disease of peripheral nerves - waldron Flashcards
what is peripheral neuropathy
refers to many conditions that involve damage to the peripheral nervous system
symptoms depend on the type of nerve fibers affected and the type and severity of damage
how is nerve signaling in neuropathy disrupted
loss of signals normally sent (broken wiring)
inappropriate signaling when there shouldn’t be any (like static)
error that distort the messages being sent (like a wavy television picture)
what is motor nerve damage
usually associated with muscle weakness - other symptoms include painful cramps, fasciculations, muscle atrophy
what is sensory nerve damage
various symptom patterns
loss of vibratory sense, stocking glove sensation, loss of reflexes, loss of position sense, loss of temperature sensation, pain
what is autonomic nerve damage
aka small-fiber neuropathies
common symptoms: excess sweating, heat intolerance, inability to expand and contract small blood vessels regulating blood pressure, gastrointestinal symptoms
what is a mononeuropathy
only one nerve affected
what is it called when several discrete nerves are effected
multiple mononeuropathy or mononeuritis multiplex
what is polyneuropathy
multiple nerves diffusely affected
what is a plexus effect called
plexopathy
what is a radiculopathy
when a nerve root is affected
what are symptomatic acquires causes of peripheral neuropathy
Physical injury (trauma)
Diabetes
vascular and blood problems
systemic autoimmune diseases
triggered autoimmune
kidney and liver disorders
nutritional/vitamin imbalances, alcoholism, exposure to toxins
cancer/benign tumors
chemotherapy/radiation
infections
what is the most common cause of single nerve injury
physical injury (trauma)
what is the leading cause of polyneuropathy in the US
diabetes - 60-70% of patients
what is a genetic cause of peripheral neuropathy
Charcot-Marie- Tooth - rare but one of the most common INHERITED neurological disorder
no cure - supportive - permanent damage to nerves
what is the most common INHERITED neurological disorder
Charcot-Marie-Tooth
how is peripheral neuropathy evaluation
medical history
physical with full neurological exam
body fluid tests: blood work/CSF
genetic tests
what are important history events for peripheral neuropathy examination
work, travel, toxin exposure, ETOH, history if infection
what are unilateral defects typically caused by
mononeuropathies or plexopathies such as focal disorders
what are physiologic tests of nerve functions
nerve conduction velocity (NCV) and EMG
what is NCV assessing
nerve conduction velocity - signal strength and speed
what is an EMG assessing
electrical activity rest/contraction
what are neuropathology tests of Nerve appearance
Neurodiagnostic skin biopsy and nerve biopsy
what is the gold standard for diagnosing small fiber neuropathies
Neurodiagnostic skin biopsy
what is Autonomic testing for peripheral Neuropathy
QSART (small fiber neuropathies) - sweat ability, ACH
what are radiology imaging tests used for peripheral neuropathies
MRI, CT and muscle and nerve ultrasound
what is MRI looking for when evaluating for peripheral neuropathies
looking for compression/mass/soft tissue structural
What is a CT looking for when evaluating for peripheral neuropathies
looking for mass/solid tissue structural I.e. spinal stenosis
how is peripheral neuropathies managed?
