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

## TL;DR

A woman with thyroid storm had an extremely high BNP level, showing that BNP may not always reflect true heart function in this condition.

## Contribution

This case highlights the rare occurrence of extremely elevated BNP levels in thyroid storm and challenges its reliability as a cardiac marker in this context.

## Key findings

- A patient with thyroid storm had a BNP level of 9950 pg/mL, far above normal ranges.
- Cardiac evaluation showed poor left ventricular systolic performance despite the high BNP.
- The case suggests BNP may not accurately reflect cardiac function in thyroid storm.

## Abstract

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.