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.