Is there compensated hypothyroidism in infancy?

Ramin Alemzadeh, S. Friedman, P. Fort, B. Recker, F. Lifshitz

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The state-mandated newborn thyroid screening program may uncover infants who exhibit normal thyoxine (T 4 ) 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 T 4 , high thyroid- stimulating hormone [TSH]). Confirmatory testing indicated that all infants had normal serum T 4 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 day), while the other 6 patients (5 boys, 1 girl) demonstrated BMRs within the normal range (49.6 ± 1.9 kcal/kg per day, P < .001). The serum TSH levels were above 7.0 μU/mL among those infants with a low BMR, whereas the serum TSH levels were always below 6.0 μU/mL among the normometabolic infants. All infants who had a low BMR received thyroid therapy and promptly became normometabolic (BMR: 48.7 ± 1.0 kcal/kg per day) with suppression of TSH levels (3.2 ± 1.3 μU/mL) within 3 weeks of therapy, while their serum T 4 levels remained within the normal range. The observed normalization of BMR in parallel to reduction of TSH levels following thyroid replacement therapy strongly suggests that these patients demonstrated a hypometabolic state, despite normal serum T 4 levels. Therefore, the assessment of BMR may help define subclinical hypothyroidism in infancy in conjunction with a close monitoring of TSH concentration.

Original languageEnglish (US)
Pages (from-to)207-211
Number of pages5
JournalPediatrics
Volume90
Issue number2
StatePublished - Jan 1 1992
Externally publishedYes

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Basal Metabolism
Thyrotropin
Hypothyroidism
Thyroid Gland
Serum
Reference Values
Indirect Calorimetry
Therapeutics
Newborn Infant

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health

Cite this

Alemzadeh, R., Friedman, S., Fort, P., Recker, B., & Lifshitz, F. (1992). Is there compensated hypothyroidism in infancy? Pediatrics, 90(2), 207-211.

Is there compensated hypothyroidism in infancy? / Alemzadeh, Ramin; Friedman, S.; Fort, P.; Recker, B.; Lifshitz, F.

In: Pediatrics, Vol. 90, No. 2, 01.01.1992, p. 207-211.

Research output: Contribution to journalArticle

Alemzadeh, R, Friedman, S, Fort, P, Recker, B & Lifshitz, F 1992, 'Is there compensated hypothyroidism in infancy?', Pediatrics, vol. 90, no. 2, pp. 207-211.
Alemzadeh R, Friedman S, Fort P, Recker B, Lifshitz F. Is there compensated hypothyroidism in infancy? Pediatrics. 1992 Jan 1;90(2):207-211.
Alemzadeh, Ramin ; Friedman, S. ; Fort, P. ; Recker, B. ; Lifshitz, F. / Is there compensated hypothyroidism in infancy?. In: Pediatrics. 1992 ; Vol. 90, No. 2. pp. 207-211.
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