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29 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Components of ncs |
CMAP: VLAD (velocity, latency, amplitude, duration) SNAP: VLAD (use peak latency) |
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How to distinguish axonal vs demyelination |
Axonal: amplitude affected > velocity Demyelinating: velocity > amplitude |
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5 features of demyelination on ncs |
Conduction block: drop in CMAP amplitude of 50% (proximal normal, but distal low) Temporal dispersion: > proximal CMAP duration is 30% greater than distal CMAP (30% more spread out) slowed conduction Velocity: decreased by 30% (70% of normal) prolonged Distal latency: > = 50% of ULN (150% of normal cutoff) absent/delayed F waves: |
Amplitude, 3 velocity (temporal dispersion, CV, DL), F waves, HINT: CTV DF |
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Define f response, h response, a reflex |
F response: late motor response due to antidromic travel to anterior horn cell which bounces back along nerve, variable since different anterior horn cell stimulated each time. H response: electrical correlate of tendon reflex (sensory to motor) A reflex: small motor response after CMAP due to reinnervation (travels along collateral axon |
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Martin Geiger anastamosis |
crossover of motor fibers from median to ulnar nerve in forearm. In 15-30% ppl Median nerve will innervate ulnar muscles (ADM, FDI) and will look like ulnar conduction block |
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EMG components |
Spontaneous activity: muscle fiber: fibrillations, PSW, CRD, myotonic discharge (FPCM) motor unit/axon: fasciculation, doublet/triplet, myokimia, cramp, neuromyotonia (FDMDN) Voluntary activity: MUAP morphology: amplitude, duration, polyphasia, recruitment |
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EMG: neurogenic vs myopathic |
Neurogenic: decreased recruitment, MUAPs are large amplitude, long duration, polyphasic Myopathic: early recruitment, MUAPs are small amplitude, short duration, polyphasic |
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Timing of ncs/EMG changes in acute Adonai lesion |
Acute <1wk, early recruitment, otherwise normal 10-14d-wallerian degeneration = smaller CMAPs 1 month: abn spontaneous activity: fibs/PSW 2 months: large MUAPs Months-years: large MUAPs/decreased recruitment, CMAP may improve and spontaneous activity may resolve |
Hint: recruitment, CMAP, spontaneous activity, MUAP (1 wk/2wk/1mo/2mo) |
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Ddx of Anterior horn cell disease |
ALS, SMA1-3, Kennedy’s disease (x linked spinobulbar atrophy) Infectious: polio, post polio, WNV, HIV, HTLV-1 Toxic: lead, arsenic, thallium Other: delayed radiation induced MND, paraprotein related motor neuropathies, monomelic amyotrophy |
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ALS diagnostic criteria |
El Escorial criteria: combo of UMN and LMN in 4 areas (bulbar, cervical, thoracic, lumbar) a) evidence on LMN degeneration (clinical or electrophysiological) b) evidence if UMN degen c) progressive spread e) electrophysiology does not indicate another process d) imaging does not indicate another process definite (3 regions), probable (2 regions), suspected (1 region) |
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ALS vs MMN |
distribution of weakness, MMN is nerve, ALS is myotomal UMN findings only in ALS Bulbar weakness: in ALS not MMN NCS: demyelination in MMN, ALS often normal or reduced CMAPs EMG: ALS has more evidence of active denervation (fibs/PSW), involves paraspinals labs: antiGM1 in MMN |
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Genetics of ALS |
Genetics of ALS 5-10% are genetic (AD): C9ORF72 (30%), SOD1 (20%), TDP 43 (10%), FUS (5%) |
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ALS treatment |
riluzole - Edaravone: free radical scavenger. Overall analysis no benefit but subgroup analysis showed reduction of functional decline by 1/3 in those at earlier stage/milder disease (FVC> 80%, scoring 2+ points on all items on ALSFRS and disease duration <2yrs and moderate rate of progression) |
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Kennedy’s disease: features and genetics |
progressive limb and bulbar weakness, perio-oral fasic, gynecomastia, testicular atrophy/impotence/infertility, mild sensory neuropathy X linked androgen receptor gene, CAG expansion |
