Myasthenia Gravis

Question 1

Neuromuscular disorder caused by a decrease in the number of available acetylcholine receptors

Answer 1

Myasthenia Gravis

Question 2

Acetylcholine is synthesized in the _______ nerve terminal and stored in________

Answer 2

motor, vesicles (quanta)

Question 3

Acetylcholine combines with the binding sites on the _____ subunits of the acetylcholine receptors

Answer 3

alpha

Question 4

Acetylcholine receptor opens and permits the entry of _______ cations which produces depolarization

Answer 4

sodium

Question 5

(TRUE or FALSE) Depolarization happens on the end-plate region of the muscle fiber

Answer 5

TRUE

Question 6

Acetylcholine is hydrolyzed by ________ which terminates muscle contraction

Answer 6

acetylcholinesterase

Question 7

In myasthenia gravis, the postsynaptic folds are __________

Answer 7

flattened or simplified

Question 8

______________ is the amount of ACh released per impulse that normally decreases on repeated activity

Answer 8

Presynaptic rundown

Question 9

MG is an autoimmune disorder most commonly caused by ___________

Answer 9

anti-AChR antibodies

Question 10

Muscles commonly chosen in muscle biopsy are ______, _______, and ________

Answer 10

deltoid, biceps, and quadriceps

Question 11

(men, women) are frequently affected in myasthenia gravis

Answer 11

women

Question 12

Protein in NMJ which is involved in AChR clustering with reduction of AChRs

Answer 12

muscle-specific kinase (MuSK)

Question 13

Low-density protein that is important in clustering of AChRs which is present in 1-3% of MG patients

Answer 13

lipoprotein receptor-related protein 4 (LRP4)

Question 14

Class of MG which manifests as any ocular muscle weakness while all other muscles groups are normal

Answer 14

Class I

Question 15

Class of MG which is characterized by moderate weakness of muscles other than ocular muscles that involves mostly oropharyngeal, respiratory muscles or both

Answer 15

Class IIIb

Question 16

Class IVa MG is characterized by severe muscles weakness other than ocular muscles that involves mostly _____, _______, or both

Answer 16

limb, axial muscles

Question 17

Bulbar weakness is seen mainly in _____________ positive MG

Answer 17

MuSK-antibody

Question 18

The pathogenic antibodies in MG are _________ and __________ dependent

Answer 18

IgG, T cell

Question 19

Cardinal features of myasthenia gravis are ________ and ___________ of muscles

Answer 19

weakness, fatigability

Question 20

Common initial complaints of MG patients (2)

Answer 20

diplopia and ptosis

Question 21

(TRUE or FALSE) Limb weakness in MG is often proximal and may be symmetric

Answer 21

FALSE

Question 22

_____________ occurs when ventilatory weakness requires respiratory assistance

Answer 22

Myasthenia crisis

Question 23

Thymus is abnormal in ~75% of (AChR antibody positive, MuSK antibody positive, LRP4 antibody positive) myasthenia gravis

Answer 23

AChR antibody positive

Question 24

(TRUE or FALSE) Ocular MG is when the weakness is restricted to EOMs for 3 years is more likely to become generalized

Answer 24

FALSE

Question 25

A quick and easy diagnostic test for MG that can be done in the clinic or at the bedside of a hospitalized patient, which is due to less depletion of quanta of AChR in the cold and reduced activity of AChE at the NMJ

Answer 25

Ice-pack test

Question 26

_________ occurs when there is a combination of presynaptic rundown and decreased efficiency of neuromuscular transmission

Answer 26

Myasthenic fatigue

Question 27

___________ is an autoimmune disorder caused by antibodies that block ACh release by inhibiting a presynaptic calcium channel

Answer 27

Lambert-Eatan Myasthenic Syndrome

Question 28

_______ is a protein derived from motor nerves that normally binds to LRP4 and important for normal clustering of AChRs at NMJ

Answer 28

Agrin

Question 29

Antibodies directed against _______ receptors and ________ are associated in patients with thymoma and MG and neuromyotonia or Morvan syndrome

Answer 29

Netrin-1, Caspr2

Question 30

(TRUE or FALSE) In electrodiagnostic testing, myasthenic patients have a rapid reduction of >10% in amplitude of the evoked responses

Answer 30

TRUE

Question 31

Edrophonium is used to (treat/diagnose) MG because of its rapid onset (30s) and short duration (~5min) of its effect

Answer 31

diagnose

Question 32

Positive result in Tensilon test is diagnostic for MG who have negative ______, ________________ , or ________.

