Neuromuscular

Question 1

Myasthenia Gravis is autoimmune destruction of what subunit of the muscle type nicotinic acetylcholine receptor?

Answer 1

Alpha subunit

Question 2

What muscles are affected by myasthenia gravis?

Answer 2

Ocular and bulbar (laryngeal and pharyngeal) .. skeletal muscles innervated by cranial nerves most vulnerable

Question 3

What is the Tensilon test?

Answer 3

Edrophonium test differentiates cholinergic crisis - need less pyridostigmine – muscle weakness with administration from myasthenic crisis – muscle strengthens with administration - need more pyridostigmine

Question 4

Depolarizing vs Nondepolarizing NMBAs for myasthenia gravis

Answer 4

Resistance to succ, very sensitive to nondepolarizing, use cisatracurium if necessary

Question 5

Greatest risk for postoperative respiratory failure with myasthenia gravis (5 items)

Answer 5

Duration of diagnosis over 6 years, concomitant pulmonary disease, PIP 750 mg/day, vital capacity

Question 6

Lambert-Eaton Myasthenic Syndrome is what?

Answer 6

Autoimmune destruction of presynaptic voltage-gated calcium channels at nerve terminal - reduced ACh at motor-end plate

Question 7

What muscles are affected by Lambert-Eaton myasthenic syndrome?

Answer 7

Originates in lower extremities and spreads upward

Question 8

Depolarizing vs nondepolarizing NMBAs for Lambert-Eaton myasthenic syndrome

Answer 8

Sensitive to both, avoid – less response to anticholinesterases

Question 9

Duchenne’s muscular dystrophy pathophysiology

Answer 9

Failure to code and produce dystrophin, fat starts to grow in areas where muscle cannot regrow

Question 10

Depolarizing vs nondepolarizing NMBAs for Duchenne’s muscular dystrophy

Answer 10

AVOID SUCC– risk for rhabdomyolysis – causing massive hyperK = hypermetabolism and cardiac arrest, longer than normal recovery time for non-depolarizing

Question 11

Rhabdomyolysis vs MH

Answer 11

Rhabdo will have really red urine output quickly - happens later with MH

Question 12

CPK levels and Duchenne’s muscular dystrophy

Answer 12

Will be elevated in early disease - some muscle disease, late disease will have lower levels due to muscle loss

Question 13

Myotonic dystrophy- steinerts

Answer 13

Repeats cytosine, thymine and guanine with severity related to number of extra trinucleotide repeats - extra Ca2+ availability.

Question 14

Depolarizing vs nondepolarizing and myotonic dystrophy

Answer 14

SUCC CONTRAINDICATED - would have repeated fasciculations. Cisatracurium ND-NMBA of choice- normal to prolonged DOA, AVOID reversal (aggravates myotonia). Peripheral nerve stimulator likely inaccurate

Question 15

Triad of myotonic dystrophy

Answer 15

Mental retardation, frontal baldness in males, presenile cataracts

Question 16

Treatment of severe myotonia

Answer 16

IV phenytoin, IM quinine, or IM procaine

Question 17

Demerol and myotonic dystrophy

Answer 17

Use it! Shivering induces myotonia, increases oxygen consumption– avoid hypothermia

Question 18

Glucose-6-phosphatase deficiency is?

Answer 18

Impaired glycogenolysis, causes repetitive fasting hypoglycemia, lactic acidosis, lipotoxicity.

Question 19

Anesthesia considerations with Glucose-6-phosphatase deficiency

Answer 19

AVOID LR (unable to convert lactic acid to glycogen), monitor glucose

Question 20

Acid Maltase Deficiency (Pompe’s disease) - is and anesthetic consideration?

Answer 20

Rapidly progressive weakness and enlargement of tongue, heart and liver– propofol may cause reduction in afterload precipitating MI

Question 21

Hypokalemic periodic paralysis is?

Answer 21

Defect in VGCa channels - decreases potassium = prevention of action potential

Question 22

Hyperkalemic periodic paralysis is?

Answer 22

Defect in VGNaChannels - prevents generation of AP.

Question 23

Malignant hyperthermia is?

Answer 23

Mutation of ryanodine receptor of many different genes (mostly 19)- uncontrolled release of Ca removes inhibition of troponin and increases ATP activity.

Question 24

Which patients are at increased risk for MH?

Answer 24

Duchenne’s MD, central core disease, osteogenesis imperfecta, king-denborough syndrome, ortho joint-dislocation repair, opthalmic ptosis and strabismus, ENT cleft palate, T and A, dental, family history, intolerance to caffeine, unexplained fevers/muscle cramps, trismus with induction, baseline CK chronically elevated, positive halothane-caffeine contracture test

Question 25

What medications to avoid with autonomic dysfunction?

Answer 25

Indirect acting pressors (ephedrine)

Question 26

Guillain-Barre syndrome and hemodynamic response with anesthesia

Answer 26

Autonomic dysfunction creates wide fluctuations in BP with absent cardiac compensation to PEEP, blood loss and postural changes

Question 27

Regional anesthesia and autonomic dysfunction

Answer 27

Putting numbing medications on nerves that are already struggling is a bad idea

Question 28

Charcot-Marie-Tooth syndrome and depolarizing vs nondepolarizing medications

Answer 28

Sensitive to ND and reduced response to Succ with increased risk for exaggerated hyperkalemic resopnse

Question 29

Upper motor neuron disease - where is the damage located?

Answer 29

Frontal cortex or tracts

Question 30

Lower motor neuron disease - where is the damage located

Answer 30

Ventral horn of spinal cord - NO SUCC

Question 31

Multiple sclerosis and regional type best used, temperature related anesthesia considerations

Answer 31

avoid spinal, ok for epidural, and increase by 0.5 degree may block conduction across demyelinated axons

Question 32

Benadryl and parkinson’s disease

Answer 32

Increases muscle tension and tremor

Question 33

Parkinson’s disease treatment aims

Answer 33

Increasing concentration of dopamine or decreasing neuronal effects of ACh

Question 34

Side effects of LevoDopa

Answer 34

Orthostatic hypotension (catecholamine deplation) and N/V (dopamine stimulating medullary CRTZ)

Question 35

Alzheimer’s disease treatment

Answer 35

cholinesterase inhibitors slow deterioration of mental status (tacrine, donepezil, galantamine, rivastigmine)– prolong succ, resistance to nondepolarizers

Question 36

Postpolio syndrome main anesthesia consideration

Answer 36

Extreme sensitivity to anesthesia drugs with delayed awakening due to poliovirus damage to RAS

Question 37

Neurofibromastosis main anesthesia concerns

Answer 37

Consider potential for pheo, tumors are highly vascular - be prepared for blood loss