Genetics:
Autosomal dominant
Ca++ ryanodine receptor 1 RYR1.
Ca++ CACN1A3 muscle DPH sensitive Ca++ channel
Clinical features:
Hyperthermia
Rigidity, tachycardia, hypertension, fever, rising CO2, lactic acidosis, rhabdomyolysis
Triggered by anesthetic administration e.g. halothane. Also suxamethonium
Findings on investigations:
Rhabdomyolysis
Muscle biopsy:
Normal or Non-specific changes
Or pre-existing underlying myopathy: central core disease. Some forms of myotonic syndromes.
Investigations to consider:
ABG
Creatine kinase
Urine Myoglobin
Basic metabolic panel
Treatment:
Stop anaesthesia
Give Dantrolene
If acidotic; give bicarbonate
Following surgeries:
Pre-treat with dantrolene four times daily on the preceding day
Atropine is contraindicated
Consider the following anaesthetics:
- Nitrous oxide, opiates, barbiturates, droperidol