NM

Question 1

Define recruitment. What conditions is it decreased in?

Answer 1

firing frequency of the first motor unit when a second motor unit is recruited.
-decreased in ALS, radic, PN.

Question 2

Define MUAP. What conditions is it increased and decreased in?

Answer 2

spikes of electrical activity reflecting number of motor unit (motor neurons and muscle fibers they transmit to) activated when the patient voluntarily contracts a muscle.

• Increased in ALS, chronic radic and chronic axon loss.
• Decreased in myopathies.

Question 3

What drug is bad for MG with intubation? How reverse? What should be used instead?

Answer 3

Curonium is bad.
Reverse with sugammadex.
Can use inhaled fluranes instead.

Question 4

What is seen on muscle histology with steroid use?

Answer 4

type II muscle fiber atrophy

Question 5

What type of myopathy do statins cause?

Answer 5

necrotic and inflammatory

Question 6

Definition of CIDP v AIDP timeline. What is the role of steroids in these conditions?

Answer 6

• CIDP continues to progress or has relapses for > 4 wks, AIDP reaches nadir at 3-4 wks.
• Steroids make AIDP worse, used to treat CIDP.

Question 7

Difference between myasthenic crisis and cholinergic crisis

Answer 7

• myasthenic: defined as MG c/b RF requiring intubation. Happens in 20% patients. Triggers are infection, aspiration, trauma, childbirth, decrease in MG meds, reduction of other IS meds, Botox injections, meds (esp fluoroquinolones, amino glycosides, beta blockers, CCBs)
• cholinergic: overmedication w cholesterase drugs (too much parasympathetic muscarinic-abd pain, diarrhea, vomit and nicotinic-bronchial and nasal secretions, etc)

Question 8

When do you intubate/BiPAP a MG patient?

Answer 8

VC<10 ml/kg or

NIF < 20 (how much patient can suck in)

Question 9

MG paraneoplastic (thymoma) in ___% cases. .

Answer 9

10-15% Surgical resection is treatment.

Question 10

Lower limit of normal nerve conduction in BUE, BLE.

Answer 10

UE 50 m/sec, LE 40m/sec

Question 11

Kennedy syndrome and inheritance pattern

Answer 11

Bulbar weakness, fasciculations, gynecomastia

-CAG trinucleotide repeat

Question 12

Multifocal motor n uropathy (With conduction block)

Answer 12

• subacute onset of asymmetric weakness and LMN signs of arm and hand weakness without assoc sensory loss, patchy nerve involvement, often decr or absent reflexes in affected limb(s)
• Rx with steroids or IVIG

Question 13

IVIG dose

Answer 13

2g/kg over 2-5d (ie 0.4 g/kg daily for 5d)

Question 14

CMT inheritance pattern

Answer 14

duplication, PMP22

Question 15

Nonaka myostits

Answer 15

• distal myopathy in young ppl

- often p/w only TA inv (foot drop)

Question 16

paraspinal muscles are innervated by ___

Answer 16

dorsal rami directly off the spinal nerve roots

Question 17

How long does reinnervation take to see on EMG?

Answer 17

3 mo

Question 18

What indicates active denervation on an EMG?

Answer 18

fibrillation potentials and positive sharp waves (can also be seen in some myopathies and severe NMJ disease.

Question 19

Changes in NCS if < 32 degrees C

Answer 19

increase latency, CV, amplitude, duration of responses

Question 20

F response

Answer 20

motor response after CMAP, no synapse, all nerves in pathway are motor

Question 21

H reflex

Answer 21

• S1 reflex, stimulates the tibial nerve
• afferent is sensory/efferent is motor
• abnormal in tibial/sciatic neuropathy, sacral plexopathy, S1 radiculopathy, sensory neuropathy

Question 22

rapid repetitive stimulation in LEMS causes what on EMG?

Answer 22

facilitation in CMAP

Question 23

“machine like” sound on EMG

Answer 23

• complex repetitive discharges (single muscle fiber depolarizing spreading to other denervated fibers)
• chronic neuropathic and myopathic d/o

Question 24

“corn popping” sound on EMG

Answer 24

• fasciculations
• spontaneous discharge of individual motor unit*
• seen in motor neuron disease, radiculopathy, polyneuropathy, entrapment neuropathy, benign fasciculation syndrome.

Question 25

“marching soldiers” sound on EMG

Answer 25

-myokymia (like grouped firing of same motor unit whereas tremor is different motor units.)

Question 26

What are EMG findings in a myopathy?

Answer 26

polyphasia, early MUAP recruitment, decreased amplitude of MUAP, short duration and low amplitude. If there is muscle fiber necrosis may see abnormal spontaneous activity.

Question 27

Evolution of axonal loss on EMG:
<3d (hyperacute)
1wk - 3/6wks (acute)
3/6 wks - 2/3mos (subacute)
>2/3mos - many mos/y (subacute - chronic)
many yrs (chronic)

Answer 27

hyperacute - normal NCS, EMG with decr MUAP recr

acute - NCS: decr sensory and motor amp, normal CV and distal latency. EMG: +/- spontaneous activity in proximal muscles, decr MUAP recr

subacute - same as acute

chronic - NCS: same as acute although may be normal. EMG: decr MUAP recr, abn MUAP morphology (d/t reinnervation), no abnormal spontaneous activity

Question 28

NCS in acquired v hereditary demyelination

Answer 28

Acquired: conduction block*
Hereditary: NO conduction block*

Rest is the same: prolonged/increased distal latencies, slow/decreased conduction velocity

Question 29

EMG and NCS in CNS d/o

Answer 29

EMG: decreased activation
NCS: normal

Question 30

When does wallerian degeneration start?

Answer 30

motor nerves: day 3-5

sensory nerves: day 6-10

Question 31

Carpal tunnel exam

Answer 31

weakness in thumb opposition and adduction, thenar eminence wasting, decreased sensation in digits 1-3 and lateral 4th.

Question 32

Anterior interosseous mononeuropathy exam

Answer 32

-trouble making ‘ok’ sign
-weakness of flexor pollicus longus, flexor digitorum profundus (2-3) and pronator quadratus
(weakness in flexing distal thumb, index and middle finger and pronation with arm flexed.)
-no sensory loss