neuro 24 Flashcards Preview

Neuro > neuro 24 > Flashcards

Flashcards in neuro 24 Deck (75)
Loading flashcards...
1
Q

defining feautres of NMJ syndromes

A

fatiguable muscle weakness

2
Q

myasthenia gravis

A

antibodies to the post-synaptic nicotinic Ach receptor; this leads to complement-mediated attack and internalization of the receptors

3
Q

most common clinical manifestations of MG

A

ocular involvement is most common, manifesting as ptosis and diplopia; bulbar muscle weakness; limb weakness is usually proximal and symm; DTRs preserved

4
Q

myasthenic crisis

A

presentation of MG with respiratory muscle weakness; medical emergency; must obtain FVC and neg inspir force

5
Q

cholinergic crisis

A

state of increased cholinergic drive due to overmed with choliesterase inhib; also characterized by the presence of increased bronchial secretions, salivation, diarrhea, n/v, and diaphoresis

6
Q

diagnostic eval of MG

A

edrophonium chloride (Tensilon) is an anti-Ach administered IV and the patient is observed for improvement in muscle strength; antibodies against nAChR

7
Q

antibodies directed against MuSK and Lpr4

A

may be present in some patients with MG

8
Q

repetitive nerve stim

A

reveals a decremental response that is seen in MG

9
Q

Single fiber electromyography

A

most sens clinical test of NM transmission; characteristic finding in MG is increased jitter (a measure of the variability of NM transmission)

10
Q

treatment for MG

A

anti-acetylcholinesterase drugs like pyridostigmine; immune modulating therapy; plasmapharesis and IVIg, steroids; thymectomy

11
Q

Lambert-Eaton myasthenic syndrome

A

usually assoc with small cell lung cancer; caused by antibodies to presynaptic voltage-gated calcium channels

12
Q

clinical presentation of lambert-eatin myasthenic syndrome

A

fatigable proximal weakness; DTRs are reduced or absent;

13
Q

what is major difference bt Lambert-Eaton and MG?

A

bulbar and ocular sx are rare in LE, but autonomic complaints are common (dry eyes, dry mouth, impotence);

14
Q

characteristic finding in LE

A

muscle faciliation (with brieg intense exercise, muscle strength increases and reflexes may appear transiently)

15
Q

diagnosis of LE

A

antibodies to anti-voltage-gated calcium channel; decremental response on slow repeititive nerve stim and an incremental response on fast repetitive nerve stimulation helps to establish the diagnosis

16
Q

treatment for LE

A

initial therapy is directed at underlying malignancy which is usually present in LE; when no malignancy is found, use steroids, azathioprine, IVIg, and plasmapheresis

17
Q

most effective treatment in LE

A

3,4-diaminopyridine (and may be more effective if used together with pyridostigmine)

18
Q

muscle biopsy in DMD and BMD

A

decreased staining for dystrophin

19
Q

treatment for DMD and BMD

A

glucocorticoids slows the decline in musle strength

20
Q

most frequent genetic cause of limb girdle muscular dystrophies

A

mutations in calpain-3 or sarcoglycans

21
Q

limb girdle muscular dystrophies

A

shoulder and hip girdle weakness with relative sparing of extraocular, pharyngeal, and facial muscles

22
Q

myotonic dystrophy genetics

A

either unstable CTG expansion in the DMPK gene or a CCTG expansion in the ZNF9 gene; disordered RNA processing

23
Q

clinical features of myotonic dystrophy

A

weakness and stiffness of distal muscles; proximal develops later; systemic findings like cataracts, ptosis, arrhythmias, dysphagia (esoph myotonia); neurobehavioral features

24
Q

important treatment in myotonic dystrophy

A

cardiac pacing; drugs like mexilitine, phenytoin, and carbamazepine may reduce the myotonia

25
Q

most common adult onset muscular dystrophy

A

myotonic dystophy

26
Q

fascioscapulohumeral muscular dystrophy

A

aut dom; weakness in face, scapula, and humerus; asymmetric weakness; over time, it descends;heart is usually spared

27
Q

diagnosis of facioscapulohumeral muscular dystrophy

A

genetic testing. Deletion of D4Z4 repeat on 4q35

28
Q

Emery-Dreifuss muscular dystrophy

A

mutations in emerin getne on the X chrom; or mutations in the lamin A and lamin C genes on chrom 1

29
Q

clinical characteristics of Emery-Dreifuss muscular dystrophy

A

early onset of joint contractures, slowly progressive humeroperoneal pattern of weakness and atrophy, and cardiomyopathy that manifests as conduction abnormalities

30
Q

what does humeroperoneal mean?

