Conditions where it may occur:
(1) malnutrition, starvation, anorexia nervosa
(2) multiple trauma
(3) sepsis
(4) after major surgery
(5) after myocardial infarction
(6) after bone marrow transplantation
(7) renal failure
(8) drugs (dopamine, glucocorticoids, others)
(9) any serious illness
Laboratory findings:
(1) reduced free T3
(2) variable reduction in free T4
(3) variable reduction in serum thyrotropin (TSH)
(4) variable increases in total reverse T3
|
Free T3
|
Free T4
|
Thyrotropin
|
Stage
|
|
reduced up to 50%
|
normal
|
normal
|
mild
|
|
reduced up to 90%
|
may be increased
|
normal
|
moderate
|
|
almost undetectable
|
reduced
|
reduced
|
severe
|
from Table 10-10, page 351, Larsen et al (2003)
Clinical significance:
(1) A euthyroid patient may be misdiagnosed as hypothyroid.
(2) A hyperthyroid patient may be misdiagnosed as euthyroid.
(3) The presence of the severe form is a poor prognostic sign, reflecting the seriousness of the systemic illness.
A patient with a serious systemic illness should have thyroid function tests interpreted with caution. Investigation of thyroid status should await recovery from the concurrent disease.
