Hyperthyroidism

Disease of excess thyroid hormone, which leads to a constellation of symptoms. Hyperthyroidism may be classified into:

This covers general considerations of hyperthyroidism; thyroid storm is covered at Thyroid Storm.

• Primary
  Excess secretion of hormone from thyroid gland, further divided into:
  • Overt
    Elevated thyroid hormone with suppressed TSH.
  • Subclinical
    Normal thyroid hormone levels with suppressed TSH.
• Secondary
  Excessive TSH production from pituitary gland.

Epidemiology and Risk Factors

Risk factors:

• Female:Male is 2:1

Pathophysiology

Aetiology

Include:

• Grave’s disease
• Toxic nodular goitre
• Thyroiditis
• Drug induced
  • Amiodarone

Clinical Manifestations

History

Examination

Diagnostic Approach and DDx

Investigations

Management

Anaesthetic Considerations

• B
  • ↓ Apnoea time due to ↑ VO₂
• C
  • ↑ HR
  • Arrhythmia
    • AF
  • CCF
  • IHD
• E
  • Heat intolerance
  • Weight loss
• E₂
  • Thyroid state
    Patients should be euthyroid preoperatively to avoid thyroid storm.
    • Carbimazole
      ↓ Iodine uptake and inhibits peroxidase enzyme, preventing iodine coupling.
    • Propothiouracil
      Inhibits thyroperoxidase, and also ↓ T₄ to T₃ conversion.
    • Steroids
      ↓ T₄ to T₃ conversion.
    • Lugol’s Iodine
    • β-blockers
  • Thyroid storm may occur up to 18 hours post-operatively

Marginal and Ineffective Therapies

Complications

• C
  • AF
    10-40% incidence.
  • Palpitations
  • CHF
• E
  • ↑ Incidence of myasthenia gravis
  • Thyroid storm
• H
  • Thyrombocytopenia
  • Anaemia

Prognosis

Key Studies

---

References

1. Bersten, A. D., & Handy, J. M. (2018). Oh’s Intensive Care Manual. Elsevier Gezondheidszorg.