Congenital hypothyroidism (CHT), previously known as cretinism, can be of thyroidal or central (hypothalamic/pituitary) origin and can have a widely diverse molecular etiology.
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Clinical presentation
Most children are asymptomatic at birth and are diagnosed after screening. In untreated congenital hypothyroidism, patients can present with short stature, disproportionately enlarged heads and/or developmental delay / intellectual disability 5.
Pathology
Etiology
-
disorders in development of the thyroid gland
- thyroid is absent
- underdevelopment with migration failure (i.e. ectopic thyroid)
- underdevelopment with normal migration
- certain fetal goiters can also give hypothyroidism 4
-
disorders in thyroid hormone synthesis
- TSH hyporesponsiveness
- defects in iodide transport from circulation into the thyroid
cell - defects in iodide transport from the thyroid cell to the
follicular lumen, often combined with inner ear deafness (Pendred syndrome) - defects in the synthesis of hydrogen peroxide
- defects in the oxidation of iodide, iodination and
iodothyronine synthesis - defects in processes involved in the synthesis or degradation of thyroglobulin
- detects in iodine recycling
-
central congenital hypothyroidism
- disorders in development and/or function of the
- hypothalamus
- pituitary gland
- both
- disorders in development and/or function of the
Radiographic features
Plain radiograph
- delayed skeletal maturation
- bone age can be assessed by the Greulich & Pyle method with a PA left hand radiograph
- bone epiphyses/ossification centers are absent or small
- cortical thickening