Quiz 2 Flashcards
do we expect to see UMN or LMN signs with PNS injuries?
LMN signs
what does the endoneurium surround?
individual axons
what does the perineurium surround?
fascicles (bundles of neurons)
what does the epineurium cover?
bundle of fascicles
what is the point of dynamic protective mechanisms in nerve mobility?
provide adequate blood flow for nutrition, oxygen, and removal of waste
movement of the nerve against adjacent structures allows for health of the nerve
t/f: axoplasm flows easily throughout the axon with movement
true!
what if dynamic protective mechanisms fail?
immobility=numbness
try gentle lengthening and shortening of the nerve
what do nerves look like in resting?
folding with wrinkles in endoneurium
stretch gets rid of wrinkles
what are the sensory signs of peripheral nerve injury?
decreased/lost sensation
abnormal sensations (dysesthesia, algesia, hyperalgesia)
what are the motor signs of peripheral nerve injury?
paralysis/paresis
muscle atrophy (neurogenic)
fasciculation/fibrillation
what are the autonomic signs of peripheral nerve injury?
single nerve severance signs are less severe
multiple nerves damaged-difficulty regulating BP, HR, sweating, b/b fxns, impotence
what are the trophic signs of peripheral nerve injury?
abnormalities in the lesion of the nerve injury
what are the trophic changes in muscles with peripheral nerve injury?
muscle atrophy
what are the trophic changes in skin with peripheral nerve injury?
shiny, dry, pigmentation changes
what are the trophic changes in nails with peripheral nerve injury?
brittle
what are the trophic changes in subcutaneous tissue in peripheral nerve injury?
thicken, ulceration, poor healing of wounds
what are the trophic changes in joints in peripheral nerve injury?
neurogenic damage from lack of movement
what are the classifications of peripheral nerve injuries?
mononeuropathies, multiple mononeuropathies, and polyneuropathies
what are the 3 mononeuropathies?
1) truamatic myelinopathy (neuropraxia)
2) traumatic axonopathy (axonatmesis)
3) traumatic severence (neurotmesis)
what is the usual cause of all 3 mononeuropathies?
trauma
what is the pathology of neuropraxia?
demyelination
what is the pathology of axonatmesis?
axon damage
what is the pathology of neurotmesis?
axon and myelin degeneration
what is multiple mononeuropathy?
sporadic, non symmetrical pattern of single neuropathy in many places
what is polyneuropathy?
symmetric
often complication of diabetes
what is neuropraxia?
loss of myelin at the site of injury with no axon damage
temporary impairment of nerve conduction (recovery within hours/weeks)
complete recovery via re-myelination
neuropathic pain
impaired discriminitive touch, proprioception, motor, and DTRs
how long does recovery in neuropraxia take?
hours to weeks
what is the least severe mononeuropathy?
neuropraxia
what axons are affected first in neuropraxia?
large myelinated axons
is there complete recovery with neuropraxia?
yes!
what is the prognosis for neuropraxia?
good, bc there is complete and rapid recovery via re-myelination
what is axonotmesis?
axon and myelin sheath damage with intact endo, peri, and epineurium
Wallerian degeneration at/below level
impaired discriminitive touch, proprioception, motor, DTRs, and autonomic (if severe enough)
decreased nerve conduction velocity and amplitude
complete recovery (1 mm/day of growth)
are the endo, peri, and epineurium intact in axonotmesis?
yes!
what size axons are affected in axonotmesis?
all sizes
is there complete recovery with axonotmesis?
yes!
how long does recovery take in axonotmesis?
1 mm/day (1 inch/month)
what is a common cause of neuropraxia and axonotmesis?
entrapment or mechanical contriction
what does myelin damage lead to?
inflammation in the NS, ectopic foci, and decreased nerve conduction velocity
what is Tinnel’s sign?
oversensitivity of the nerve to mechanical stimuli
tapping a superficial nerve may elicit pain
what is neurotmesis?
axon, myelin sheath, and CT damaged
wallerian degeneration
incomplete recovery
no nerve conduction
neuroma-hypersensitivity
from severe trauma (gunshot, stabbing)
why is there incomplete recovery in neurotmesis?
no covering is guiding the axon growth
what are common UE mononeuropathies?
axillary neuropathy
“saturday night” or “honeymooner’s” palsy (radial nerve)
crutch palsy (radial nerve or brachial plexus)
carpal tunnel syndrome (median nerve)
cubital tunnel syndrome (ulnar nerve)
what are common LE mononeuropathies?
femoral neuropathy
sciatic neuropathy
peroneal nerve palsy
obturator nerve palsy
morton’s neuroma-wrist drop from radial nerve palsy, atrophy of instrinsic muscles of the hand
what does peroneal nerve palsy cause?
