When to suspect THR:
(1) family history of THR
(2) unusual pattern of clinical and laboratory findings
(3) absence of other explanations for the findings, including pituitary adenoma or autoimmune disease
Unusual patterns of clinical and laboratory findings:
(1) clinically hyperthyroid with (a) elevated serum TSH and (b) elevated serum thyroid free hormone levels
(2) clinically hypothyroid with (a) normal or elevated serum TSH and (b) normal or elevated serum thyroid free hormone levels
(3) euthyroid with (a) elevated serum TSH and (b) elevated serum thyroid free hormone levels
(4) clinically hypothyroid patient who does not respond as expected to appropriate thyroid hormone replacement
The variations in the pattern of findings is determined by which sites are hormone resistant (pituitary only, generalized except the pituitary, generalized involving the pituitary).