Addressing neuropathies cause
specific symptoms can usually be improved
TENS
medications
surgery
How are you able to address the cause of neuropathy
glucose control, smoking cessation, diet, exercise
plasmapheresis, immunoglobulins for inflammatory/autoimmune source
how are specific symptoms managed for peripheral neuropathies
motor -orthotic, mechanical aids
autonomic - acupuncture, massage, CBT/psychotherapy, herbal remedies
Sensory - behavioral strategies
what is the best treatment for peripheral neuropathy
the best treatment is prevention - unnecessary procedures should be avoided
what is the prognosis of peripheral neuropathy
long term prognosis and complications vary; depending on underling cause, its control and which nerves have been damaged
some symptoms improve with time
some may have permanent damage or may have symptoms progressively worsen with time
rarely fatal
What is CRPS
complex regional pain syndrome
chronic >6 months) pain condition that most often affects one limb usually after an injury
how is CRPS characterized
by prolonged or excessive pain and changes in skin color, temperature, and/or swelling in affected area
what are the types of CRPS
CRSP-1
CRSP - 2
what is CRPS-1
WITHOUT confirmed nerve injury (previously known as reflex sympathetic dystrophy syndrome)
what is CRPS-2
with an associated, CONFIRMED nerve injury (previously known as causalgia)
what is the epidemiology of CRPS
W>M
any age with peak at 40yo
(rarely in elderly, very few children <10yo, almost no children <5yo)
what population is CRPS more common in
patients with other inflammatory and autoimmune conditions such as asthma
what is the pathophysiology of CRPS
> 90% triggered by clear history of trauma or injury
vascular effects
immune system effects
may be influenced by genetics
what are the most common triggers of CRPS
fractures/sprains/strains/limb immobilization
soft tissue injuries
surgery/minor medical procedures
what is the immune systems effects causing CRPS
high levels of cytokines=redness, swelling and warmth
what vascular effects cause CRPS
possible ischemia of deeper tissues causing muscle and pain/damage
what are the typical ‘insults’ leading to CRPS
infection
blood vessel inflammation
entrapment of nerve causing internal injury
what is the key symptom of CRPS
prolonged sever pain, may be constant
often described as “burning”, “pins and needles”, or “squeezing” sensation of affected limb
pain may spread to entire arm or leg, even though injury might have only involved a finger/toe
often increased sensitivity in affected area
what are possible presentation of CRPS
may experience changes in skin temperature, skin color or swelling of affected limb
may feel warmer/cooler compared to opposite limb
may change color, becoming blotchy, blue, purple, pale or red
what is the evaluation of CRPS
no specific test that can confirm CRPS
clinical diagnosis
distinguishing feature of CRPS is that of an injury to affected area
MRI or triple-phase bone scan may help confirm diagnosis
what is CRPS often associated with that can be seen on testing
excess bone resorption but may be observed in other illnesses as well
what is the treatment of CRPS
Rehabilitation and PT
psychotherapy
sympathetic nerve block
surgical sympathectomy
intrathecal drug pumps
spinal cord stimulation
neural stimulation (transcranial magnetic stimulation, or rTMS)
Medications
what medications are often used in the treatment of CRPS
bisphosphonates
NSAIDs
Corticosteroids
neuropathic pain meds
botox
opioids
NMDA receptor antagonists
topical anesthetics
what is the prognosis of CRPS
outcome is highly variable
younger adults, children and teens have better outcomes
some patients experience severe pain and disability despite treatment
what is vitamin B 12
a water soluble vitamin important in cellular metabolism and maintenance of the integrity of the nervous system
important in synthesis of DNA and cell division
what is deficiency in Vitamin B12 associated with
impaired erythropoiesis and nervous system demyelination, which account for most of its clinical manifestations
what is the most common etiology of vitamin B12 deficiency
lack of intrinsic factor (pernicious anemia), a common finding in the elderly
what are other etiologies of B12 deficiency/neuropathy
autoimmune
malabsorption
dietary insufficiency
what is the epidemiology of B12 Neuropathy
common in elderly regardless of cause
patients with anemia
patient with macrocytosis
pernicious anemia
overall incidence is rare
what is the pathophysiology of B12 neuropathy
dietary B12 binds to R-factor protein in saliva
in small intestines - b12 cleared from R-factor by pancreatic enzymes
b12 then binds to intrinsic factors secreted by gastric parietal cells
complex binds to receptor in ileum which allows for absorption
once absorbed b12 integrated into neurologic and hematologic pathways
what is seen on the H&P for B12 neuropathy
pallor, fatigue - consistent with microcytic anemia
dementia, mental status, peripheral neuropathy, ataxia/loss of proprioception on neuro exam
what bloodwork is run with vitamin B12 neuropathies
CBC with peripheral smear
serum B12 folate
MMA and Hemoysteine
if the GI or dietary source is negative on evaluation of B12 neuropathy what needs to be considered
Autoimmune source - blood work for anti-intrinsic facrot antibodies
if there is an autoimmune source with B12 neuropathy what will be present
pernicious anemia
what is the management of B12 neuropathy
replace missing B12 pending etiology: duration and route vary
what patient populations require routine monitoring with B12 supplimentation
Crohn’s disease and Celiac Disease
what are complications of B12 neuropathy if undiagnosed
heart failure
severe disabling neurological deficits
increased risk for gastric cancer
increased risk of autoimmune disease
what is Guillain-Barre syndrome
rare neurological disorder in which the body’s immune system mistakenly attacks PNS
severity can range from very mild with brief weakness to nearly devastating paralysis
what is the epidemiology of Guillain-Barre syndrome
M=F
strike at any age (more frequent in adults and older people)
can be life-threatening - potentially interfering with breathing, blood pressure and/or heart rate
what is the pathophysiology of Gillain-Barre Syndrome
exact cause unknown
most cases usually start a few days or weeks following a respiratory or gastrointestinal viral infection
occasionally surgery is a trigger
what is the Molecular mimicry/innocent bystander therory
mechanism theories of guillian-barre syndrome
when preceded by viral or bacterial infection, infecting agent has changed chemical structure of some nerve and the nerves are now identified as foreign bodies and mistakenly attacked
virus itself makes immune system itself less discriminating and no longer able to recognize its own nerves.
