Parameters to monitor in the neonate:
(1) serum antibodies to thyrotropin-receptor
(2) serum T3 and T4 (free and total)
(3) serum thryotropin (TSH)
(4) clinical symptoms
The assay for antibodies to thyrotropin receptor (Endocrine Sciences) had the following references ranges:
|
Serum Level (reported in binding inhibition)
|
Interpretation
|
|
< 0.10
|
negative
|
|
0.10 - 0.15
|
indeterminate
|
|
> 0.15
|
positive
|
A neonate with hyperthyroidism has:
(1) elevated levels of antibodies to thyrotropin receptor (usually > 0.25 binding inhibition)
(2) elevated free and total T3 and/or T4
(3) depressed levels of thyrotropin
(4) variable signs and symptoms of hyperthyroidism (jitteriness, poor feeding, tachycardia)
An infant with a low or indeterminate level of antibodies to thyrotropin receptor did not develop hyperthyroidism.
Treatment with propylthiouracil was continued for up to 4 months.
Antithyroid therapy was discontinued when:
(1) thyrotropin receptor antibodies were no longer elevated
(2) serum T3 and T4 were in the normal range
(3) there was no clinical evidence of hyperthyroidism
