Children with irreversible brain damage associated with hypothyroidism and multiple intracranial calcifications.

Children who develop clinical hypothyroidism in early childhood have various degrees of irreversible brain damage, albeit less severe than cases detected by neonatal screening test for hypothyroidism in the first months of the life. We report three patients with hypothyroidism of childhood onset after a normal neonatal thyroid-stimulating hormone screening who showed deceleration in linear growth, spasticity in the lower limbs with deformity, mild intellectual impairment, and multiple calcifications in the basal ganglia and subcortical areas. The neurologic symptoms were not progressive but were irreversible in spite of thyroxine treatment. Motor disturbances commonly observed in postnatal-onset hypothyroidism are similar to those of cerebral palsy. Specific distribution of intracranial calcifications may result from metabolic derangement as a result of hypothyroidism, although the mechanism of calcification is not fully understood. We emphasize the need to re-evaluate thyroid function in diplegic patients with specific intracranial calcifications but normal neonatal thyroid-stimulating hormone screening.