A

affects the bicepts, triceps, peroneal, and tibial muscles

31
Q

female carriers of emery-dreifuss muscular dystrophy

A

do not develop weakness or atrophy but are at risk for cardiac complications

32
Q

diagnosis of emery-dreifuss

A

CK levels mildly to moderatley elevated, EMG is myopathic, and muscle biopsy shows nonspec dystrophic changes

33
Q

staining in emery-dreifuss

A

reduced or absent immunostaining fro emerin;

34
Q

treatment for emery-dreif

A

none really; range of motion and stretching exercises may help with contractures; pacemakers for patients w severe conduciton abnormalities

35
Q

Periodic Paralyses

A

characterized by episodic muscle weakness

36
Q

cause of periodic paralyses

A

mutations in skeletal muscle membrane ion channel; attacks usually associated with a change in serum potassium

37
Q

examples of mitochondrial myopathies

A

myoclonic epilepsy with ragged red fibers (MERRF); mitochondiral myopathy encephalopathy, lactoacidosis, and stroke (MELAS); progressive external ophthalmoplegia (PEO); and the Kearns-Sayre syndrome

38
Q

findings in mitochondrial myopathies

A

co-occurrence of a myopathy and a peripheral neuropathy; serum lactate and pyruvate are often increased

39
Q

examples of immune-mediated inflamm myopathies

A

polymyositis, dermatomyositis, and inclusion body myositis

40
Q

clinical findings in polymyositis and dermatomyositis

A

proximal (usually symm) muscle weakness

41
Q

clinical presentation of inclusion body myositis

A

weakness is asymm; may affect both prox and distal muscles; early selective involvement of forearm and finger flexors, as well as of knee extensors (quads)

42
Q

how is IBM often diagnosed

A

when patients thought to have PM fail to respond to steroids

43
Q

purplish discoloration of the eyelides (heliotrope) and papular erythematous scaly lesions over the knuckles (Gottron patches)

A

characteristc of dermatomyositis

44
Q

other features of DM

A

cardiac manifestations, interstitial lund disease

45
Q

anti-Jo-1 antibodies

A

seen in patients with dermatomyositis that have interstitial lung disease

46
Q

which of the inflamm myopathies is most commonly assoc with other autoimmune diseases

A

polymyositis

47
Q

pathogenesis of dermatomyositis

A

antibodies and complement against intramuscular blood vessels; inflamm is due to muscle ischemia

48
Q

pathogenesis of polymyositis

A

mediated by CD8 T cells

49
Q

pathogenesis of inclusion body myositis

A

both inflamm and neurodegenerative disorder

50
Q

diagnosis of inflamm myopathies

A

CK elevated; EMG shows myopathic changes

51
Q

diagnosis of PM on biopsy

A

endomysial inflamm with invasion of nonnecrotic muscle fibers with CD8+ T cells

52
Q

diagnosis of IBM on muscle biopsy

A

endomysial inflamm and basophilic rimmed vacuoles

53
Q

treatment for PD, DM, and IBM

A

steroids for PM and DM but they don’t help in IBM; IVIg helpful in DM

54
Q

thyrotoxic myopathy

A

proximal muscle weakness and atropy with normal or brisk relexes; bulbar and resp muscle involvement is uncommon;

55
Q

pathogenesis of thyrotoxic myopathy

A

unknown, but may reflect enhanced muscle catabolism

56
Q

how to treat thyrotoxic myopathy

A

treat underlying thyrotoxic state with beta blockers to improve muscle strength

57
Q

hypothyroid myopathy

A

prox muscle weakness, fatigue, myalgias, and cramps; reflexes may demonstrate delayed relaxation; CK typically elevated; may be associated distal polyneropathy

58
Q

steroid myopathy

A

increased glucocorticoids from endogenous production or exogenous adminsitration; risk reduced with alternate-day regimens;

59
Q

symptoms in steroid myopathy

A

weakness is predominantly proximal, with sparing of ocular, bulbar, and facial muscles

60
Q

steroid myopathy muscle biopsy demonstrates what

A

type II fiber atrophy, but this finding is nonspec

61
Q

drug or toxin induced myopathy

A

proximal myopathy and increased serum CK level

62
Q

CK level in the metabolic myopathies

A

typically normal except elevated in hypothyroidism

63
Q

neuroleptic malignant syndrome

A

syndrome characterized by fever, depressed level of arousal, muscle rigidity, and autonomic dysfunction

64
Q

what usually causes neuroleptic malignant syndrome?

A

treatment with antipsychotics (haloperidol etc) but may also occur with L-dopa withdrawal in patients with parkinsons and in assoc with TCAs

65
Q

etiology of neuroleptic malignant syndrome

A

central dopaminergic blockade

66
Q

treatment of neuroleptic malignant syndrome

A

discontinue offending drup, aggressive fluid resus and other supportive measures, usually in an ICU; IV benzos may be helpful

67
Q

what is the drug that causes necrotizing myopathy?

A

HMG-CoA reductase inhib, cyclosporine, propofol, alcohol

68
Q

steroid myopathy caused by what

A

fluorinated glucocorticoids

69
Q

drug that causes mitochondiral myopathy

A

ZDV

70
Q

drug that causes inflamm myopathy

A

cimetidine, procainamide, L-dopa, phenytoin, lamotrigine, D-penicillamine

71
Q

drug that causes critical illness myopathy

A

corticosteroids plus neuromuscular blocking agents in patients with sepsis

72
Q

nerve stimulation in LE

A

decremental response following slow repetitive nerve stimulation and an incremental response following

73
Q

nerve stimulation in MG

A

decremental response following slow RNS

74
Q

MG with elevated anti-MuSK antibodies

A

typically less than 40 yo African American; present w early respiratory dysfunction and often do not respond to cholinesterase inhib like pyridostigmine

75
Q

why would you get a chest CT in a patient wth MG?

A

thymoma and thymic hyperplasia assoc with anti-AchR antibody MG