Malignant Hyperthermia Flashcards
Effects of malignant hyperthermia
Hyperthermia Skeletal muscle breakdown (rhabdomyolysis) Run away hyper metabolism Acidosis Flushed skin Myoglobinuria Hypotension Death
MOA of malignant hyperthermia
Calcium that’s stored in skeletal muscles is released inappropriately causing muscles to contract and stiffen simultaneously
Known chemical MH triggers
Volatile gas anesthetics and SUX
International mortality data on MH
1.4-20%
Depends entirely on speed of diagnosis and treatment
Specific clinical signs of MH
Muscle rigidity
Dramatic increase in CO2 production
Rhabdomyolysis
Profound hyperthermia
Nonspecific clinical signs of MH
Tachycardia
Tachypnea
Acidosis
Hyperkalemia
Fulminant MH
Most common
Muscular rigidity, extreme hyperthermia, tachycardia
Occurs shortly after anesthetic induction
Masseter muscle rigidity (MMR)
Profound jaw muscle rigidity after SUX
Early sign of MH
Late onset of MH
Uncommon
Within first hour of anesthetic termination
Patients with a history of MMR post anesthetic induction have….
A 25-30% chance of Fulminant MH during their next anesthetic
Risk factors for Fulminant MH (shouldn’t be given SUX)
Muscular dystrophy
Myotonias
Duschennes disease
Beckers disease
How does MH occur?
Mutation in the ryanodine receptor gene (RYR1) in skeletal muscles affects it’s proper use of calcium
treatment of acute MH** (have to write on final)
- Immediately discontinue volatile gas anesthetics and SUX
- Hyperventilate with 100% oxygen (+/- change out gas tubing)
- Give 1-2 mg/kg bicarbonate
- Give Dantrolene at a dose of 2.5mg/kg IV push and repeat as needed
- Cool patient
- Treat arrhythmias but DO NOT GIVE CALCIUM CHANNEL BLOCKERS
- Monitor coagulation and electrolytes
MOA of Dantrolene (Dantrium)
Blocks release of Calcium from skeletal muscles SR which prevents the massive prolonged release of Ca through the RYR1 channels (etiology of Fulminant MH)
Dantrolene
Dantrium
