A 65-year-old man presents to his GP with vision loss, headaches and cold intolerance. He also mentions he has unintentionally gained 5kg in the last 3 months. On examination, he is found to have a bitemporal hemianopia and a pulse of 50 bpm. A thyroid function test is ordered. Which of the following test results is most likely to belong to this patient?
Cold intolerance & Weight gain (etiology hypothyoidism) Visual deficit - Bitemporal hemianopnia (pituitary adenoma may be the cause) Secondary (or central) hypothyroidism is caused by disorders of the pituitary gland or hypothalamus. Generally, secondary hypothyroidism is associated with low TSH and low T3 and T4. However, TSH levels may also be normal or even slightly elevated. For this reason, TSH is often an unreliable measure of secondary hypothyroidism and should not be used to assess the adequacy of thyroid replacement in these patients Clinical Diagnosis of 2o Hypothyroidism (pituitary affected) TSH || T4|| T3||
TSH: Low T4: Low T3: Low
TSH: high T4: low T3: low
TSH: high T4: normal T3: normal
TSH: low T4: high T3: high
Diseases of Thyroid