The symptoms are:
Modern assays combined with clinical suspicion make the diagnosis relatively easy. The following tests should be performed:
1) Thyroid Stimulating hormone (TSH)
If this is low it confirms hyperthyroidism, as long as the free thyroxine (T4) is raised. Low TSH levels will also occur in patients with pituitary failure but then the T4 is also low. Rarely the T4 is normal in thyrotoxicosis and only free triiodothyronine (T3) is secreted highlighting the importance in measuring T3. This latter condition is called T3 toxicosis.
2) A Radioactive Iodine or Technetium Scan
Uptake of tracer doses of technetium or iodine is an essential test and may show the following:
A thyrotoxic scan - click to enlarge
A low uptake or no uptake in the thyroid occurs in:
A diffuse uniform uptake in the thyroid occurs in:
A patchy uptake in the thyroid occurs in:
A solitary hot spot in the thyroid occurs in:
The importance of the thyroid scan is that the low uptake states and Plummer's disease are treated differently from Graves' disease and toxic nodular goitre.