A 52-year-old patient presents with palpitations, tachycardia, tremors, weight loss, and heat intolerance. Which diagnosis best fits and what thyroid test pattern is expected?

A 52-year-old patient presents with palpitations, tachycardia, tremors, weight loss, and heat intolerance. Which diagnosis best fits and what thyroid test pattern is expected?

• A. Hyperthyroidism with low TSH and high T4
• B. Addison's disease
• C. Hypothyroidism
• D. Cushing syndrome

Answer: (A)

Excess thyroid hormone production best fits these symptoms. When the thyroid is overactive, it signals the pituitary to reduce TSH, so the TSH level falls. At the same time the thyroid pumps out more hormone, so free T4 is elevated (and sometimes free T3 is as well). So the most consistent thyroid test pattern is a low TSH with a high free T4. Other conditions don’t match this symptom cluster as well. Addison’s and Cushing’s have different sets of signs and laboratory clues, and hypothyroidism would cause weight gain and slowed metabolism with cold intolerance and often a high TSH or normal/low T4, not the elevated thyroid hormones seen here.

Excess thyroid hormone production best fits these symptoms. When the thyroid is overactive, it signals the pituitary to reduce TSH, so the TSH level falls. At the same time the thyroid pumps out more hormone, so free T4 is elevated (and sometimes free T3 is as well). So the most consistent thyroid test pattern is a low TSH with a high free T4.

Other conditions don’t match this symptom cluster as well. Addison’s and Cushing’s have different sets of signs and laboratory clues, and hypothyroidism would cause weight gain and slowed metabolism with cold intolerance and often a high TSH or normal/low T4, not the elevated thyroid hormones seen here.