Etiology
Primary causes:
- Iodine deficiency (dietary)
- Transient thyroiditis: postpartum, de Quervain’s
- Autoimmune: Hashimoto’s thyroiditis
- Post-surgical/ablation
- Drug-induced: lithium, amiodarone, sodium valproate, rifampicin, anti-thyroid medications
- Infiltrative: TB, metastases, sarcoidosis, lymphomas, amyloidosis
Secondary causes:
- Pituitary adenomas
- Pituitary infiltration
- Sheehan syndrome (postpartum pituitary necrosis)