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Flashcards in EM Neuro Deck (64):
1

What's the most sensitive NCS?

Sensory NCS, on the sural nerve

2

On EMG, fibrillation potential, or positive sharp waves, are a clear sign of?

Denervation

3

On EMG, prolonged, polyphasic, increased amplitude of motor units = ?

Neuropathic process. Prolonged amplitude, because there are more muscle fibres than usual firing off (muscle units belonging to dead nerves get recruited by living ones). Polyphasic, because recruited muscle fibres lie outside the main area of the motor unit.

4

EMG with brief, low amplitude units, and early interference pattern = ?

Myopathic process. Disease which randomly knocks off muscle fibres.

5

If you see fibrillations (clinically) & sharp waves on EMG, you should think..?

ALWAYS think neuropathy (at least for BPT exam!)

6

Ramsay Hunt syndrome caused by? Bell's?

HZV (aka VZV).

7

T/F? There's evidence that antivirals within 72 hrs of Ramsay Hunt Syndrome developing will improve progonosis

True

8

T/F? R) MCA infarct (posterior division) can cause neglect

True, often in multiple areas, eg auditory, sensory, visuospatial. eg) pt fails intersecting pentagons on MMSE, difficulty putting on jacket, crowds all the numbers on the R) side of the clock face

9

How do you diagnose a small fibre neuropathy?

Skin biopsy - see destruction of small epidermal nerves.

10

What cells are causing MS? what do they secrete?

Th1 cells, secrete IFN-gamma. (NB: IFN-alpha is treatment for MS)

11

The most common cause of epilepsy in those > 65 yrs is?

Previous strokes

12

In paraneoplastic disorders, would ataxia be seen unilateral or bilateral (symmetrically)?

Symmetrical

13

Where would you expect to see brain mets?

Lodged between grey-white interface, where the vessels are the narrowest. However, brain mets can be anywhere.

14

What nerve involvement in VZV would mimic a presentation of meningitis?

Greater occipital nerve - goes in a path that when irritated can cause neck stiffness

15

Pt p/w ataxia, confusion, ophthalmoplegia, lateral gaze difficulty. Diagnosis?

Alcohol related nerve injury - treat with thiamine. Pts often have residual deficit - amnestic MCI.

16

Wernicke's encephalopathy carries what mortality rate?

1-2%. This condition is potentially reversible with thiamine

17

A pt with NHL p/w multiple nerve root involves (including CN 6 palsy, weakness in L5 distribution, diplopia, bladder disturbance, leg weakness, reduced / a/reflexia). Dx?

Lymphoma recurrence - multiple meningeal disease

18

With regards to postherpetic neuralgia, if simple analgesics (paracetamol, NSAIDs) fail, what is the next line of management?

Gabapentin (pregabalin similar efficacy; if one doesn't work though, try the other, sometimes a person will get a response). NNT = 3.

19

Name two indications for pregabalin (or gabapentin)?

Postherpetic neuralgic treatment (NNT = 3), DM neuropathy

20

What is the biggest risk factor for chronicity of postherpetic neuralgia?

Increasing age

21

What's the most appropriate first-line AED for JME?

Valproate. Change to lamotrigine if pre-pregnancy.

22

Which investigation best provides diagnosis for narcolepsy?

Mean sleep latency test

23

The following are classic symptoms of what? Excessive daytime sleepiness, catalpesy, hyponogogic hallucinations

Narcolepsy

24

What is a 'positive' (or 'abnormal') result in the mean sleep latency test?

Time for someone to fall asleep is

25

What's the treatment of narcolepsy?

Retanil - dexamphetamine

26

T/F? With regards to MS, PML has no mass effect and does not enhance on MRI brain

True. It's black on T1, white on T2, involves subcortical U-fibres, and is multifocal.

27

What's the baseline risk of PML for those with MS on natalizumab?

1 in 1000

28

What is wrong in PML?

PML is oligodendrocyte infection from JCV

29

What sort of vision do you get with an optic chiasm defect? How about an optic tract lesion? Posterior circulation stroke?

Optic chiasm - get tunnel vision

30

What causes myasthenia gravis?

Acetylcholine antibodies

31

You see a decremental response on NCS in what condition?

Myasthenia gravis - every stimulus uses up some ACh until there's none left

32

EEG 3 Hz generalised spike wave = ?

Childhood absence seizures

33

EEG focal spike wave activity = ?

Local epileptogenic activity, eg tumour, abscess

34

EEG triphasic waves = ?

Metabolic encephalopathy (probably liver)

35

Periodic sharp waves = ?

CJD

36

A Parkinson's picture and impaired downward saccades =

PSP

37

List the DDx for Parkinson features & symmetrical presentation, vs Parkinson features & asymmetrical presentation

Asymmetric = PD, corticobasal degeneration

38

Gentamicin ototoxicity causes 'imbalance', not 'vertigo'

Fact.

39

If someone is unconscious with symmetrical signs, you should worry about metabolic disturbance

A vascular event tends to be asymmetrical

40

Mixed UMN & LMN defect = ?

MND

41

With regards to MS, beta-interferon reduces future attacks by what %?

30%

42

How does natalizumab work? How much % does it reduce MS attacks?

Alfa-integrin antibody - stops T cells getting into CNS. 80% reduction in MS attacks.

43

Pyramidal' = ?

UMN

44

When does chemotherapy-associated neuropathy present?

Around the time chemo is given, not usually delayed presentation

45

Biceps jerk innervated by?

C5 > C6, Musculocutaneous nerve

46

Brachioradialis jerk innervated by?

C6 > C7, Radial Nerve

47

Triceps jerk innervated by?

C7, Radial nerve

48

Finger jerk innervated by?

C7, 8, Median & ulnar nerves

49

Knee jerk innervated by?

L3, L4, femoral nerve

50

Ankle jerk innervated by?

S1, posterior tibial (branch of sciatic nerve)

51

Plantar reflex innervated by?

UMN

52

Deltoid innervated by?

C5, auxillary

53

Infaspinatus innervated by?

C5, suprascapular nerve

54

Post-viral inflammatory brachial plexopathy?

Motor weakness in (can be single) nerve roots, a/w pain, occurs post viral infection.

55

Commonest cause of wasted first interossei

Ulnar nerve

56

Weak flexors / forearm muscles

Inclusion body myositis

57

DDx L5 vs common peroneal nerve lesion

Plantar flexion - S1, some S2, posterior tibial.

58

Knee extension innervated by?

L3, L4, femoral nerve

59

Knee flexion innervated by?

L4, L5, S1, S2, branches of sciatic nerve, mostly tibial nerve, some peroneal involvement

60

Hip flexion innervated by?

S2, 3, nerve to iliopsoas

61

Hip extension innervated by?

Gluteal nerves, L5, S1, S2

62

Hip adduction innervated by?

L2, L3, obturator nerve

63

Hip abduction innervated by?

Mainly L5 involvement

64

Oscillopathy - trouble tracking motions. Due to a problem with what nerve?

Vestibular nerve. Can be how gentamicin toxicity presents