Severe hypothyroidism due to atrophic thyroiditis from second year of life influenced developmental outcome

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. 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.