Is There Compensated Hypothyroidism in Infancy?
Ramin Alemzadeh MD1, Silvia Friedman PhD1, Pavel Fort MD1, Bridget Recker RN, EdM1, , Fima Lifshitz MD1 1 From the Department of Pediatrics, North Shore University Hospital-Cornell University Medical College, Manhasset, NY; and Department of Pediatrics, Maimonides Medical Center, Brooklyn, NY The state-mandated newborn thyroid screening program may uncover infants who exhibit normal thyoxine (T4) levels with various degrees of hyperthyrotropinemia. To elucidate further the thyroid status, the basal metabolic rate (BMR) of 10 infants (7 boys, 3 girls; aged 9 to 63 days) was studied by indirect calorimetry. They were clinically euthyroid and healthy with no evidence of overt biochemical hypothyroidism (low T4, high thyroid-stimulating hormone [TSH]). Confirmatory testing indicated that all infants had normal serum T4 levels for age (mean ± SD: 10.3 ± 3.2 µg/dL). However, serum TSH levels varied from 2.3 to 99.2 µU/mL In 4 infants (2 boys, 2 girls) the BMR was low (38.1 ± 4.1 kcal/kg per
