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

Background

• 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

Issues

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

Discussion

• 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

Plan

• Proceed with surgery as planned.