Answer 32

antibody, electrodiagnostic test, ice-pack test

Question 33

People with certain genetic markers called __________ are at risk of MG

Answer 33

HLA-B8, D3

Question 34

__________ patients typically do not experience myasthenic crisis, but are generally difficult to treat than _________ MG

Answer 34

Anti-MuSk, Anti-AChR

Question 35

__________ or _________ can cause exacerbation of weakness in myasthenic patients

Answer 35

Aminoglycoside antibiotics, procainamide

Question 36

Initial dose of ____ of Edrophonium is given, and thye result is said to be positive if definitive improvement occurs

Answer 36

2mg IV

Question 37

Common side effects of Edrophonium are nausea, diarrhea, salivation, fasciculation, syncope and bradycardia, so _______ is given when the symptoms of the side effects worsen

Answer 37

Atropine

Question 38

A synthetic quaternary amine that binds reversibly to the active center of AChE to prevent the hydrolysis of ACh

Answer 38

Edrophonium

Question 39

A synthetic quaternary amine that is a reversible AChE inhibitor that has greater effect on skeletal muscle and contraindications to patients with intestinal or urinary bladder obstruction

Answer 39

Neostigmine

Question 40

An intermediate-acting cholinesterase inhibitor that has a duration of 3-6hrs and is used in the management of chronic myasthenia gravis

Answer 40

Pyridostigmine

Question 41

Physostigmine is also called ________, a naturally occurring tertiary amine that acts as substrate for AChE

Answer 41

Eserine

Question 42

Intermediate-acting cholinesterase inhibitors such as neostigmine, pyridostigmine and physostigmine are called _________

Answer 42

Carbamates

Question 43

Muscle-like cells within the thymus

Answer 43

Myoid cells

Question 44

Treatment with _________ and ____ may be used before thymectomy to maximize strength in weak patients

Answer 44

plasmapheresis, IVIg

Question 45

It is the mechanical separation of plasma with blood cells that produces short-term reduction in AChR

Answer 45

plasmapheresis

Question 46

Prednisone is converted to _________ and alters the gene expression by binding to glucocorticoid receptors in the body

Answer 46

Prednisolone

Question 47

A csDMARD drug that inhibits the de novo synthesis of purine and inhibits the proliferation of lymphocytes

Answer 47

Mycophenolate Motefil

Question 48

It suppresses inosinic acid synthesis, B-cell and T-cell function, Ig production and IL-2 secretion, through its major metabolite 6-thioguanine

Answer 48

Azathioprine

Question 49

Calcineurin inhibitor that regulates gene transcription, inhibits IL-1 and IL-2 receptor productions, and macrophage-T cell interaction and T cell responsiveness

Answer 49

Cyclosporine

Question 50

Rituximab binds to the ____ molecule on B lymphocytes

Answer 50

CD20

Question 51

Chimeric monoclonal antibody that is more effective in MuSK antibody-positive MG

Answer 51

Rituximab

Question 52

csDMARD that is converted to Phosphoramide mustard (active form) which cross-links DNA to prevent cell replication

Answer 52

Cyclophosphamide

Question 53

Exacerbation of weakness sufficient to endanger life

Answer 53

Myasthenic crisis

Question 54

Treatment for myasthenic crisis include (give at least 2, there are 5 answers)

Answer 54

Antibiotics, ventilatory assistance, pulmonary physiotherapy, plasmapheresis, IVIg

Question 55

Weakness and fatigability of proximal or distal etemity muscles, EOMs and eyelids caused by genetic mutations

Answer 55

Non-autoimmune congenital myasthenia

Question 56

Symptoms include ptosis of the eyelids, diplopia, depressed or absent reflexes, dry mouth and impotence

Answer 56

Lambert-Eaton Myasthenic Syndrome (LEMS)

Question 57

LEMS is caused by autoantibodies directed against __________ calcium channels at the motor nerve terminals

Answer 57

P/Q-type

Question 58

In older adults, LEMS is associated with malignancy, most commonly ______________________

Answer 58

small-cell lung cancer (SCLC)

Question 59

Symptoms of Botulism (Give the 4 Ds)

Answer 59

Diplopia, Dysarthria, Dysphonia, Dysphagia

Question 60

Most common cause of botulism

Answer 60

ingestion of improperly prepared food containing toxin

Question 61

Historic name for myasthenia-like fatigue syndrome without organic basis

Answer 61

Neurasthenia

Question 62

Muscle testing in neurasthenia reveals that it is a ___________ which is a characteristic of nonorganic disorder or tiredness or apathy

Answer 62

"give-away weakness"

Question 63

Diplopia resembling in MG is due to an intracranial mass lesion that compresses nerves to the EOMs

Answer 63

Hyperthyroidism

Question 64

Weakness of the EOMs which may be accompanied by weakness of the proximal muscles of the limb and is associated with mitochondrial conditions

Answer 64

Progressive external opthalmoplegia

Question 65

Penicillamine induces the production of AChR antibodies

Answer 65

Drug-induced myasthenia

Question 66

Neoplastic change also called ______ may produce enlargement of the thymus

Answer 66

thymoma