pemeriksaan elektrodiagnostik pada neuropati

pemeriksaan elektrodiagnostik pada neuropati

PEMERIKSAAN ELEKTRODIAGNOSTIK
PADA NEUROPATI
HERIANTO
DIVISI NEUROLOGI
EKA HOSPITAL BSD
Update on Diabetic Neuropathy - Nov. 4th 2013
PENDAHULUAN


Px elektrodiagnostik (Edx) → gangguan
neuromuskuler
Edx rutin → - NCS
- RNS
- Late responses
- Needle EMG
Edx ↔ NCS + Needle EMG

Tujuan px Edx:
 Lokalisasi dan tingkat keparahan kelainan saraf tepi
 Tipe saraf tepi yang terlibat
 Patofisiologi yang mendasari → degenerasi aksonal
/ demielinisasi
 Perjalanan waktu

Pada umumnya tidak dapat menentukan
etiologi secara pasti
Anatomi
• Susunan saraf tepi meliputi:
– Saraf kranial
• (kecuali n. optikus)
– Radiks spinalis
– dorsal root ganglia
– peripheral nerve trunks and their
terminal branches
– Sistim saraf otonom
Saraf Tepi
Characteristics of the disease
Nerve cell body: motor neuron disease (1)
Motor neuron axon/neuromuscular junction:
peripheral neuropathy (2&3)
Muscle degeneration: myopathy (4)
Pola distribusi neuropati
Tipe-tipe saraf tepi
Saraf motorik – dari medulla spinalis ke otot
 Saraf sensorik – dari reseptor sensorik menuju
ke medula spinalis

Small fiber (pain, temperature)
 Large fiber (vibration, position, balance)


Saraf otonom – mengatur tekanan darah,
keringat, fungsi kandung kemih, denyut jantung,
peristaltik usus
Mekanisme kerusakan saraf tepi
PENENTUAN DERAJAT KERUSAKAN
SARAF TEPI
Edx membantu menentukan patomekanisme
neuropati - demielinisasi, degenerasi aksonal atau
tipe campuran.
 Demielinisasi → remielinisasi

›beberapa minggu

Degenerasi aksonal (primer/sekunder)
→ prognosis lebih buruk

Fase akut → secara klinis tidak dapat dibedakan
antara degenerasi aksonal dengan demielinisasi
•
Neuromuscular Junction
– Myasthenia Gravis
– Lambert-Eaton
– Myasthenic
- Syphilis, SS
paraneoplastic
– Muscle
Myelin Sheath
Sensory Ganglionitis
– Polymyositis
- Guillain-Barré Syndrome
- CIDP
– Rhabdomyolysis
- MCBN
•
Motor neuron Disease
– ALS/WNV
– Polio
– West Nile Virus
Axonal Neuropathy
– Diabetes
– Alcohol
Symptoms







Weakness
Pain
Burning
Thick soles
Walking on stones
Tingling
Imbalance
Stimulation
Simplified Model
A nerve is a Chain of Polarized Membrane Segments (Myelin Action).
Stimulation in one point generates a depolarization.
- +
- +
- +
- +
- +
- +
Electrical Shock
Mechanical Compression
Magnetic Field
+
- +
-
+
- +
A nerve could be depolarized by:
-
-
+
Current Stimulation
+ +
- +
- +
- +
- +
- +
- +
- +
-
+
- +
- +
-
NERVE
Supramaximal Stimuli
Min. 3 Times Sensory Threshold
Depolarization
+ - +
- +
- +
- +
- +
- +
- +
-
+
- +
- -
ORTHODROMIC
+
+
NERVE
ANTIDROMIC
Once a nerve is depolarized at some point,
a wave of depolarization passes in
both directions from that point.
Propagation - Refractory Period
+ +
- +
- +
- +
- +
- -
+ -
+ +
-
+
- +
- +
-
NERVE
Propagation by Successive Depolarization
followed by Repolarization.
Time before Repolarization is called
the Refractory Period.
Motor Latency
Motor Response
+ -
+ +
- +
- +
- +
- +
- +
-
+
- +
- +
S
MOTOR LATENCY
in ms =
Propagation Time
from S to M
- +
-
NERVE
M
NERVE CONDUCTION STUDIES
(NCS)
Nerve conduction study (NCS) :
stimulation and recording of electrical activity
individual peripheral nerves with sufficient accuracy, reproducibility,
and standardization




to determine normal values, characterize abnormal findings, and correlate
neurophysiologic-pathologic features.
These clinical studies are used to:
Diagnose focal and generalized disorders of peripheral nerves
Aid in the differentiation of primary nerve and muscle disorders (although
NCS itself evaluates nerve and not muscle)
Classify peripheral nerve conduction abnormalities due to axonal
degeneration, demyelination, and conduction block
Prognosticate regarding clinical course and efficacy of treatment
Motor Conduction
Median Nerve
Latency
Rec.
3.5 ms
Wrist
Stim. 1
8.2 ms
Elbow
Stim. 2
Diff.: 4.7 ms
Distance mm:
Recording: Surface Electrodes
Stimulation: Handgrip or Bipolar
240
C.V.: 51 m/s
Sensory Conduction
Ulnaris Nerve
AVERAGING
Stimulation
Latency ms
2.6
Distance mm
155
Digit V
CV
m/s
60
Latency ms
3.1
Distance mm
175
Recording
Digit IV
CV
m/s
56
Nerve Conduction Studies
•
•
Prolonged latency and conduction velocity
suggest pathology of the myelin sheath, which
is most commonly affected in entrapment and
demyelinating neuropathy.
Reduced CMAP indicates a loss of axons,
suggesting a more severe and longstanding
compression or degeneration (axonal
neuropathy).
F-waves and H-reflex



