Hyperthyroidism

Background

Etiologies

• Graves disease (autoimmune)
• Thyroiditis
  • Viral (painful, subacute)
  • Autoimmune
    • Transient (painless)
    • Post-partum thyroiditis (painless)
• Toxic nodule
• Toxic multinodular goitre
• Iatrogenic
  • Amiodarone
  • Lithium

Clinical Manifestations

Biochemical

• Laboratory dysfunction only

Subclinical

• Progresses to symptomatic hyperthyroidism in 25% by 5 years

Clinical

• History
  • Heat intolerance
  • Weight loss
  • Anxiety
  • Emotional ability
  • Weakness
  • Tremor
  • Palpitations
  • Increased perspiration
  • Distractibility
• Signs & Symptoms
  • Atrial fibrillation

Graves Disease

• Signs and symptoms of hyperthyroidism
• Diffuse goitre
• Proptosis, palpebral swelling
• Diffuse dermopathy

Investigations

• Labs
  • TSH; if low, repeat and add free T3 and free T4
• Imaging
• Other

Management

• Depends on the underlying cause
• Methimazole
  • Free T4 levels 1 to 1.5 times ULN: 5 to 10 mg once daily
  • Free T4 levels >1.5 to 2 times ULN (or iodine-induced thyrotoxicosis): 10 to 20 mg once daily
  • Free T4 levels >2 times ULN: 20 to 40 mg/day
  • Give in 2 to 3 divided doses to minimize GI side effects
  • Propylthiouracil preferred in pregnant patients
• Beta blockers
  • Atenolol 25 to 50 mg p.o. daily, titrate up to get heart rate under 90 (as BP allows) to maximum of 200 mg daily in two divided doses
  • Propanolol