https://youtu.be/wyanDtvx8K0

Overview

• Clinical condition resulting from low free T3 and T4
• Prevalence of 1-2% of general population
  • Much more common in women (10:1)
• Associated with other autoimmune diseases

Causes

• Split into primary and secondary

Primary causes

• Hashimoto's thyroiditis
• Subacute thyroiditis (de Quervain's)
• Riedel thyroiditis
• Sick Euthyroid syndrome
• After thyroidectomy or radioiodine treatment
• Drug therapy - antithyroid drugs
• Lithium
• Amiodarone
• Dietary iodine deficiency 🥑

Secondary causes (central causes)

• This is due to pituitary failure 🧠
  • Failure to produce enough TSH
  • Often associated with a lack of other pituitary hormones like ACTH
• Causes
  • Tumours
  • Infection
  • Vascular - Sheehan syndrome
  • Radiation