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64 Cards in this Set
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Vasculitic neuropathy
Labs/studies |
1. NCS: Look nL but are asymmetric
2. CSF: nL 3. Sensory n. bx: vasculitis 4. Muscle bx: increases yield |
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Vasculitic neuropathy
Clinical Features |
1. ASYMMETIC weakness & sensory loss
2. Painful 3. Tx w/ immsupp |
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Vasculitic neuropathy
Etiologies |
1. Pimary PNS vasculitis 25-30%
2. Systemic Vascultitis (RA SLE PAN Wegener) 3. DM 4. Leprosy 5. Sarcoid 6. Amyloidosis 7. Amphetamine-induced |
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Vasculitic Neuropathy
Definition |
Primary attack on small to medium sized bl vessels-->ischemia and infarction of isolated periph n.
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Axonopathy
Clinical features |
1. Distal wknss & atrophy
2. Distal sensory loss 3. Tingling/burning (stocking/glove) 4. Loss of AJ 5. No facial wkness 6. Chronic course 7. (decr potential for Tx/Rx) |
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Axonopathy
Definition |
Degeneration of distal axons w/secondary degen of myelin sheaths. Length-dep process.
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Axonopathy
Common Causes (categories) |
1. Metabolic
2. Endocrine 3. Drug/toxic 4. Idiopathic |
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Myelinopathy
Labs/studies |
1. NCS: slow prolonged distal & F-wave latencies
2. CSF elev protein 3. Albumino-cytologic dissoc 4. Sensory n. bx = demyel-remyel and inflamm. |
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Myelinopathy
Clinical features |
1. Prox AND distal wknss
2. Facial wkness 3. Variable sensory loss 4. AREFLEXIA 5. Acute or chronic course 6. Often good recovery |
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Myelinopathy
Etiologies |
1. Idiopathic (GBS CIDP aMAG Ab)
2. Hepatitis 3. Sarcoid 4. Mononucleosis 5. Lymphoma 6. HIV 7. Lead intox 8. Diphtheria (w/ l/o pupil accom) |
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Myopathy
Name major inflammatory myopathies |
1. Polymyositis
2. Dermatomyositis 3. Inclusion body myositis 4. HIV myositis |
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Myopathy
Polymyositis Clinical Features |
1. Age <20
2. Subacute to chronic onset 3. LIMB GIRDLE wknss 4. Neck flexors/pharyngeal m affected 5. Myalgia |
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Myopathy
Polymyositis Associated dz |
1. Interstitial lung dz
2. Cardiomyopathy 3. ARRHYTHMIAS 4. Esophageal paresis Call Pulm, Cards, ENT |
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Myopathy
Polymyositis Labs/Studies |
1. CK 5-10x nL
2. Assoc w/aAbs: Jo-1 PM-1 Mi-2 3. NCS/EMG: +Sharp waves/fibs and low ampl short dur polyphasic MUP 4. Muscle bx: necrosis phagocytosis endomysial inflamm (mix of CD8/MO |
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Myopathy
Polymyositis Pathophyz |
Cell-mediated autoimmune
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Myopathy
Dermatomyositis Pathophyz |
Humorally mediated autoimm dz
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Myopathy
Dermatomyositis Clinical features |
1. Children and adults
2. Subacute to chronic onset 3. LIMB GIRDLE wknss 4. ERYTHEMATYOUS SCALING MALAR AND EXTENSOR RASH w/ MCP/ICP Gottron's papules. 5. Periorbital edema 6. Joint contractures |
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Myopathy
Dermatomyositis Labs/studies |
1. CK elevated but no corr w/ dz
2. NCS/EMG: Pos Sharp wvs/fibs w/ small ampl and brief dur polyphasic MUP 3. Muscle bx: PERIFASCICULAR ATROPHY w/ perimysial/perivascular inflamm w/CD4 and B. Also MAC imm dep'n. |
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Myopathy
Dermatomyositis ASSOCIATED dz. |
1. MALIGNANCY
2. ARRHYTHMIAS 3. Angina 4. Uveitis 5. Retinopathy 6. Interstitial lung dz Call Cards Pulm Ophtho |
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Myopathy
Myositis Inclusion Body Myositis Epid & Clinical features |
1. MC inflamm myop >50 yo
2. M>F 3. ONSET LATE ADULT 4. CHRONIC 5. DISTAL ARM/PROX LEG: WRIST & FINGER FLEXORS AND QUADS 6. Dysphagia |
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Myopathy
Myositis Inclusion Body Myositis ASSOCIATED dz |
None, & no assoc w/ malig!
