Hypothyroidism

“The clinical effect of lack of thyroid hormones”

Aetiology & Pathogenesis

• Primary Autoimmune Hypothyroidism:
  • Primary Atrophic Hypothyroidism
    • No goitre
    • Diffuse lymphocytic infiltration of the thyroid, leading to atrophy
  • Hashimoto’s Thyroiditis
    • Goitre due to lymphocytic + plasma cell infiltration
    • May be hypothyroid or euthyroid

• Other Primary Hypothyroidism:
  • Iodine Deficiency
  • Post-Thyroidectomy / Radioiodine treatment
  • Drug-induced i.e. Antithyroids, Amiodarone, Lithium, Iodine
  • Subacute Thyroiditis
    • Temporary hypothyroidism after hyperthyroid phase

• Secondary Hypothydoisim:
  • Not enough TSH due to Hypopituitarism
  • Very rare

Clinical Presentation

Investigations

• Bloods:
  • High TSH
  • Low T4
  • High Cholesterol + Triglycerides
  • Macrocytosis
• Imaging: n/a
• Special: n/a

Management

• Levothyroxine

Complications

• Myxoedema Coma
• Pregnancy
  • Eclampsia
  • Anaemia
  • Prematurity
  • Low birth weight
  • Stillbirth