Useful for identifying
proximal segmental
demyelination
Can only be done
when motor
amplitude is > 1 mV
Extremely heightdependent
ELECTROMYOGRAPHY (EMG)
• The clinical study of the electrical activity
muscle fibers individually and collectively.
of
• This electrical activity can be recorded via surface or
needle electrodes.
• The latter being used far more commonly in the clinical
setting, and is evaluated during needle insertion, during
periods of rest (spontaneous activity), and during
periods of voluntary muscle contraction
Needle Electromyography: Data





Insertional Activity
Spontaneous Activity
Motor Unit Configuration
Motor Unit Recruitment
Interference Pattern
EMG - Normal
•
Normal spontaneous
activity - silent
•
Normal Motor Unit -3
phases
•
Normal firing of
multiple units, filling
screen
EMG - Abnormal
•
Fibrillations - single
muscle fibers
contract
•
Polyphasic MUPs reorganization of
motor units due to
axon loss and
reinnervation
•
Rapid firing of single,
polyphasic MUPs indicates axon loss
TAKE HOME MASSAGE
HAL-HAL PENTING YANG PERLU
DIPERHATIKAN DALAM PEMERIKSAAN EDX
1.
2.
3.
NCS dan EMG merupakan kelanjutan dari
pemeriksaan klinis
Bila didapatkan hasil yang meragukan,
selalu pikirkan kemungkinan adanya faktor
teknis.
Apabila kondisi pemeriksaan Edx
meragukan, lakukan pemeriksaan ulang.
5.
6.
7.
Temuan Edx harus dilaporkan dalam
konteks gejala klinis yang menyertai dan
diagnosis kerja dari klinisi yang merujuk
pasien.
Bila pertimbangan korelasi klinis-Edx
meragukan, jangan membuat diagnosis yang
berlebihan
Selalu pikirkan tentang korelasi kliniselektrofisiologis → gejala klinis, NCS dan
EMG
LIMITATIONS
• The limitations of EMG/NCS should be taken into
account when interpreting the findings.
– There is no reliable means of studying proximal
sensory nerves.
– NCS results can be normal in patients with small-fiber
neuropathies
– Lower extremity sensory responses can be absent in
normal elderly patients.
• EMG/NCS are not substitutes for a good clinical
examination.
When to order NCSs and EMG





Mononeuropathy
Mononeuropathy
Multiplex
Radiculopathy
Plexopathy (Brachial
or Lumbosacral)
Anterior Horn Cell
Disorders




Diffuse neuropathies
Cranial neuropathies
Neuromuscular
Junction Disorders
Myopathy
When Not to order NCSs and EMG






Central Nervous System Disorders (Stroke, TIA,
Encephalopathy, spinal cord injury)
Multiple Sclerosis
Total body fatigue, fibromyalgia
Joint pain
Unexplained weakness (without a neurologic
consultation)
Failed back, S/P multiple neck and low back
surgeries
TERIMA KASIH ATAS
PERHATIANNYA !!!
ASPEK TEKNIS PEMERIKSAAN
ELEKTRODIAGNOSTIK
MOTOR CONDUCTION STUDY
Motor NCS Parameters

Distal Latency


Amplitude


determined by conduction velocity of the nerve,
neuromuscular junction & muscle
determined by number of muscle fibers
activated
Proximal conduction velocity

determined by conduction velocity of the fastest
fibers
SENSORY CONDUCTION
STUDY
Sensory NCS Parameters



Onset and peak latencies
Conduction velocity
 determined by velocity of a very few
fast fibers
Amplitude
 determined by the number of large
sensory fibers activated
LATE RESPONSE
F- RESPONSE
F-RESPONSE
H-REFLEX
H-REFLEX
REPETITIVE NERVE STIMULATION
(RNS)
REPETITIVE NERVE STIMULATION
(RNS)
NEUROPHYSIOLOGY TRAINING
PROGRAM



EEG and EMG Workshop, Tan Tock Seng Hospital,
Singapore, November 2009
Neurophysiology Training, Neurophysiology Clinic,
Gasthuisberg University Hospital, Leuven – Belgium,
2011
Mayo Clinic EMG, EEG and Neurophysiology in Clinical
Practice, Mayo School of Continuous Development
Program, Jacksonville, Florida, USA, February 24 –
March 2, 2013