A 15-DAY-OLD premature infant (gestational age, 32 weeks) was noted to have a prominent midline neck mass (Figure). Thyroid function studies revealed the following values: thyroxine, 12.87 nmol/L (1 μg/dL) (normal range, 58-154 nmol/L [4.5-12 μg/dL]); triiodothyronine, 1.2 nmol/L (80 ng/dL) (normal range, 1.3-3.1 nmol/L [87-200 ng/dL]); and thyroid-stimulating hormone, 95 mU/L (normal range, 1.7-9.1 mU/L). There was no history of maternal ingestion of goitrogenic medications or excessive exposure to iodine-containing substances. Thyroxine replacement (10 μg/kg per day) was begun; the goiter disappeared within 2 weeks, and the abnormal thyroid function test results reverted to normal by the time the patient was 4 months old.
Denouement and Discussion
Transient Primary Hypothyroidism
Transient primary hypothyroidism (TPH) is a temporary hypofunction of the thyroid gland, more common in some parts of the world than in others. The abnormal thyroid function persists for a variable time after birth and is often related to
Böber E, Eroğlu Y, Tunnessen WW. Picture of the Month. Arch Pediatr Adolesc Med. 1996;150(10):1099-1100. doi:10.1001/archpedi.1996.02170350101019