Let’s go on to another case.
A 70 year old man is seen in the hospital 4 days
after he was admitted with a myocardial infarction.
He underwent cardiac catheterization
and stent placement.
He is feeling much better and has no history of thyroid
disease or family history of endocrine diseases.
On exam, his vital signs are normal and
his physical exam is unremarkable.
His labs are significant for TSH of 0.2 microunits
per ml, a free T4 and T3 which are mildly decreased.
What is the most likely cause of
this patient’s lab abnormalities?
Here we have a patient in the hospital who has
a discrepancy between his clinical course
and his abnormal labs.
The TSH is low, based on the lower limits
of normal being 0.4 (microunits/mL).
what is the most likely
cause of this condition?
Here we are considering the
euthyroid sick syndrome.
The euthyroid sick syndrome occurs when critical
illness causes changes in thyroid function tests.
and this can occur in up to 75%
of all hospitalized patients.
TSH should only be obtained in a hospital when there
is high clinical suspicion of thyroid dysfunction.
The typical pattern which occurs in this condition
is initially, there is a low T4 and T3.
Subsequently as the patient becomes
more ill, the TSH level also decreases.
As the patient then enters the recovery phase,
the T3 and T4 levels remains likely low
but the TSH level becomes mildly elevated.
The plan here is to do a follow
up thyroid function test
but this should not be repeated at least until 6
weeks after discharge from the hospital.