Musculoskeletal diseases 2 Flashcards
Which agents are safe to administer to the patient with hypokalemic periodic paralysis?
a. rocuronium
b. terbutaline
c. D5LR
d. acetazolamide
a. rocuronium
d. acetazolamide
Familial periodic paralysis is characterized by
acute episodes of skeletal muscle weakness accompanied by serum potassium concentration changes
two variants of the disease- hypokalemic & hyperkalemic
Hypokalemic periodic paralysis is presnt if
skeletal muscle weakness follows a glucose-insulin infusion
With hypokalemic periodic paralysis, the patient becomes weak when the serum K+
decreases
Hyperkalemic periodic paralysis is present if skeletal muscle weakness follows
oral potassium administration
The patient with hyperkalemic periodic paralysis becomes weak when
serum K+ increases
_______ is the treatment for both forms of familial periodic paralysis
Acetazolamide
For patients with familial periodic paralysis, _______ should be avoided at all costs.
Hypothermia
For patients with hyperkalemic familial periodic paralysis, __________ is contraindicated.
succinylcholine
For patients with hypokalemic familial periodic paralysis ________________ should be avoided because _______
succinylcholine because this condition might be associated with MH
_______ should be monitored for patients with familial periodic paralysis.
Serum potassium levels
Familial periodic paralysis is a disorder of ____________ and not a disease of ____________
the skeletal muscle membrane (reduced excitability) and not a disease of the neuromuscular junction
Hypokalemic periodic paralysis is associated with a _______ channelopathy
calcium
Hyperkalemic periodic paralysis is associated with a _________ channelopathy
sodium
Why is acetazolamide the treatment of choice for both forms of familial periodic paralysis?
it creates a non-anion acidosis which protects against hypokalemia and it also facilitates renal potassium excretion which guards against hyperkalemia
For patients with hypokalemic periodic paralysis, we should avoid these drugs:
glucose containing solutions
potassium wasting diuretics
beta-2 agonists
succinylcholine
For patients with hyperkalemic periodic paralysis, we should avoid these drugs:
succinylcholine
potassium containing solutions (LR)
Malignant hyperthermia is primarily associated with the genetic mutation of the:
a. SERCA2 pump
b. ryanodine receptor
c. dihydropyridine receptor
d. actin myofilament
b. ryanodine receptor
List three co-existing diseases that are definitely associated with MH:
King-Denborough syndrome
Central core disease
multiminicore disease
What two classes of drugs are known to trigger MH?
halogenated anesthetics
depolarizing neuromuscular blockers
MH is an
inherited disease of skeletal muscle that is characterized by disorder calcium homeostasis
Describe the pathophysiology of MH.
a defective ryanodine receptor contributes to excessive Ca2+ release from the endoplasmic reticulum and this leads to sustained skeletal muscle contraction, a hypermetabolic state, and increased oxygen consumption
MH is not associated with the following conditions:
Duchenne muscular dystrophy
Becker muscular dystrophy
neuroleptic malignant syndrome
myotonia congenita
myotonic dystrophy
osteogenesis imperfecta
Consequences of increased intracellular calcium in the myocyte include
rigidity from sustained contraction
accelerated metabolic rate and rapid depletion of ATP
increased oxygen consumption
increased CO2 and heat production
mixed respiratory and lactic acidosis
sarcolemma breaks down
potassium and myoglobin leak into the systemic circulation
Factors that increase the risk of MH include
Male sex
youth
geography- families from Wisconsin, Nebraska, West Virginia, and Michigan appear to be at higher risk
The earliest signs of malignant hyperthermia include (choose 3):