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Myopathy
Myositis Inclusion Body Myositis Labs/Studies |
1. CK<10x nL
2. NCS/EMG: MUP are COMBINED NEUROPATHIC and MYOPATHIC/ SNAPs often abn. 3. Muscle bx: rimmed vacuoles w/eosinophilic inclusions (trichrome)/amyloid dep'n/ENDOMYSIAL INFLAMM. |
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Myopathy
Myositis Inclusion Body Myositis Treatment |
?? Prednisone or IVIG
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Myopathy
Myositis Polymyositis/dermatomyositis Treatment |
1. Prednisone
2. MTX 3. Cyclophsphamide 4. Cyclosporine 5. IVIG |
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Myopathy
Myositis HIV Myositis Time of onset |
Early in the course of dz
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Myopathy
Myositis HIV Myositis Clinical features |
1. Painless
2. Limb-girdle wknss (no pharyngeal m. or resp m. involvement) |
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Myopathy
Myositis HIV Myositis Labs/studies |
1. NCS/EMG: similat to PM/DM
2. Muscle bx: interstitial perimysial inflamm and necrosis w/ nemaline rods in 50%. |
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Myopathy
Myositis HIV Myositis Treatment |
1. Prednisone
2. PEX 3. IVIG |
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F response
Define |
Small CMAP (1-5%). Pure motor, non-synaptic, antidromic to spine AHC-->firing for small # of AHC-->orthodromic to muscle. Gain must be 200 mcV. Turn cathode around. nL times: 25-32 msec UE and 45-56 msec LE. Often absent in peroneal n. Reinforce w/Jendrassik. F's abent in sleeping/sedated Pts.
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F response
Uses |
Early GBS
C8-T1 and L5-S1 radic (b/c these have recordable muscles) Polyneurop Internal control |
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F estimate
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Fest=(2X/NCV * 10)+1msec+Z
(the 10 is for conversion to msecs) X=Stim to AHC (msr by distance/NCV) Y= AHC turnaround (~1msec) Z=Distal latency (uses nerve length, NCV, latency; helps determine whether delay in F resp. is truly prox n. segment problem) |
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NMJ EMG
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-CMAP nL post synaptic (ie. MG)
-CMAP low ampl at rest in pre-synaptic (ie. LEMS, botul) -NORMAL NCV and latency -Use repetitive stim or exer testing to show NMJ dz. |
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Myopathy EMG
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-If Myop affects PROX muscle, nL CMAP ampl & distal latencies
-If distal muscle, decr CMAP ampl. -nL NCS and latency unless superimposed neuropathy |
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Demyelinating polyneuropathy
DDX |
HEREDITARY:
HMSN I (CMT) HMSN III (Dejerine-Sottas) HMSN IV (Refsum) HNPP Adrenoleukodystrophy Metachrom. Leuk. Krabbes Cockayne's Neimann-Pick Cerebrotendinous xanthomatosis ACQUIRED -CIDP (idio, HIV, MGUS IgM, aMAG, osteosclerotic myeloma, Waldenstrom) -MMN w/condxn block +/-GM1 Ab -Diptheria -Toxic (Amiodarone, Perhexiline, arsenic, glue-sniffing, buckthorn shrub) |
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Conduction block
Describe |
1. Any drop in either CMAP ampl or area >20% (if suspect incr temporal dispersion w/phase cancellation, use >50% drop between prox & distal sites)
2. Any incr in CMAP dur of >15% (abn temp disp). |
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Demyelination EMG
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1. Any motor, sensory, or mixed NCV <35 msec (UE) or 30 msec (LE)
2. Amplitude nL |
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Axon loss EMG
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1. Decreased amplitude
2. nL or slightly decr NCV 3. nL or slightly decr latency |
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SNAP low amplitude
(dx?) |
Definite disorder of peripheral nerve.
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SNAP conduction velocity
Compare to CMAP CV |
Direct msrmt (no NMJ or muscle to interfere)
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SNAP
Normal amplitude and stim qty. |
10-20 mcV (vy diff fr CMAP)
and usu stim = 5-30 mA |
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CMAP
Define latency |
A time including nerve travel, NMJ, and depolarization time of muscle
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CMAP duration
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Time from initial deflection to 1st baseline crossing. Measures synchrony and tends to increase in conditions slowing some fibers but not others (eg demyel. dz)
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CMAP ampl
Definition and stim qty |
# of muscle fibers that ultimately fire.
Gain = 2-5 mV Stim = 10-50 mA, incr by 10s to 50 |
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Motor Conduction velocity
Definition and mechanism |
CV not same as latency! (requires 2 stim sites: measure at muscle: subtracting time 1 from tine 2 will erase distal nerve, NMJ, and muscle time, leaving only NCV. Both CV & latency measure only FASTEST FIBERS.
