Motor Neuron Lesions

what age do most infants with type 1 wernig hoffman die

2

clinical signs of __________ will occur later in the disease

LMN

if ALS progresses superiorly from cervical level

LMN of phrenic nerve will be effected, comprising respiration

trasection will cause loss of

bowel and bladder control

what is another name for hemisection

brown sequard syndrome

lateral hemisection of the cord due to

bullet or knife injury

where does syringomyelia occur ?

central cavitation of the spinal cord, usually in the cervical region with a glial reaction, adjacent to the cavity (gliosiasastryocytes hypertrophy, multiply, and may become phagocytic)

what virus is MS associated with?

epstein bar viruses

lesions of upper motor neurons may have hyper stiffness- what is this

excessive resistance to both passive and active muscle stretch

why do lesions of upper motor neurons lead to spastic paresis?

inadequate recruitment of LMN

lesions of lower motor neurons: Werdnig Hoffman disease

infantile spinal muscular atrophies (SMAs)

where do cavitation and gloss spread in syringomyelia?

into the gray matter and white matters well as longitudinally leading to variable signs and symptoms depending on the regions involved

lesions of lower motor neurons: fibrillations

invisible brief electrical potentials detected by electromyography

lesions of the posterior column effect __________ and begin immediately ____________ the level of the lesion

ipsilateral immediately below

if the ventral horn is effected in hemisection

ipsilateral flaccid paralysis of innervated muscle

if dorsal column are effected in hemisection

ipsilateral loss of tactile discrimination, position sensation and vibration sensation

if lateral corticospinal tract are effected in hemisection

ipsilateral spastic paresis with pyramidal signs below the lesion

lesions of the posterior columns: tabes dorsalis is _______involvement of the ___________ root which results in _________ and __________

irriative dorsal pain and paresthesias

in syringomelia the central canal gets

larger

Lesions of posterior column: how are lesions in MS?

lesions are random and asymmetric

below the level of the lesion

lose corticospinal = ipsilateral (UMN) lose lateral spinothalamic = contralateral (pain and temp) lose dorsal columns = ipsilateral (fine touch, position and vibration sense)

lesions of lower motor neurons: poliomyelitis

loss of LMNs in the ventral horn caused by the polio virus

lesions of the posterior column result in

loss of joint position sensation, vibratory and pressure sensation, and 2 point discrimination

lesions of the posterior column: tabes dorsalis is characterized by

loss of tactile discrimination and positions and vibration sensation

lesions of lower motor neurons: flacidity

low muscle tone

ALS begins in _________ of the cord that supples the upper limb

lower cervical segment (40%)

at the level of lesion we will see

lower motor neuron sign

spinal shock will present

lower motor neuron signs

the first signs of transection look like

lower motor neuron- spinal shock

ALS begins in ________________ that supply the lower limb

lumbosacral segment (40%)

Is ALS more common in males of females

males 3:2

lesions of the posterior column: multiple sclerosis leads to what sensory issues

may have numbness, parasthesias, lehrmitte's sign

lesions of upper motor neurons are not effecting __________ directly but are a dysfunction of _______________ or ______________

motor neurons descending motor control motor neurons (ex-brain lesion)

Lesions of the posterior column: if multiple sclerosis effects the descending motor tracts we will see

muscle weakness

example of superficial reflexes: abdominal wall stroked

musculature contracts and umbilicus deviates to side of stimulus

what is syringomyelia?

neuronal degeneration that is not a primary pathalogical change

lesions of the posterior column: tabes dorsalis is seen in patients with

neurosyphilis

in transection will bowel and bladder control return

no

in ALS at the level of the lesion in muscles

of the upper limbs and bilateral spastic weakness (UMN sign) below the lesion in muscles of lower limb

