Motor Neuron disorders Flashcards
bulbar means involvement of ______
and involves CN: (4)
brain stem (medulla oblongata)
9, 10, 11, 12
Motor Neuron Diseases:
1. LMN lesion
2. U and LMN lesion
3. UMN lesion
- spinal muscle atrophy (SMA)
- poliomyelitis
- postpolio syndrome
- Amyotrophic lateral sclerosis
- Primary lateral sclerosis
____ is spinal anterior horn cell loss, LMN with little to no bulbar involvement
spinal muscle atrophy (Primary muscular atrophy)
____ is degeneration of bulbar nuclei, not c/w LMN or UMN signs
adult onset progressive bulbar palsy
____ is a UMN spastic paraparesis without cerebellar dysfunction
primary lateral sclerosis
Primary musculature atrophy:
1. Weakness and atrophy without _____
2. ____ motor neuron lesions
3. male vs female
4. symmetric?
5. presents with:
- hyperreflexia
- lower
- Male:femal 3.5:1
- symmetric
- wasting of intrinsic hand muscles (can’t open jars)
_____ occurs when weakness and motor wasting predominate in the muscles innervated by the motor nuclei of the lower brainstem. Will see weakness of muscles of the jaw, face, tongue, pharynx, and larynx.
adult progressive bulbar palsy
in Adult progressive bulbar palsy
no ____ signs
no _____ cell problems
male ____ female
Onset age _____
UMN
AH cell problems (no somatic problems in the limbs)
=
60-70s
in the differential of those people with ALS who present in their 70s but these people have it localized to the brainstem nuclei, not in the limbs
PLS is degeneration of _____ tract.
no _____ signs
no _____ signs
Mean age onset:
corticospinal tract
bulbar
LMN
53.4 yoa
spastic paraparesis, no sensory abnormalities, no cerebellar dysfunction, normal intellect, no LMN signs.
Rare, non-familial disease of unknown etiology
Amyotropic Lateral Sclerosis
- incidence
- some areas of higher incidence (3)
- prevalence
Age onset
Age of death
Disease duration
male:female
I: 0.4-1.5/100,000
sweden, guam, kiwi peninsula of Japan
P: 4-6/100,000
Age 52-66
Death 62 years
Usual disease duration: 3 years
- early onset 45 mo
- late onset 25 mo
- 3:1
etiology of ALS:
___% are familial
Gene defect?
Abnormal _______
if familial, age of onset:
male:female
Duration of illness: ____
speculative; most are idiopathic
5% are AD familial
Long arm Ch 21
form of enzyme superoxide dismutase
45-48
1:1
2.5 years
Initial symptoms ALS
____ % with arm symptoms
____% with bulbar symptoms
____% with LE symptoms
40-60%
25-30%
20%
no sensory symptoms
ALS:
Painless ____
symmetric?
If presenting with bulbar symptoms, will have ____ and ____.
weakness
asymmetric progresses to symmetric
dysarthria and dysphagia
_____ is seen with weakness, atrophy, fasciculations in different part of body wehre they have weakness, increased reflexes, increased tone, clonus, plantar responses are upgoing. Increased jaw jerk reflex, increase SNOUT because of hyperreflexia of bulbar muscles
ALS
____ and ____ are typically spared in ALS
EOM and bowel/bladder function (sphincter muscles)
in ALS, ____ and ____ suggest worse prognosis
older onset and bulbar presenting symptoms
Early ALS will have
_____ sensory NCS
_____ motor NCS
___ shows up pathology first
normal
normal
onset latency
simple rule for diagnosing ALS on EMG/NCS
abnormal spontaneous activity in 3 limbs or 2 limbs with bulbar findings.
fasciculations (LMN findings) in the same distribution, result of loss of anterior horn cells.
as ALS progresses, what happens to motor NCS
- CMAP amplitude gets smaller (death of AH cells and motor units)
(gets less than 30% of the mean) - slowed CV (fastest fibers are dead)
(typically never less than 70% of the mean)
______ paraspinals are the best muscles to test
why?
less overlap and less DJD
EMG findings on ALS:
1. Insertional activity:
2. Spontaneous activity:
3. Voluntary MUAP:
- increased
- fibs/PSWs, fasciculations. If chronic, will see CRDs
- decreased recruitment, motor units firing faster but not bringing in any other motor units to get more strength
- depending on where you are in disease progression, can see polyphasics because reinnervation process is going on. If you catch it at the very end, you see giant amplitudes as the one or two surviving motor units get much larger.
What are the parameters for polyneuropathy on MND
(3)
- distal latency is > 125% of upper limit of nml (sensory NCS)
- If CV is 10% of normal - prob polyneuroapthy
F waves and long loops on ALS:
____ latency
F waves show increased _____
increased latency (not > 10%)
chronodispersion (there is a big change from the fastest to the latest (5-10msec) in those 10 in a row.
What is unique about H reflexes and ALS?
Typically only seen in gastrocsoleus and FCR but will show up in H reflex shows up in other muscle nerve groups. When you’re first born, all muscles have the H reflex, no ALS is like an immature muscle system.
