Causes

Autoimmune:

• Hashimotos thyroiditis
  • Anti-TPO (thyroperoxidase): 90-95% of patients
  • Anti-thyroglobulin: 35-60% of patients
  • Anti-TSH receptor (blocking): 10% of patients
• Atrophic thyroiditis
• Autoimmune polyendocrine syndromes

Iatrogenic:

• Surgical
• Radioablation
• Radiation

Congenital:

• Thyroid aplasia
• Pendred syndrome (defect in thyroxine synthesis)

Epidemiology:

• In the UK, the most common cause of congenital hypothyroidism is a failure in thyroid development or migration.
• Globally, the most common cause of congenital hypothyroidism is iodine deficiency.

Clinical features

Peripheral features:

• Dry, thick skin