Thyroid dysfunction in HIV-infected children: is L-thyroxine therapy beneficial?

To assess thyroid function in symptomatic HIV-infected infants and children with failure to thrive and to evaluate clinical response in patients with hyperthyrotropinemia to levothyroxine.

We evaluated 11 children (mean age: 1.5 years; males = 5, females = 6) with HIV infection and failure to thrive (weight and height > 2 SD below the mean) for presence of hypothyroidism. Thyroid-stimulating hormone (TSH) and thyroxine (T4) were measured. Four children with high basal TSH and one child with a normal basal TSH underwent the Thyrotropin-releasing hormone (TRH) stimulation test as well. Four children received treatment with L-thyroxine.

Eight of the 11 children had high basal TSH levels. All patients had normal or increased T4 values. The TRH stimulation test showed an exaggerated response in all four patients with high basal TSH values and a normal response in one patient with normal basal THS values. All four patients who received treatment with L-thyroxine showed normalization of the TSH. Increased growth velocity was noted in 3 of 4 patients. The fourth patient died within two weeks following initiation of therapy for overwhelming candida sepsis. The autopsy of this patient showed atrophy of the thyroid gland. Two of the four patients with high TSH levels, who did not receive L-thyroxine, died; the other two did not show any improvement in their height z scores. Two patients with a high TSH also had high thyroid-binding hormone (TBG) levels. Both patients with the high TBG died within 2 to 3 months of the study.

Hypothyroidism as indicated by elevated basal TSH and abnormal TRH response was common in the HIV-infected children in this study and may have contributed to failure of growth in these children. Replacement therapy resulted in correction of abnormal TSH and improvement of height z scores during the period of observation. The significance of these findings needs to be confirmed in a larger prospective study.