg/kg/day on DOL 8. Subsequently, potassium iodide was added. FT4 showed gradual normalization by DOL 15. Beta blockers were not added due to absence of hypertension or significant tachycardia. Serial echo showed improvement of PH, consistent with the decline in FT4 levels. Sildenafil and FiO2 were slowly weaned and discontinued by DOL 30. MTZ was then tapered and discontinued. A final echo showed complete resolution of PH, unobstructed aortic arch and persistent PDA. DISCUSSION Neonatal hyperthyroidism occurs due to transplacental transfer of TRAb from mother to fetus, stimulating the fetal thyroid to make excessive thyroid hormones. Risk correlates with TRAb titers in the mother. Our patient had pulmonary hypertension which did not resolve with FiO2, NO and Sildenafil. However, it showed complete resolution with normalization of FT4 levels by antithyroid drugs. Hyperthyroidism commonly presents with systemic HTN, but we found 3 neonatal cases in the literature presenting with PH that resolved with treatment of hyperthyroidism. The mechanism is unclear, but hypotheses include increased clearance of pulmonary vasodilators and decreased clearance of pulmonary vasoconstrictor and decreased surfactant production/function(1). REFERENCES 1) Oden J, Cheifetz IM. Neonatal thyrotoxicosis and persistent PH necessitating extracorporeal life support. Pediatrics 2005-115: e105-8.