Table 3

Causes of hypothyroidism (in decreasing order of frequency)

Hashimoto's disease
131I therapy for hyperthyroidism
Subtotal thyroidectomy for hyperthyroidism or tumour
Previous antithyroid drug therapy
Postpartum (60%–70% transient)
Drugs (lithium, amiodarone, iodides interferon alfa)
Pituitary hypothyroidism (secondary)
Hypothalamic hypothyroidism (tertiary)
Subacute thyroiditis, silent thyroiditis
Iodine deficiency
Generalised resistance to thyroid hormone
Neonatal hypothyroidism
 Thyroid agenesis
 Thyroid ectopia
 Thyroid dyshormonogenesis
Resistance to thyroid hormone
Isolated TSH deficiency