If lesion of upper motor neuron is below decussation of pyramids

paresis is ipsilateral and below the level of the lesion

principal causative factor is vitamin b12 deficiency and is typically encountered in association with

pernicious anemia (treatment is injections)

lesions of the posterior column: what is involved in multiple sclerosis

plaques involve mostly the white matter of the cervical segment of the spinal cord

lesions in subacute combined degeneration result in loss of

senses of position, descriminative touch and vibration

patients with ALS at caudal brainstem levels may have difficulty

swallowing and difficulty speaking

Example of Posterior column lesion

tabes dorsalis

below level of lesion

upper motor neuron signs

later (after swelling, edema, hemmorrhage is gone) it looks like

upper motor neuron syndrome

thrombosis or occlusion of anterior spinal artery: what areas are supplied by this artery

ventral and lateral funiculi, most of gray matter

subacute combined degeneration is also called

vitamin B12 neuropathy

syringomyelia: spreading of the cavitation and glial reaction into the lateral funiculi may result in

voluntary paresis of upper motor neuron type, affecting especially the lower limbs

lesions of lower motor neurons results in absence of ____________ or ___________ contraction of ___________ muscle

voluntary, relex, denervated muscle (paralyzed)

why do parties with ALS at caudal brainstem have difficulty swallowing and speaking

weakness of pharyngeal or tongue muscles intreated by cranial nerves IX and XII

lesions of the posterior column: what are the signs of multiple sclerosis

weakness, incoordination, scanning speech (halting monosyllabic), involuntary oscillation of eyeballs, coarse tremor

is wernig- Hoffman disease hereditary?

yes

what is the classical clinical picture of syringomyelia?

yoke like anesthesia for pain and temperature over the shoulder and upper limbs accompanied by lower motor neuron (ventral gray) weakness and consequent wasting of the muscles of the upper limbs

if lesion occurs between C1 and C3

Respiration stops

Lesions of posterior column: MS appears to be an ______________ disorder

autoimmune

what kind of hereditary is wernig hoffman disease

autosomal recessive

lesions of lower motor neurons result in _________ at what location?

flaccid paralysis ipsilateral to and at the level of lesion

how to test for hoffmans sign

flicking nail of patients middle finger

example of lesion of the posterior column

multiple scerosis

what is typical cause of death in ALS

respiratory complications

how is lesions of posterior column typically evaluated

testing vibratory sense using a 128--Hz tuning fork

lesions of upper motor neurons have loss of fractionation of movement: what is this?

ability to activate muscles separately from others

lesions of the posterior column: patients with a romberg sign show

abnormal unsteadiness is noted wie the patient stands with feet together and the eyes closed, thereby evaluating proprioception in the lower limbs

onset of symptoms is _______ and is often accompanied by _______________

abrupt severe pain- sudden and severe caudally radiating back pain

what does ALS effect?

affecting corticospinal tracts along with cranial nerves and ventral horn motor cells

Lesions of lower motor neuron effects _______ or is ___________ en route to _______________

alpha motor neuron, peripheral motor axon, skeletal muscle

lesions of the posterior column: what is paresthesias

an unusual sensation such as burning, tingling, or numbness

how to test for altered cutaneous reflex

babinski sign

why will bladder control not return

because parasympathetic motor fibers travel on corticospinal to S2-S4 (which was cut with voluntary motor fibers in corticospinal tract)

accompanying spastic paraplegia results from

bilateral corticospinal tract invilvement (UMN, both sides, everything below the level of the lesion)

in ALS cervical levels experience

bilateral flaccid weakness (LMN signs)

what can subacute combined degeneration lead to

bilateral spastic paralysis with upper motor neuron signs (dorsolateral funiculus contains lateral corticospinal tracts)

ALS is (bilateral/unilateral) and (reginerative/ degenerative)

bilateral, degenerative

where are demylination and loss of nerve fibers in subacute combined degeneration

bilaterally in the dorsal and dorsolateral funiculi

if the lateral spinothalamic tract are effected in hemisection

contralateral loss of pain and temperature sensation beginning one segment below the lesion