foot drop
what does Morton’s neuroma cause?
wrist drop and atrophy of intrinsics
what nerve is affected in Morton’s neuroma?
radial nerve
what is sciatic neuropathy?
compression/irritation of the sciatic nerve causing motor and sensory symptoms
what are some causes of sciatic neuropathy?
herniated disc
spinal stenosis/spondylosis
piriformis syndrome
what are the motor symptoms associated with sciatic neuropathy?
weakness (specific to the supplied muscles)
severe cramping
reduced DTRs in L4-S1
what are the sensory symptoms associated with sciatic neuropathy?
numbness, burning, tingling (specific to the involved dermatome)
sharp shooting pain
what makes sciatic neuropathy worse?
prolonged sitting, standing, sneezing, coughing
what are multiple mononeuropathies?
involvement of 2/more nerves in dif parts of the body
asymmetric, random presentation of symptoms
occurs with ischemic nerve damages caused by DM or vasculitis (can occur with RA, lupus, and HIV as well)
are multiple mononeuropathies symmetrical or asymmetrical?
asymmetrical
what are polyneuropathies?
symmetric involvement of sensory, motor, and autonomic fibers that progresses distal to proximal in glove and stocking pattern
what axons are affected first in polyneuropathy?
large myelinated
what neuropathy can be metabolic, hereditary, inflammatory, idiopathic, or toxic (alcoholism)?
polyneuropathy
what is the most common polyneuropathy?
diabetic polyneuropathy
what are some polyneuropathies?
diabetic polyneuropathy
GBS
hereditary motor and sensory polyneuropathy (HMSN)-Charcot Marie Tooth disease
chronic inflammatory demyelinating polyneuropathy (CIDP)
idiopathic polyneuropathy
what is the difference b/w GBS and CIDP?
s/s are very similar but CIDP is more chronic than GBS and can take years to progress and recover
what is diabetic polyneuropathy?
a metabolic disorder compromises microvascular blood supply causing oxidative stress, autoimmunity, and chemical disturbances
what is the damage to structures in diabetic polyneuropathy?
demyelination and axonal damage=orthostatic hypotension symptoms
greater sensory involvement than motor
glove and stocking pattern of loss
hyporeflexia
why can there be orthostatic hypotension in diabetic polyneuropathy?
bc there is a loss of autonomic regulation of blood flow with the demyelination and axon damage
is there a greater motor or sensory involvement in diabetic polyneuropathy?
sensory
what is the pattern of loss in diabetic polyneuropathy?
glove and stocking
what is Charcot Marie Tooth disease?
hereditary motor and sensory neuropathy (HMSN) causing muscle atrophy and paresis distal to the knee and progressing to hands
what is the sensory involvement associated with Charcot Marie Tooth disease?
↓ thermal and pain sensation
neuropathic pain
numbness, tingling, burning-not severe
t/f: with charcot marie tooth disease, there is early inflammation, joint dislocation/subluxation, pathological fractures of the foot
true
what are the symptoms of Charcot Marie Tooth disease?
midfoot swelling (one of the most prominent signs)
shorter 1st metatarsal bone
laterally curved foot
uni or bilateral
hammer toe
high arch/flat foot
what are the neuromuscular junction disorders?
myasthenia gravis and botulism
what is myasthenia gravis?
decreased amplitude of AP on EMG
repetative use-weaker muscles
what is botulism?
acute, progressive weakness
loss of stretch reflexes
usually therapeutically used to decrease spasticity
what are myopathies?
degeneration of muscle fibers leading to muscle atrophy and weakness
is there greater weakness proximally or distally with myopathies?
proximally
is there sensory or autonomic involvement in myopathies?
nope!
what are the 3 myopathies?
1) Duchenne’s muscular dystrophy
2) dermatomyositis
3) polymyositis
what are the immune related myopathies?
dermatomyosititis and polymyositis
what are the 2 pediatric plexus disorders?
Erb’s palsy and Klumpke’s palsy
what roots are involved in Erb’s palsy?
C5-6
what is the pathophysiology of Erb’s palsy?
fall or traumatic birth
what roots are involved in Klumpke’s palsy?
C8-T1
what is the pathophysiology of Klumpke’s palsy?
traction of abducted arm
may present with Horner’s disease is severe
is the neurologic level above or below the vertebral level?
below
what vertebral bodies are associated with C8 SC segment?
C6-7
what vertebral bodies are associated with T1 SC segment?
C7-T1
what vertebral bodies are associated with T10-11 SC segment?
T9
what vertebral bodies are associated with L2-5 SC segment?
T12
what vertebral bodies are associated with S1-5 SC segment?
L1
what are the nerve roots of the diaphragm?
C3-5
if there is a lesion above C4, is there independent breathing?
no