a. tachycardia
b. hyperthermia
c. cola-colored urine
d. increased EtCo2
e. masseter spasm
f. DIC
a. tachycardia
d. increased EtCo2
e. masseter spasm
The most sensitive indicator of MH is
EtCO2 that rises out of proportion to minute ventilation
MH can occur as late as ______ hours after exposure to a triggering agent
6 hours
____________ is typically a late sign of MH.
hyperthermia
Conditions to consider in your differential diagnosis of MH includes
thyroid storm
pheochromocytoma
sepsis
heatstroke
_____ & _______ are two entities that exist on a continuum with MH.
Trismus and masseter muscle rigidity
_____ describes a tight jaw that can still be opened and is a normal response to __________
trismus; succinylcholine
_____________ muscle rigidity describes a tight jaw that cannot be opened. ____________ will not relax the jaw.
Masseter muscle rigidity; a neuromuscular blocker
Anyone who has experienced MH or masseter spasm should be referred for
a halothane contracture test for diagnosis
Early signs of MH include
tachycardia
tachypnea
masseter spasm
warm soda lime
irregular heart rhythm
Intermediate signs of MH include
cyanosis
irregular heart rhythm
patient warm to touch
Late signs of MH include
muscle rigidity
cola-colored urine
coagulopathy
irregular heart rhythm
overt hyperthermia
What drug is contraindicated in the management of malignant hyperthermia?
a. verapamil
b. mannitol
c. calcium chloride
d. insulin
a. verapamil
CCB can result in life-threatening hyperkalemia
Considerations for preventing MH include:
flushing the anesthesia machine with high flow oxygen for up to 100 minutes
the vaporizers must be physically removed from the machine
external parts should be removed and replaced (CO2 absorbent, circuit, and breathing bag)
dantrolene prophylaxis is unwarranted
The four steps to treat MH include.
Discontinue the triggering agents. Convert to an IV technique.
call for help and notify the surgeon to terminate the procedure
hyperventilate with 100% O2 at a minimum FGF of 10L/min
apply charcoal filters to the inspiratory and expiratory port and then apply a new breathing circuit and bag
The last 4 steps of treating MH include
administer dantrolene or Ryanodex 2.5 mg/kg IV q5-10 mint
cool the patient
treat acidosis and electrolyte disturbances
maintain UO above 2mL/kg/hr
If the patient with MH doesn’t present with s/sx of MH within the first _________ of the procedure, then it is very unlikely that it will occur later.
hour
As an alternative to the purging guidelines (10L FGF at 100% O2 for min 20-100 min.), you can use
a charcoal filter such as the Vapor-clean
flush with high FGF for 90 seconds prior to using the machine on the patient
After the patient is stabilized, they should be
observed in the ICU as MH can reoccur up to 36 hours
What are the MOAs of dantrolene?
it reduces Ca2+ release from the RyR1 receptor in the skeletal myocyte
it prevents Ca2+ entry into the myocyte which reduces the stimulus for calcium-induced calcium release
What should dantrolene be reconstituted with?
60 mL of preservative free water
NS introduces additional solute and prolongs the time required for dantrolene to dissolve
Most common side effects of dantrolene are
weakness
venous irritation
What is the continuous infusion rate of dantrolene?
1 mg/kg q6 hr. or 0.1-0.3 mg/kg/hr for 48-72 hours
If the patient requires more than ___________, reconsider the diagnosis of MH
20 mg/kg
Patients with MH should be cooled until
their temperature drops below 38 degrees C
Ways to cool the patient include
Cold IVF
cold fluid lavage of stomach and bladder
ice packs
What can be given to correct lactic acidosis?
sodium bicarbonate 1-2 mEq/kg IV titrated to ABG and base deficit
What can be done to treat hyperkalemia?
CaCl 5-10 mg/kg IV
insulin 0.15 units/kg + D50 1 mL/kg
Hyperventilation
What can be given to protect against dysrhythmias for the patient with MH?
procainamide 15 mg/kg IV
lidocaine 2 mg/kg IV
co-administration of a CCB with dantrolene can precipitate life-threatening hyperkalemia
For patients with MH, urine output can be maintained with
IV hydration
mannitol 0.25 g/kg IV
furosemide 1 mg/kg IV