ALS effects LMN in ______________

cranial nerves

if there is an upper motor neuron lesion may have altered _______ reflex

cutaneous

in syringomyelia what is interrupted early in the disease and causes a burn that is not painful

decussating fibers for pain and temperature in the ventral white commissar (lateral spinothal)

lesions of lower motor neurons: Werdnig Hoffman disease leads to (3)

destruction of LMNs in infants or young children infants may have difficulty sucking, swallowing, or breathing weakness in the limbs (floppy baby)

bilateral atrophy, fasiculation, flaccid paraysis, hypo/areflexia at the level of the lesion because

destruction of the anterior horn cells

what is the primary area affected in subacute combined degeneration

dorsal and dorsal lateral column

lesions of upper motor neurons lead to __________ or _______ muscle stretch reflex due to ________________

elevated or hyperactive inhibition of gamma motor neurons

what (4) things may lesions of upper motor neurons lead to?

elevated or hyperactive stretch muscle reflex may have clonus loss of fractionation of movement hyperstiffness

lesions of the posterior column: multiple sclerosis is a loss of ________________ which is replaced by ________________

fatty myelin sheath scar tissue

how is gait in subacute combined degeneration and why?

gait is ataxic (without coordination) because the patient is unaware of the position of the leg (because spinocerebellar tract travels in posterior column)

ALS releases _________ (neurotransmiter) and causes ____________

glutamate excitotoxicity

at the level of the lesion in hemisection

have segmental signs on same side

if there is an upper motor lesion my have ___________ sign

hoffmans

usually lose _________ and _____________ sense beginning _________________ _____________ the lesion because of

pain and temperature 1-2 segments below bilateral lateral spinothalmic tract damage

If lesion of upper motor neuron is above the decussation of pyramids

paresis is contralateral and below level of lesion)

lesions of the posterior column: if multiple sclerosis affects the posterior column we will see

posterior column signs

positive hoffmans test would show

prompt adduction of thumb and flexion of the index finger

lesions of UMN and LMN: ALS is what kind of disease

pure motor system disease

lesions of the posterior column: multiple sclerosis lesions are

random and asymmetric

lesions of lower motor neurons: fasicilations

randoms twitches of denervated motor units beneath the skin

lesions of upper motor neurons may have clonus: what is this?

rapid successive reflex contractions and relaxations (rhythmic)of agonists observed mainly at the knee and ankle joints during reflex testing

immediately following a trascection of the spinal cord

sensation and all voluntary movement are lost below the level of the lesion

Lesions of lower motor neurons: post polio syndrome

some of motor neurons that were not destroyed create extra branches- as we age they are unable to support extra branches so neuron dies

what does transection look like upper motor neuron syndrome

spastic paralysis below the level of the region, hyperflexia

what does a lesion of upper motor neurons lead to

spastic paresis

types of upper motor neuron lesions

spinal cord injury, stroke, congenital lesions, may also include head trauma, tumors, spastic CP, and MS

lesions of lower motor neuron leads to absence of suppressed muscle ________________

stretch reflex (hyporeflexia, areflexia, hypotonicity

lesions of upper motor neurons: cremaster relex

stroke inner thigh of male, testicle elevated on side of stimulus

how to conduct babinski test

stroke sole of foot- toes should curl if normal

superficial reflexes

stroking certain areas of the skin may be absent in UML

in syringomyelia the cavitation and glial reaction spread into

the lateral funiculi (lateral corticospinal)

only effecting the neurons where

the lesions are happening

where is thrombosis most common

thoracic region

what does a positive babinski test look like

toes should flare (bad) less than 7 months old (normal)

typical lifespan of ALS

typically dies within 3 years of diagnosis

lesions of the posterior column: what is the cause of multiple sclerosis

unknown

transection: quadriplegia/tetraplegia

upper cervical cord; paraplegic b/w cervical and lumbosacral segments