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SMA: genetics and subtypes |
SMA: explain the genetics and subtypes AR, deletion of the SMN1 gene (survival motor neuron) on chromosome 5 variable # of SMN2 genes determines SMA 1-3 SMA 1 (1 or 2 copies SMN2) never sit, death by age 2 SMA2 (3 copies SMN2) never walk, onset 6-18mo SMA3 (4 copies SMN2) never run, onset 5-15yo |
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List parts of brachial plexus |
Roots (C5-T1) => trunk (UML) => division = cords (lateral/post/medial |
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Features of the 3 trunks and 3 cords of brachial plexus |
Trunks: Upper: C5/6, Middle: C7, Lower: C8/T1 Cords: Lateral cord contributes to MSC and median Posterior: subscapular (teres major), thoracodorsal (lats), axillary and radial Medial: Medial cut of arm/forearm, median, ulnar |
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Distinguish: upper trunk (C5/6) vs lateral cord |
lateral cord spares axillary suprascapular (supra/infraspinatus) C6 radial (brachiorad) |
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Brachial plexopathy ddx |
trauma, neoplasm, radiation, diabetes, parsonage Turner syndrome |
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Radiation vs neoplastic plexopathy |
clinical: neoplastic more painful timing: neoplasm acute and faster, radiation delayed and slower location: radiation involve supper plexus, malignancy involves lower plexus EMG: myokymia in radiation, both have neurogenic changes imaging will show infiltrating lesion/ass in malignancy, rads may be normal or some T2hyper |
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Innervation and cause of damage in following nerves: long thoracic, suprascapular, axillary and musculocutaneous nerves |
Long thoracic (C5-7) = serratus anterior, due to brachial neuritis, surgery, trauma Suprascapular: weak in supra and infraspinatus, due to repetitive stretch injury Axillary: deltoid, trauma Musculocutaneous: biceps, due to trauma |
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Median nerve: list branches and innervation |
Motor: PT, FCR, FDS, FDP, FPL, PQ, LOAF AIN: FDP1/2, FPL, PQ (test pronation with arm flexed) Sensory: palmar branch Median neuropathy In antecubital fossa: rare, weak in all muscles AIN: pure motor, weakness of FPL, FDP 2,3, PQ At wrist: CTS |
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Ulnar nerve: list branches and innervation |
Motor: FCU, FDP 3,4, LOAF of digit minimi, FDI, Adductor pol Sensory: DUC, palmar cutaneous branch, terminal branches Ulnar neuropathy At elbow: very common, affects all ulnar, benediction sign-clawing of D4/5, froment’s sign-weak FDI/Ad Pol At wrist: spares sensory of dorsal ulnar hand and medial palm. Spares FCU and FDP |
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Radial nerve |
Triceps, BR, ECR, Supinator, ECU, EDS, EDM Abd pol, Ext pol, EIP PIN: pure motor, involves everything distal to Supinator |
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Radial neuropathies |
Axilla – crutches/compression- entire radial nerve affected spiral groove/Saturday night palsy: spares triceps PIN neuropathy: pure motor, spares triceps and ulnar wrist extension (wrist radially deviated) finger extensors, thumb extension impaired Superficial radial sensory neuropathy/handcuff beuropathy: dorsum of the hand numb |
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CTS risk factors, clinical features, treatment and prognosis |
RF: pregnancy, DM, hypothyroid, acromegaly, HNPP, RA, masses, amyloid, renal failure Clinical features, nocturnal paresthesias, numbness, weakness, phalen, tinnel Treat: wrist splint, surgery if progressive/severe symptoms |
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Radic vs nerves: muscle to differentiate bw: C6/median, c7/radial, C8/ulna |
C6 vs median: non median C6 brachioradialis (radial) C7 vs radial: brachioradialis (radial not C7) C8 vs ulnar: non ulnar C8: FPL (median), EIP (radial) |
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Lumbosacral plexus: compare upper vs lower plexus weakness |
Upper plexus: L2-L4, weak hip flexion, adduction, knee extension lower plexus: L5-S3: weak hip abduction, extension, knee flexion, all ankle muscles |
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femoral nerve innervation |
HF (iliacus), KE (quads:rectus femoris, vastus lateralis, intermedium and medialis) Sensory: medial cut nerve of thigh |
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