Question

A 38-year-old woman presents complaining of weight loss, agitation, and new-onset tremor. The nurse practitioner suspects hyperthyroidism. Laboratory assessment will most likely include:

a) TSH=8.9 mIU/L (0.4-4.0 mIU/L), free T4 =15 pmol/L (10-27 pmol/L).
b) TSH<0.15 mIU/L (0.4-4.0 mIU/L), free T4 =79 pmol/L (10-27 pmol/L).
c) TSH=24 mIU/L (0.4-4.0 mIU/L), free T4 =3 pmol/L (10-27 pmol/L).
d) TSH=1.9 mIU/L (0.4-4.0 mIU/L), free T4 =22 pmol/L (10-27 pmol/L).

Answer 1

The most likely laboratory assessment indicating hyperthyroidism is option b) TSH<0.15 mIU/L, free T4 =79 pmol/L, with TSH below and free T4 above their respective normal ranges. Such an imbalance in levels indicates an overproduction of thyroid hormones, leading to an increased metabolic rate and symptoms like weight loss and agitation.

Step-by-step explanation:

The laboratory assessment most likely to indicate hyperthyroidism is b) TSH<0.15 mIU/L (0.4-4.0 mIU/L), free T4 =79 pmol/L (10-27 pmol/L). In this result, the TSH level is significantly below the normal range, while the free T4 level is above the normal range, which is indicative of hyperthyroidism. This condition leads to an overproduction of thyroid hormones (T3 and T4), causing symptoms like weight loss, agitation, and tremor.

When the thyroid gland releases excessive amounts of thyroxine (T4) and triiodothyronine (T3), it results in an increased metabolic rate. These hormones control how the body uses energy, and overproduction can accelerate bodily functions, leading to the symptoms described. Thyroid function tests, specifically measuring serum TSH and free T4, are crucial for diagnosing thyroid disorders such as hyperthyroidism.