Flashcards in malignant hyperthermia Deck (18):
What is Malignant Hyperthermia?
MH is an autosomally dominant disorder of skeletal muscles.
Calcium that’s stored in skeletal muscle is released inappropriately causing muscles to contract & stiffen simultaneously. extensor stronger than flexor. go into extension during seizure
his faulty metabolism causes dangerous
hyperthermia, skeletal muscle breakdown (rhabodmyolysis), run-away hypermetabolism, acidosis, flushed skin, myoglobinuria (what’s this?) oxygen store in muscle, hypotension, and death
Symptoms of malignant hyperthermia
typically appear within one hour (but can be delayed up to ~12 hours)
Most cases occur in children and young adults <30 years old
Known chemical MH triggers
isoflurane,sevoflurane, desflurane, anectine
not MH triggers
-Intravenous anesthetics (including Propofol) -Opiates -Non-depolarizing muscle relaxants -Ketamine
-Sedatives and Tranquilizers.
Reports vary from 1:5000-1:100,000 anesthetic procedures
Occurs in all races & ethnicities`
International mortality data on MH ranges from 1.4%- 20.0% which appears to be based entirely on the speed of MH diagnosis and therapy initiation!
Median age in cases of U.S. deaths
20 yrs. A “muscular build” was identified as having a high predictive
value for increased morbidity and mortality
Again, retrospective analysis identified preparedness by the medical team as a major positive prognostic indicator. time is trauma
Clinical Signs of MH
Dramatically increase CO2 production
Rhabdomyolysis Profound hyperthermia
clinical signs of MH Non-Specific
Tachypnea Acidosis (both respiratory &
(most common): muscular rigidity, extreme hyperthermia, tachycardia. Typically occurs shortly after anesthetic induction
Masseter Muscle Rigidity (MMR):
profound jaw muscle rigidity after succinylcholine administration; may be an early sign of MH
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 25-30% chance of having Fulminant MH during their next anesthetic!
Other prognostic indicators
Patients with muscular disorders such as muscular dystrophy, various “myotonias”, Duchenne’s Disease, Becker’s Disease, etc. are at much greater risk of Fulminant MH and shouldn’t receive succinylcholine
Why does MH occur?
A mutation in the ryanodine receptor gene (RYR1) in skeletal muscles affects the muscles’ ability to properly utilize calcium.
Treatment of acute MH. KNOW!!!!!!!!!!!!!
Immediately discontinue volatile gas anesthetics and succinylcholine administration
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
Treat arrhythmias but DO NOT GIVE CALCIUM CHANNEL BLOCKERS!!!
Monitor coagulation and electrolytes (why?) acidosis and K will be hyped up