From the second year of life a girl showed an insidious development of clinical hypothyroidism due to a non-goitrous lymphocytic thyroiditis without traceable circulating levels of thyroid antibodies measured by routine immunoassays. The diagnostic delay of this rare variant of atrophic thyroiditis caused persistent neuropsychological deficits.
Conclusion: Her difficulties with speed of processing and working memory in particular could suggest a frontal deficit, possibly in the dorsolateral prefrontal circuit. This contrasts with findings in congenital hypothyroidism, suggesting a relatively preserved frontal function, and could illustrate different neuropsychological deficits of hypothyroidism at different ages in early childhood.