MH Flashcards
MH mutation genes
RYR 1 chr 19
CACNA1S chr 1
STAC3 chr 12
Hypermetabolism: ATP needed for what 3 things
Ca release, reuptake into SR, and troponin decoupling
MH: succ vs VA causes cell level
Succ sustained depolarization at nAChR. VA at ryanodine receptor, ca release from SR
Earliest s/s MH
Hypercarbia, tachypnea, tachycardia
Confirmatory lab in kids w masseter spasm after sux
> 20,000 CPK
MMR: what is normal, check what, MH occurs how often
Mild inc masseter tone after sux w limb flaccidity. Check K and ABG. MH occurs in 20% of cases of MMR
3 symptoms that occur w rhabdo
Muscle pain, myoglobinuria, arrhythmias from high K
CPK correlates
In >20k well w rhabdo, less well w fever and acidosis
Rapid v slow rhabdo
K dangerously high/quick in rapid, in slow its safer, K is redistributed before blood levels increase
Sympathetic response leads to 3 things in heart/vessels
Inc catecholamines lead to inc HR, cutaneous vasoconstriction, inc SVR
Inc CO
What to do in isolated MMR
D/c volatiles, give propofol, turn up flows, get another IV/give vol/ABG. Observe 24h if other symptoms. Maybe muscle bx
Gold standard MH test
Halothane caffeine contracture test. Muscle in halothane, sustained contracture. 80% specificity
How dantrolene works, 1/2 time
Reduces muscle tone and metab. Dec release of Ca from SR. Blocks external entry of Ca into sarcoplasm. Inhib ca thru ryanodine receptors. 10-15 e 1/2
Dantrolene: doesnt potentiate effects of what
Non depolarizing muscle relaxants or interfere w reversal. Can cause weakness if pre existing NM disease
DONT use dantrolene with what
CCB, life threatening hyperkalemia and myo depression
How many vials need to be in facility if sux is used, what else needs to be there
36 minimum. Sterile water, 60 ml/vial
Dantrolene dosage
2.5 mg/kg bolus, then maintenance dose 2 mg.kg q 5 min. Total 10 mg/kg. Then 1 mg/kg q6 for 72 hours
Where we want temp. Saline bolus dose.
38 c. 15 ml/kg q 10 min
Hyperkalemia treatment
1 ml/kg d50 glucose and 0.15 u/kg regular insulin and/or CaCl 5-10 mg/kg IV
Monitoring how long after, recrudescence how often. Avoid what, measure what
36h in icu. 25%. No LR (K). Coag profile for DIC and CKs q6h
Lab supplies needed
6 abg kits, Ck myoglobin, sma 19, pt/ptt, fibrinogen, fsps, CBC, LA level. Urine myoglobin level x2, urine dipstick hgb
Muscle diseases assoc w MH 3
Not assoc w which one
Central core disease, king denborough syndrome, and Evans myopathy. Not: MD but can still develop rhabdo so still avoid triggering agents
Neuroleptic malignant syndrome presentation. Who is susceptible
Fever, muscle rigidity, ANS instab, delirium, elev CPK. Pts on haldol, prolixin, thorazine
Sudden cardiac arrest after sux in young males can be what
R/t hyperkalemia in undx myopathy. 50% mortality rate, may also have rigidity and hyperthermia
Meds/tx for sudden unexpected cardiac arrest
Ca cl, hco3, insulin, glucose, hyperventilation. May need dialysis and CPB
Report MH to who
North American mh registry. In CHOP in Pittsburgh. Barbara Brandon
