Rare complication Flashcards
What is malignant hyperpyrexia
Life threatening condition resulting from a genetic sensitivity of skeletal muscles to volatile anaesthetics and depolaring muscle neuromuscular blocking drugs
What is the genetics for malignant hyperpyrexia
Autosomal dominant
With variable penetrance
Presentation of malignant hyperpyrexia
Muscular rigidity Hypermetabolic state Inc O2 consumption Inc CO2 production hyperthermia Rhabdomyolysis
Pathophysiology
Mutation in the ryanodine 1 receptor on sarcoplasmic reticulum - stored calcium
Normal muscle - small amount of Ca2+ released when triggered then reabsorbed into the SR for the next cycle
In MH the receptor doesn’t close properly after opening for a stimulus so the there is excess ca2+ release as they are being sequestered but just leak out leading muscle rigidity symptoms
This uses lots of ATP - hypermetabolic
Produced excess heat - hyperaemic
Muscle cells get damaged by depletion of ATP so that the contents leak —> rhabdomyolysis
K+ leak —> hyperkalaemia
Triggers for malignant hyperpyrexia
Halothane
Suxamethonium
Tx malignant hyperpyrexia
Help Hyperventilate the patient 100% O2 Finish or abort the procedure Cool patient Clean the breathing system Cause diuresis Treat hyperkalamia, dysrhythmias Monitor CK Monitor coagulation Administer DANTROLENE
Test for malignant hyperpyrexia
Muscle biopsy at a special centre
What is pseudo cholinesterase deficiency
Inherited enzyme abnormality
There is abnormally slow tabloid degradation of exogenous choilne ester drugs
So you get a pronged duration of sux or LA ester - procaine and Cocaine