In the absence of non-thyroid illness, this phrase is used to characterize clinically euthyroid patients with normal serum thyroid hormone concentrations in the upper half of the reference range and undetectable TSH.
Hypertension (high blood pressure) can be caused by hyperthyroidism.
One of the symptoms of an overactive thyroid is high blood pressure (hyperthyroidism). Beta blockers, which are commonly used to treat hypertension, can disguise hyperthyroidism symptoms.