N. Yamakita et al., Usefulness of thyrotropin (TSH)-releasing hormone test and nocturnal surgeof TSH for diagnosis of isolated deficit of TSH secretion, J CLIN END, 86(3), 2001, pp. 1054-1060
Six patients with idiopathic isolated deficit of TSH secretion were examine
d and reported on. Their clinical symptoms and routine biochemical data wer
e unclear and were not specific for hypothyroidism. Serum triiodothyronine,
free thyroxine and TSH levels were slightly low or low-normal. Basal metab
olic rate and thyroidal I-123-uptake were also slightly low or low-normal.
The response of serum TSH to TRH stimulation was blunted in all patients. N
o nocturnal surge of serum TSH level could be seen in any of the patients.
Empty sella was revealed in three patients, and pituitary microadenoma in o
ne patient via magnetic resolution imaging. Antihuman pituitary cytosol ant
ibody was seen in five patients. Autoimmunity may have played a role in the
pathogenesis of idiopathic isolated TSH deficiency.
Routine examination of thyroid function cannot easily detect this disease.
TSH response to TRH stimulation and nocturnal surge of TSH should be examin
ed when this disease is suspected.