what is the campylobacter theory
mechanism theory of guillain-barre syndrome
antibodies to fight Campylobacter jejuni infection attack axon in motor nerves, causing acute motor axonal neuropathy
some campylobacter molecules resemble molecules in patients nerve axons, so their antibodies also attack the look-alike axons
what is the presentation of Guillain-Barre syndrome presentation
symmetric weakness is the major symptom that prompts most patients to seek medical attention and is most characteristic of the syndrome
weakness may first appear as difficulty climbing the stairs or with walking - symptoms often affect arms, breathing muscles, or even the fact.
where do symptoms typically start
the upper body and move down to the legs
what is the progression of symptoms
they can increase in intensity over a period of hours, days, or weeks until certain muscles cannot be used at all
when sever, the person is almost totally paralyzed
what are key diagnostic findings for Guillain-Barre syndrome
recent onset (days to at most 4 weeks of symmetric weakness)
abnormal sensation
absent or diminished deep tendon reflex
recent vital infections or diarrhea
elevated CSF protein without elevated cell count
abnormal nerve conduction velocity findings
what are key points to presentation of Guillain-Barre syndrome
Symmetry and speed
what are the types of Guillain-Barre syndrome
Acute inflammatory demyelinating polyneuropathy (AIDP)
acute motor axonal neuropathy (AMAN)/ Acute motor-sensory axonal neuropathy (AMSAN)
Miller-fisher syndrome
chronic inflammatory demyelinating polyneuropathy (CIDP)
Multifocal motor neuropathy
what is acute inflammatory demyelinating polyneuropathy (AIDP)
most common type seen in the US
immune response damages the myelin coating and interferes with the transmission of nerve signals
what is AMAN/AMSAN
Acute motor axonal neuropathy/acute motor-sensory axonal neuropathy
axon themselves are damaged by the immune response
what is Miller-Fisher syndrome
rare, acquired nerve disease; most have a unique antibody
characterized by abnormal muscle coordination with poor balance and clumsy walking, weakness or paralysis of the eye muscles and absence of tendon reflexes. symptoms may follow viral illness
additional symptoms - generalized muscle weakness and respiratory failure
what is CIDP
chronic inflammatory demyelinating polyneuropathy
weakness that can recur, repeatedly, over the course of years
what is multifocal motor neuropathy
affects many different muscles in a small part of a limb/s
usually the symptoms are more severe on one side of the body
what is the acute treatment of Guillain-Barre syndrome
plamsa exchange
High-dose immunoglobulin therapy (IVIg)
Both are equally effective if started within two weeks of onset of symptoms
what are other acute treatments of Guillain-Barre
corticosteroids
supportive care
close monitoring - breathing, cardiac, swallowing
what are the rehabilitation treatments for guillain-barre syndrome
PT - strength may not return uniformly
OT
Vocational therapy - evaluate need for implement assistive devices and other adaptive equipment and technology
when assessing for GBS what is important to ask about
any recent viral infection or diarrhea
why are patients with GBS admitted to the ICU
with concerns for respiratory failure
