A patient with diffuse toxic goiter has TSH 0.1 mIU/L, FT4 30 pmol/L, FT3 10 pmol/L; which diagnosis is most likely?

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Multiple Choice

A patient with diffuse toxic goiter has TSH 0.1 mIU/L, FT4 30 pmol/L, FT3 10 pmol/L; which diagnosis is most likely?

This pattern shows thyrotoxicosis with suppression of TSH and elevation of both free T4 and free T3. A very low TSH (0.1 mIU/L) alongside high FT4 (30 pmol/L) and high FT3 (10 pmol/L) points to overproduction of thyroid hormones rather than a transient release. Among the given possibilities, Graves disease best fits a diffuse toxic goiter: autoimmune stimulation of the TSH receptor drives widespread thyroid hormone production and diffuse gland enlargement, causing hyperthyroidism without a painful thyroid. Hashimoto’s disease typically leads to hypothyroidism (high TSH, low FT4). Subacute thyroiditis and silent thyroiditis can cause thyrotoxicosis, but they usually show reduced thyroid uptake and—especially with subacute thyroiditis—thyroid pain or a painful, inflamed gland, which isn’t implied here. So the most likely diagnosis is Graves disease.

This pattern shows thyrotoxicosis with suppression of TSH and elevation of both free T4 and free T3. A very low TSH (0.1 mIU/L) alongside high FT4 (30 pmol/L) and high FT3 (10 pmol/L) points to overproduction of thyroid hormones rather than a transient release.

Among the given possibilities, Graves disease best fits a diffuse toxic goiter: autoimmune stimulation of the TSH receptor drives widespread thyroid hormone production and diffuse gland enlargement, causing hyperthyroidism without a painful thyroid. Hashimoto’s disease typically leads to hypothyroidism (high TSH, low FT4). Subacute thyroiditis and silent thyroiditis can cause thyrotoxicosis, but they usually show reduced thyroid uptake and—especially with subacute thyroiditis—thyroid pain or a painful, inflamed gland, which isn’t implied here.

So the most likely diagnosis is Graves disease.

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