Myotonic dystrophy risk, peripheral hospital

26yo female for laparoscopic cholecystectomy at a small peripheral hospital.


  • Myotonic dystrophy type II “carrier” (based on genetic testing)
    • Father developed symptoms at 60yo
    • Thought likely that this patient will have the same progression, but currently asymptomatic
    • Uneventful muscle relaxant anaesthesia previously.
  • Open ASD repair ’20. Incidental finding after Ix for atypical chest pain.
  • Normal TTE post ASD repair.
  • Neuropathic chest wall pain
  • 3 x episodes of cholecystitis requiring hospitalisation


  • Correct care location (small peripheral hospital, no ICU)


  • Care location
    • Reassured by absence of clinical symptoms of MD and by recent uneventful anaesthetics
  • Surgery needed?
    • Multiple hospital admissions. Consensus was that surgery should proceed or more severe episodes and requirement for emergency procedures will ensue. 
  • What are myotonic disorders?
    • Persisting active muscle contraction after cessation of effort.
    • Myotonic dystrophy is the most common form, caused by altered chloride conductance.
    • Onset usually in 20-40s, death by 50-60s
    • Extramuscular features include
      • CVS: conduction abnormalities, cardiomyopathy, mitral valve prolapse
      • RS: restrictive defect, OSA
      • Other: delayed gastric emptying, dysphagia, hypothyroidism, DM, intellectual impairment, baldness, testicular atrophy. 
    • Obstetric implications: exacerbation of muscular and CVS effects, uterine dysfx leading to CS and PPH, preterm labour.
    • Anaesthetic implications:
      • Avoid exacerbants: cold, shivering, DMR, surgical manipulation and diathermy
      • Resistance to NDMR
      • High muscle tone despite regional anaesthesia
      • AChE may provoke contraction
      • CVS/RS depressant sensitivity
      • MH association
      • Aspiration risks


  • Proceed with surgery as planned.