Myotonic Dystrophy

Epidemiology and Risk Factors

Pathophysiology

Aetiology

Clinical Manifestations

Diagnostic Approach and DDx

Investigations

Management

Medical

Surgical

Anaesthetic Considerations

  • General
    • Low threshold for HDU monitoring
      ↑ risk of apnoea and death for 24 hours following extubation.
  • A
    • Limited mouth opening
    • Bulbar palsy and aspiration risk
  • B
    • Respiratory muscle weakness and expectoration
      Pulmonary complications are the most common cause of peri-operative morbidity.
    • OSA
  • C
    • Cardiomyopathy
    • Conduction abnormalities
  • D
    • ↑ sensitivity to IV induction agents
      • Addition of lignocaine may reduce the incidence of contractures
    • Shivering from neuraxial anaesthesia may precipitate myotonic contractures
    • Regional techniques ideal to reduce analgesia and opioid requirements
  • E
    • Hypothermia
      Avoid shivering.
    • Avoid suxamethonium
      May result in severe hyperkalaemia.
    • Avoid muscle relaxation where possible
      Reduce initial doses and titrate with a nerve stimulator.
  • E
    • DM
    • Hypothyroidism
    • Adrenal insufficiency
    • Gonadal atrophy
  • O
    • Neuraxial anaesthesia preferred for labour and caesarian delivery
    • Tocolytic medications are problematic
      • β2-agonists may precipitate myotonia
      • MgSO4 may precipitate respiratory depression

Marginal and Ineffective Therapies

Complications

Prognosis

Key Studies


References