Which of the following is a sign of thyrotoxic crisis in Graves' disease?

• A. Pallor
• B. Bradycardia
• C. Weight gain
• D. Fever

Answer: (D)

Fever is a sign of thyrotoxic crisis. In this extreme hypermetabolic state powered by very high thyroid hormone levels, heat production surges and the body's ability to regulate temperature is overwhelmed, leading to high fever often accompanied by sweating, tremor, agitation, and rapid heart rate. Among the options, fever best fits the picture of a thyroid storm in Graves' disease, which is a medical emergency requiring urgent treatment. Pallor isn’t a defining feature, bradycardia conflicts with the typical rapid heart rate, and weight gain is not typical in thyrotoxicosis ( weight loss due to increased metabolism is more common).