Extraordinarily High Brain Natriuretic Peptide (BNP) Level in a Case of Thyroid Storm.

Thyroid storm is an extreme manifestation of thyrotoxicosis and represents a life-threatening endocrine emergency. Here, we report a 51-year-old woman with severe thyrotoxicosis and markedly elevated brain natriuretic peptide (BNP) level of 9950 pg/mL. Cardiac evaluation revealed poor left ventricular systolic performance. While thyroid function can affect BNP level, such extreme elevation is rare in cases of thyrotoxic crisis. This case highlighted the discrepancy between the clinical course and BNP level, emphasizing the need to recognize that BNP level may not always accurately reflect cardiac function in thyroid storm.