Growth retardation was observed in a majority of children with severe acquired primary hypothyroidism and Hashimoto’s thyroiditis which correlated significantly with the severity of hypothyroidism, according to a study in Experimental and Clinical Endocrinology & Diabetes.
Investigators retrospectively assessed thyroid function tests from a cohort at a tertiary pediatric university center from January 1, 2004, to December 31, 2012. Eligible participants were aged >3 years and had an initial thyroid-stimulating hormone (TSH) level of >30 mIU/L, T4 level <6 µg/dL, and/or fT4 level <8 pg/mL.
A total of 43 patients were included in the study and had a mean age at diagnosis of 10.6 years, 59% were prepubertal, and 88% were female. They had a median TSH level of 101 mIU/L, a median fT4 level of 3.55 pg/mL, and a median T4 level of 2.85 µg/dL.
Presenting symptoms that led to a thyroid function test included goiter, tiredness, growth retardation, weight gain, and problems concentrating. For 11 patients (26%), the thyroid function test was conducted during a routine blood test.
The severity of hypothyroidism had a significant negative correlation with TSH and fT4 or T4 (fT4: r= –0.55, P = .0016; T4: r= –0.82, P = .000006).
Thyroid ultrasonography was performed at diagnosis in 41 patients, of which 40 had common signs of thyroiditis, such as heterogeneous echotexture and hypervascularization. Ultrasonography showed that 27% of patients had goiter, 13% had normal thyroid size, and 1% had hypoplastic thyroid size.
Growth data were available for 42 patients, of which 75% had a negative height–standard deviation score (SDS) at diagnosis, which suggested a growth deficit compared with an age- and sex-matched reference cohort. Five patients had a manifest non-syndromic short stature with a height SDS < –2.
Researchers found a significant correlation between fT4 or T4 levels at diagnosis and mid-parental height (MPH) SDS at diagnosis (fT4: r = 0.53, P = .021; T4: r = 0.77, P = .0012). Catch-up growth after L-thyroxine therapy was significantly greater in prepubertal children (median delta [height SDS – MPH SDS] +0.5) than in pubertal children (median delta [height SDS – MPH SDS] –0.2) (P = .049).
The authors acknowledged their findings contradicted at least one other study which “reported a significantly lower height SDS at diagnosis in hypothyroid children with Hashimoto’s thyroiditis compared to a euthyroid Hashimoto’s thyroiditis subgroup,” while noting “this difference diminished during follow-up under treatment with LT4.”
“Remarkably, a quarter of these severely hypothyroid patients were discovered incidentally by random blood tests,” noted the study authors. “It might therefore be reasonable to consider a thyroid function test in every child with a decline in growth rate to avoid the development of more severe hypothyroidism and hence the risk of an irreversible impact on growth.”
Becker M, Blankenstein O, Lankes E, Schnabel D, Krude H. Severe acquired primary hypothyroidism in children and its influence on growth: a retrospective analysis of 43 cases. Exp Clin Endocrinol Diabetes. Published online October 4, 2021. doi:10.1055/a-1538-8241