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CMAP ampl decrease
Causes |
1. Axonal neuropathy
2. Conduction block betw stimulator and recorded muscle 3. some NMJ dz and myop. |
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Myopathy categories (6)
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1. Muscular Dystrophies
2. Inflammatory 3. Toxic 4. Congenital 5. Metabolic 6. Endocrine |
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NMJ dz (5)
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1. MG
2. LEMS 3. Botulism 4. Toxic 5. Congenital |
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Neuropathy broad causes (3)
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1. Entrapment
2. Polyneuropathy (demyel, axonal) 3. Mononeuritis multiplex |
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Plexopathy broad causes (6)
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1. Radiation
2. Neoplastic 3. Entrapment 4. DM 5. Hemorrhagic 6. Inflamm. |
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Radiculopathy broad causes (6)
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1. Disk
2. Spondylosis 3. Neoplastic 4. Infarction 5. Infectious 6. Inflammatory |
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Sensory neurop. categories (4)
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1. Paraneoplastic
2. Autoimm 3. Toxic 4. Infectious |
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Motor Neurop categories (4)
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1. ALS
2. SMA 3. Polio 4. Monomelic amyotrophy |
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Overall PNS organization
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Muscle--myopathy
NMJ Nerve--neuropathy Plexus--plexopathy Root--radiculopathy Motor or sensory neuron--neuronopathy |
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EMG: List the spontaneous discharges of NMJ/muscle fibers (5)w/discharge, source, rate, stability and pattern.
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1. Endplate noise MEPP 20-40Hz irreg pattern
2. Endplate spike terminal axon twig 5-50Hz sputtering 3. Fibrillation m.fiber 0.5-10Hz occ hi (30Hz) +stable +regular 4. Positive wave (same as fibs) 5. Myotonia m. fiber 20-150Hz wax/wane amplitude & regularity |
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EMG: List the spontaneous discharges of Motor units (5: one is odd)
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1. cplx repet discharges Multiple time-linked m. fibers (appear as discrete firings unlike motor unit) 5-100Hz usu stable&perfectly regular
2. Fascics Motor units 0.1-10Hz not stable&irreg. 3. Myokymia Motor unit 1-5Hz (if inter-burst) 5-60Hz (if intra burst) not stable & burstng. 4. Cramp Motor unit 20-150Hz Not stable Interference pattern of several MU 5. Neuromyotonia Motor Unit 150-250Hz Not stable Decrementing amplitude & waning |
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EMG: muscle fiber action postential (MFAP) is seen under what consitions?
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Spontaneous depolarization from 1. denervation
2. depolarization of an individual axon twig->NMJ->fiber |
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Blink reflex: describe anatomy and what makes up R1 and R2.
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Afferent: V1
Efferent: VII R1 circuit: V1 to Vmain nucleus to VII nucleus to VII (ipsi) R2 circuit: V1 to Vspinal nucleus to ipsi and contra VII nucleus and VII nerves. |
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EMG: name two common anomalous innervations or the limbs
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1. Martin-Gruber Anastomosis. (15-30%: fibers from Median n. travel with Ulnar n.)
2. Accesory peroneal nerve. (connection between superficial peroneal n. and ext dig brev.) |
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EMG: list common repetitive stim patterns: normal 3Hz, postsynaptic dz 3 Hz, and presynaptic dz 3 and 50 Hz.
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1. EPP ampl 40-32-26-20-26 (last rise b/c of secondary stores; no discharge below threshold (safety margin)
2. 1st EPP above threshold: all others decrementing below. 3. Smaller disharges than presynaptic: all below threshold. 4. Initial discharges very small but building above threshold b/c of retained calcium at high firing rate. |
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Repetitive stim technical factors
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1. T>33
2. Arm or m. of interest immobilized 3. Supramax stim 4. AChE inhibitors withheld 4 h prior to study. |
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Martin-Gruber and Carpal Tunnel Syndrome: what doae a median n. trace look like?
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1. Fast CV (b/c some of the fibers being tested to not go through the canal)
2. Prox>distal CMAP amplitude |
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Effect of temperature on NCS & EMG?
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1. Decr CV
2. Incr distal latency 3. Incr ampl and duration (CMAP & SNAP) 4. MUAPs may be slightly large & polyphasic as well. |
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Effect of age on NCV? CMAP & SNAP?
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1. NCV: birth = 50% of adult CV (incomplete myelination)
2. 20-40 = nL 3. >40: decr by 0.5-4.0 msec/decade. 4. CMAP/SNAP: decr w/ age (50% of nL by age 70) 5. MUAP: incr duration w/ age. |
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Effect of height on NCV?
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decr NCV by 2-4 m/s below lower limit of nL for extreme height (6'10", for ex.)
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