In repetitive stimulation with ALS, will see: (2)
on single fiber EMG will see increased ____ and _____
- decrease of CMAP of 20-25% at 3 hz repetitive stimulation (slow rate)
“20-25% decriment between the 1st and 5th response
2.
_____ are spontaneous depolarizations from anywhere between the AH cell and the NMJ. They are irregular and have any wave form.
fasciculations
waveform is nothing specific but it is irregular. The only way to tell if benign or malignant is based on the company that they keep. if Fibs and PSWs then it is likely pathological.
fasciculations alone can be caused by (3)
if found in disease process, it is a _____ process.
If in 3 extremities, probably _____.
sleep deprivation, caffeine, stress
LMN
ALS
no two fasciculations look the same.
voluntary activity on EMG for ALS would be:
decreased recruitment.
Explain recruitment ration
fastest firing motor units divided by the number of different motor units on the screen.
Myopathic process will have a recruitment ratio of ____
<5
Normal is 5; near 10 is neuropathic
EMG needle findings on ALS
1. spontaneous
2. voluntary
can also get unstable ____
- FIb, PSW, CRD, Fasic
- polyphasic, increased amplitude, decreased recruitment, increased duration
can also get unstable MUAP due to blocking at the NMJ (amplitude decreases) “poor mans single fiber EMG)
What indicates a poor prognosis prognosis on EMG (4)
- if CMAP amplitude is <20% lower limit of normal
- if decrement on repetitive nerve stimulation
- if you see the MUAP changing size on regular EMG
- density of fib potentials does not help with prognosis
- jitter does not help with prognosis
What is the world federation of neurology classification for ALS?
YES: UMN and LMN at 3 levels (bulbar, cervical, thoracic, and lumbar)
PROBABLE: UMN and LMN at 2 levels
POSSIBLE: UMN and LMN at 1 level or UMN at 2 levels
SUSPECT: LMN at 2 levels or UMN at 1 level
Name the 3 groups of have standardized diagnosis of ALS
- World federation of neurology
- El escorial criteria - 1990 “too restrictive”
- Awaji Shima Criteria - 2008 - clinical diagnosis
fasciculation potentials equal acute denervation. Given = consideration to PSW/fibs
Name the top 4 ddx for ALS, which of these are top two?
5-11?
- Cervical spondylosis with myelopathy
- motor polyradiculopathy
- multifocal motor neuropathy w/ partial conduction block
- CIDP
1 & 3
- polyneuropathy
- SMA
- focal amyotropy
8 primary lateral sclerosis - MS
- myositis
- MG
What is seen?
sensory NCS is normal. Notor distally is normal. Proximally amplitude is decreased by 50% with slowing across that segment. IgM ab GM1 ganglioside to blame
multifocal motor neuropathy with partial CB
CB - stimulate below it and it has a certain amplitude, go above it and stimulate and it doesn’t disperse out. It shrinks. The area under the curve decreases. You can see this in ALS. Key is this according to reading, you can do it in very small increments. ie 3 cm proximal and see if CB in a short segment of the nerve. In ALS it will be in a longer segment
a motor polyradiculopathy would have multifocal _____ affecting ___ limbs which would have more ____ motor neuron issues
foramenal stenosis, 3 limbs, LMN
no sensory findings
CIDP is purely ____ motor neuron.
lower
will see temporal dispersion. slow form of GBS
____ is a X-linked bulbospinal neuronopathy that is slowly progressive and affects bulbar muscles, spinal muscles, neuropthy (AH cells). Associated with gynecomastia and testicular atrophy.
Kennedy’s syndrome
age of onset is much younger than als patients. Presentation is symmetric
____ is the most common MND in kids
SMA
what are the 4 types of SMA
1 Werdnig Hoffmans disease - rapidly progressive, onset < 6 months, fatal
- Intermediate - onset 6-18 months; slowly progressive, relatively benign
- Kugelberg Welander - onset > 18 mo, or adolescents, longer survival rate
- Adult onset - “progressive muscle atrophy of adult onset”. Mostly LMN.
clinically all forms hae proximal weakness.
Polio caused by ____ which is a virus in ____ species
enterovirus
picornovaridae
in Polio
Sensory NCS:
Motor NCS:
EMG:
normal
normal at first: CV lower end of normal, amp/latency latechanges late
EMG - same as MNDs except focal
Polio is asymetrical and affects ___ more than ____
lumbar/sacral roots > than cervical or brainstem
____% of patients with polio develop additional dysfunction 30 years later
25-60% “post-polio syndrome”
What are the two different categories of post-polio syndrome?
- primary musculoskeletal - new onset of fatigue (90%), multi-joint pain in 85%. Myalgias (70-80%) Decreased mobility. Loss of function and a lot of stress (emotional component)
- Progressive muscular atrophy: slow progressive loss of strength, myalgia possible. Loss of strength in previously spared muscles (of the same limb that was affected)
for diagnosis of post-polio syndrome, must have (4)
- Previous hx of polio
- functional stability for 15 years
- residual muscle atrophy and areflexia (single limb combined with normal sensation)
- new onset of s/s that cant be explained by another disease
There is ____ evidence that someone with polio has more prone to ALS
no
How do you tell stable polio and post-polio syndrome apart on EMG
you cant
Can see most of the EMG findings in ALS in ____
post polio
