Polyneuropathy Flashcards
what are the three types of polyneuropathy?
- Axonopathy
- Myelinopathy
- Neuronopathy
What is the temporal profile that you can learn from EMG (3)
Acute 21 days 5 months
Subacute 6-11 months
Chronic 12-18 months
What are the 4 predominant pathologies in peripheral neuropathy?
A. Axonal
B. Uniform demyelinating (usually hereditary)
C. Segmental demyelinating (usually acquired)
D. Axonal & Demyelinating (classic example is diabetes)
What three things about polyneuropathy must you know to correctly diagnose?
- generalized process
- symmetric vs asymmetric
- multifocal (spotty distribution)
During polyneuropathy protocol:
1. Test ____ site
2. Start with _____ study
3. If abnormal –> ____
4. If no response –> ____
- most involved site when mild-to-moderate. Least involved if severe.
- a. Peroneal motor (EDB) - stim at ankle and knee. record F response latency. If no response or abnormal response move to 3 or 4.
b. Sural sensory
c. Median sensory or ulnar (since high incidence of median pathology) - tibial motor (abd hall) stim at ankle and knee; record F response latency
- peroneal motor (anterior tibial) stim at fibula and knee.
ulnar motor (hypothenar) stim at elbow and wrist
measure F response latency
Median motor (thenar) stim at elbow and wrist
measure F response latency
If prominent CN involvement, stim at facial motor and blink reflex.
Needle exam
- anterior tib
- medial gastroc
- first DI
- lumbar paraspinals
(if normal, intrinsic foot muscles should be tested.
Nickerson protocol for polyneuropathy:
Lower ext sensory:
Upper ext sensory:
Lower ext motor:
Upper ext motor:
plus?
EMG:
Usually do longest sensory
Sural bilat - if can’t get, do superficial peroneal (peroneal commonly used as can get prox and distal stim)
ulnar - bc median pathology is common
peroneal and tibial
ulnar - F wave
do long loop (H waves and F reflexes)
EMG: sample lower extremity first. If abnormal do contralateral muscle
radic screen: atleast 5.
Tib ant, med gastroc, FDI
Upper, FDI and biceps (something distal and something proximal)
In axonopathy, will have ____ phenomenon
_____ nerves and ____ fibers are affected first
___ is spared
___ is preserved if corrected
Overall, will see ____ and ___ on NCS
Prognosis:
dying back (not exclusive)
longest/largest
myelin sheath
endoneurium
decreased amplitude and area under the curve
slow re-growth and return of function over months to years.
incomplete recovery.
Myelinopathy spares ____ but affects ______.
subsequent ____ loss occurs
______focal
distal or proximal?
Prognosis:
Recovery:
schwan cell, myeline sheath.
axonal loss (slight amount of axonal injury)
multifocal/segmental demyelination - doesn’t strip entire nerve.
- affects node of ranvier (multisites)
- proximal before distal
- uniform or segmental
prog: weeks to months
Functional recovery better than axonopathy
incomplete recovery
In acquired, will have excessive temperal dispersion (spread out, extra bumps), not in hereditary.
Name the two most common uniform demyelinating mixed sensorimotor peripheral neruopathies
- HMSN I, II, IV
- Krabbe Leukodystrophy
Name the three most common segmental demyelinating motor>sensory peripheral neuropathies
Other 6?
- AIDP
- CIDP
- MGUS
- Arsenic
- Toxins
- Diptheria
- AIDS
- Leprosy
- Lyme disease
Name the 4 most common axon loss motor > sensory peripheral neuropathies
other 3?
- Porphyria
- Vincristing
- Axonal GBS
- HMSN II, V
- Dapsone
- AIDP
- Lead
Name the 3 most common axonal loss sensory neuronopathy
Other 3
- HSN I-V
- Friedreich’s ataxia
- cisplatinum
- Sjogren’s syndrome
- Pyridoxine
- Crohn’s disease
Name the three most common axon loss mixed sensorimotor peripheral neuropathies
other 9?
- Critical illness polyneuropathy
- ETOH
- Toxic
- Amyloidosis
- Vit B12
- Folate
- Gold
- Mercury
- Paraneoplastic syndrome
- Sarcoidosis
- Lyme disease
- HIV related
Name the 2 most common mixed axonal and demyelinating sensorimotor peripheral neuropathies
DM
uremia
_____ is a condition that affects the cell body (DRG or anterior horn cell)
Neuronopathy
sensory neuronopathies fit in this category as well.
If a myelin problem, will get what 3 things on NCS?
onset or peak latency delay
CV decreased
temporal dispersion
Is this physiologic or pathologic temporal dispersion?
stimulate proximally you get amplitude x, stimulate distally and get slightly lower amplitude; this will happen with all nerves (this happens because longer length, some axons get there at the same time, there is phase cancellation, and the amplitude is decreased) The area under the curve will remain constant
Physiologic
Is this physiologic or pathologic temporal dispersion?
stimulate proximally you get amplitude x, stimulate distally and you get an amplitude more than 20% less than x (less than 15% change in negative duration of wave). Overall curve is shortened (amplitude) and more spread out (duration). The area under the curve stays similar.
pathologic
____ will be decrease in amplitude without increase in duration of the wave. Can be confused with_____
partial conduction block
pathologic temporal dispersion.
What will be seen on axonal process for EMG
increased insertional activity
abnormal spontaneous activity - fibs/PSW
- reinnervation potentials (polyphasics, serrations, increased amplitudes, CRD if chronic)
- wont see abnormal spontaneous activity in demyelinating
wont see _____ on EMG in demyelinating process
abnormal spontaneous activity
Distal latency:
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
increased
increased
normal or slightly increased
normal or slightly increased
Nerve conduction velocity
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
decreased
decreased
normal or slightly decreased
normal or slightly decreased
F-latency
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
increased or absent
increased or absent
normal or absent
normal or absent
H-reflex
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
increased latency or absent
increased latency or absent
absent
absent
SNAP amplitude
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
Decreased or absent
decreased or absent
decreased or absent
decreased or absent
CMAP amplitude
Early demyelinating:
Chronic demyelinating:
Acute axonal:
Chronic axonal:
normal or decreased
normal or decreased
decreased
decreased