Low TSH, raised free thyroid hormones
A depressed TSH with elevated free T3 or T4 is characteristic of primary hyperthyroidism. In most cases the radioiodine thyroid scan will show increased signal.
The common causes of primary hyperthyroidism are:
- Grave's disease:
- 90% have anti-thyroid antibodies
- diffuse uptake on an radioiodine scan
- multinodular goitre
- toxic nodule
Other diagnoses to consider are:
- transient thyroiditis:
- may be subacute, silent or post-partum
- usually a short history
- rapid return to euthyroidism with treatment
- De Quervain's thyroiditis:
- raised ESR and a tender thyroid are supportive
Reference:
- Thyroid Function Tests. British Thyroid Foundation, revised 2021
Related pages
Create an account to add page annotations
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.