Congenital hypothyroidism

Congenital hypothyroidism (CHT), previously known as cretinism, can be of thyroidal or central (hypothalamic/pituitary) origin and can have a widely diverse molecular aetiology.

Clinical presentation

Most children are asymptomatic at birth and are diagnosed after screening. In untreated CHT patients can present with short stature, disproportionately enlarged head, and/or developmental delay / intellectual disability ⁵.

Pathology

Aetiology

• disorders in development of the thyroid gland
  • thyroid is absent
  • under-development with migration failure
  • under-development with normal migration
  • certain fetal goitres can also give hypothyroidism ⁴
• disorders in thyroid hormone synthesis
  • TSH hypo-responsiveness
  • defects in iodide transport from circulation into the thyroidcell
  • defects in iodide transport from the thyroid cell to thefollicular lumen, often combined with inner ear deafness(Pendred syndrome)
  • defects in the synthesis of hydrogen peroxide
  • defects in the oxidation of iodide, iodination andiodothyronine 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

Radiographic features

Plain radiographs radiograph

• delayed skeletal maturation

  • bone age can be assessed by the Greulich & Pyle method with PA left hand radiograph

• bone epiphysis/ossification centres are absent or small
  • stippled epiphysis appearance
• cortical thickening