Topic 21: Malignant Hyperthermia Flashcards
What kind of disorder is MH?
autosomally dominant disorder of skeletal muscles.
Calcium that’s stored in skeletal muscle is released inappropriately causing muscles to contract & stiffen simultaneously
When Ca that is stored in skeletal muscle is released – causing muscles to contract and stiffen – what Dangerous/Negative things can happen?
This faulty metabolism causes dangerous
hyperthermia, skeletal muscle breakdown (rhabodmyolysis), run-away hypermetabolism, acidosis, flushed skin, myoglobinuria (what’s this?), hypotension, and death
When do symptoms of malignant hyperthermia typically appear ?
within one hour (but can be delayed up to ~12 hours)
What age range is most cases of MH?
children and young adults - <30yo
Median age in cases of U.S. deaths was 20 years
A “muscular build” was identified as having a high predictive value for increased morbidity and mortality
Known chemical triggers of MH? (4)
Forane, Sevoflurane, Supranem Anectine
NOT chem triggers of MH?
Intravenous anesthetics Opiates non-depolarizing muscle relaxants Ketamin sedatives and tranquilizers
International mortality data on MH ranges %%? based on what??!!
1.4%-20.0% which appears to be based entirely on the speed of MH diagnosis and therapy initiation! !!
Clinical Signs of MH - Specific (4)
Muscle Rigidity
Dramatically CO2 production
Rhabdomyolysis
Profound hyperthermia
Clinical Signs of MH - NonSpecific (4)
Tachycardia
Tachypnea
Acidosis (both respiratory & metabolic)
Hyperkalemia
Masseter Muscle Rigidity (MMR):
profound jaw muscle rigidity after succinylcholine administration; may be an early sign of MH
MMR
Masseter Muscle Rigidity
Fulminant MH:
(most common): muscular rigidity, extreme hyperthermia, tachycardia. Typically occurs shortly after anesthetic induction
Late Onset MH:
(uncommon): Occurs within the first hour of anesthetic termination
MMR prognostic indicator
Patients with a history of MMR post-anesthetic induction have a ___ chance of having _____ during their next anesthetic!
25-30%
Fulminant MH
KNOW
Why does MH occur? mutation in what??????
A mutation in the ryanodine receptor gene (RYR1) in skeletal muscles affects the muscles’ ability to properly utilize calcium.
Treatment of MH- DANTROLENE DOSE???
Give Dantrolene at a dose of 2.5mg/kg IV push and repeat PRN
Treatment of MH - what do you do with arrhythmias?
Treat arrhythmias but DO NOT GIVE CALCIUM CHANNEL BLOCKERS!!!
Treatment of MH – what to do with the gas situation?
Immediately discontinue volatile gas anesthetics and succinylcholine administration
Hyperventilate with 100% oxygen (+/ -change out gas tubing)
Treatment of MH – What drugs do you give??
Give 1-2 mg/kg bicarbonate
Give Dantrolene at a dose of 2.5mg/kg IV push and repeat PRN
Treatment of MH - Temp of patient ?
monitor what?
Cool Patient
Monitor coagulation and electrolytes
Dantrolene — how does it work????
(Dantrium)
blocks the release of calcium from skeletal muscle’s sarcoplasmic reticulum which prevents the pathologically massive, prolonged release of calcium through the RYR1 channels which is the etiology of Fulminant MH
Malignant Hyperthermia – WIKIPEDIA definition
Malignant hyperthermia (MH) or malignant hyperpyrexia[1] is a rare life-threatening condition that is usually triggered by exposure to certain drugs used for general anesthesia, specifically the volatile anesthetic agents and the neuromuscular blocking agent, succinylcholine. In susceptible individuals, these drugs can induce a drastic and uncontrolled increase in skeletal muscle oxidative metabolism, which overwhelms the body’s capacity to supply oxygen, remove carbon dioxide, and regulate body temperature, eventually leading to circulatory collapse and death if not treated quickly.
