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71 Cards in this Set
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what are some general signs of CNS vs. PNS lesions?
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cognitive impairment, hemiparesis: cerebral cortex lesions
movement disorders, postural instability, rigidity: basal ganglia lesions CN/bulbar palsy: brainstem lesions intention tremor, impaired RAM, ataxic gait: cerebellum lesions localized pain, para/quadriparesis, spasticity, equivocal reflexes, sensory loss below "level", bowel/bladder/sexual dysfunction: spinal cord lesions PNS signs/symptoms, algesias, abnormal sensation: PNS lesions (neuropathies) |
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What are anterior horn cells?
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starting point of PNS
synapse point of corticospinal tracts (UMNs) source of LMN nerve roots which combine in brachial or lumbosacral plexus with sensory fibers to form major peripheral nerves |
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what are mononeuropathies and their signs/symptoms?
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disorders of single peripheral nerves
flaccid paresis areflexia (DTR loss) |
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what are other signs/symptoms of mononeuropathies?
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hypalgesia (reduced pain) or analgesia (insensitivity to pain)
can produce paresthesias (spontaneous sensations) can produce dysesthesias (spontaneous painful sensations) can produce allodynia (conversion of light touch/cool air into painful sensation) can produce hyperalgesia (mild noxious stimuli into exaggerated painful response) can produce hyperpathia (delayed, exaggerated, prolonged pain) |
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What is median nerve mononeuropathy?
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paresis of thumb abduction with thenar atrophy
pain/sensory loss of thumb, 2nd, 3rd & lateral 1/2 of 4th finger no DTR loss ex: carpal tunnel syndrome (worse at night, awaken patient) |
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what is the Tinel sign?
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percussing wrists generates electric sensations shooting from wrists into palms/fingers.
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what is ulnar nerve mononeuropathy?
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paresis of finger & thumb adduction (claw hand)
pain/sensory loss of 5th and medial 1/2 of 4th finger no DTR loss atrophy of hypothenar eminence (5th finger base) causing flexion/abduction of 4th/5th finger (benediction sign) ex: prolonged leaning on elbows (watchmakers, draftsmen) |
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what is radial nerve mononeuropathy?
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paresis of wrist, thumb, fingere extensors (wrist drop)
loss of brachioradialis DTR (triceps DTR spared) pain/sensory loss of dorsum of hand ex: "Saturday night palsy": intoxicated pts leaning on upper arm for hours |
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what is femoral nerve mononeuropathy?
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paresis of knee extensors
loss of quadriceps (knee) DTR pain/sensory loss of anterior thigh, medial calf |
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what is sciatic nerve mononeuropathy?
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motor paresis of ankle dorsiflexors/plantarflexors (flail ankle)
pain/sensory loss of butt, lateral calf and most of foot loss of Achilles (ankle) DTR ex: "toilet seat neuropathy": intoxicated pts sitting on toilet for hours |
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what is fibular nerve mononeuropathy?
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motor paresis of ankle dorsiflexors/evertors (foot drop)
pain/sensory loss of dorsum of foot and lateral calf no DTR loss AKA foot drop ex: prolonged leg crossing, lower leg cast pushing against head of fibula, lower knee injuries |
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what is mononeuritis multiplex?
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simultaneous/stepwise development of multiple, geographically separated peripheral mononeuropathies
often with cranial nerve injuries manifestation of systemic illness, leprosy |
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what are neuropathies?
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AKA polyneuropathies
generalized symmetric involvement of all peripheral nerves |
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how are neuropathies divided into categories?
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myelin (demyelinating) vs. axons (axonopathies)
or sensory vs. motor vs. mixed sensorimotor |
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what are signs of sensory neuropathy?
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stocking-glove hyperalgesia:
numbness, paresthesias or burning in fingers/toes can provoke leg movements (e.g. restless leg syndrome) |
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what are signs of motor neuropathy?
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distal limb weakness
impairment of fine motor actions muscle atrophy/flaccidity DTR loss: brachioradialis/Achilles before more proximal sites |
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what are signs of sensorimotor neuropathies?
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combination of sensory and motor neuropathies.
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what is Guillian-Barre Syndrome?
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acute inflammatory demyelinating polyradiculoneuropathy (AIDP)
postinfectious demyelinating polyneuropathy can follow: viral upper respiratory disease GI (Campylobacter jejuni) illness (leads to worse cases) Lyme disease |
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what are signs/symptoms of GBS?
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paresthesias/numbness in fingers/toes
then flaccid paresis of feet/legs with absent knee/ankle DTRs then weakness/areflexia in hands/arms can develop resp insufficiency from phrenic/intercostal nerve involvement (requires intubation) can develop bulbar palsy, facial weakness, ocular immobility from CN involvement CSF shows elevated protein/few WBCs (albumino-cytologic dissociation) |
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what is course and treatment for GBS?
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peaks in weeks
usually resolves almost completely in 3 months after PNS myelin regeneration plasmapheresis: extracts inflammatory mediators reducing paresis IVIG: blocks antibodies at NMJ steroids do not help |
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Does GBS typically involve altered mental status? What are possible causes? What treatment considerations should be kept in mind?
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No, because it is a PNS disease?
life-threatening complications involving CNS: cerebral hypoxia from respiratory insufficiency "steroid psychosis" from inappropriate high dose steriod use hydrocephalus from impaired high protein CSF reabsorption hyponatremia from IADH sleep deprivation Avoid BDZs/antipsychotics which could depress respirations |
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what are signs of CNS injury?
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UMN involvement:
spastic hemi/paraparesis no fasciculations hyperactive DTRs with Babinski sign hemi/para sensory loss |
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what are signs of PNS injury?
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LMN involvement:
flaccid distal paresis with atrophy fasciculations present hypoactive DTRs without Babinski sign sensory loss in hands/feet |
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what are key differences between CNS and PNS demyelinating diseases?
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oligodendrocytes (CNS myelin source) do not regenerated damaged neurons: impairment permanent
Schwann cells (PNS myelin source) regenerate damaged myelin: patients recover exception: patients recover from MS (CNS demyelinating disease) likely from resolution of myelin inflammation vs. regeneration (does not occur later with large areas of CNS damage) |
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what is diabetic neuropathy?
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stocking-glove sensory loss
loss of DTRs in ankles then knees possible pain/burning sensations, especially in feet ANS involvement: erectile dysfunction, bladder muscle contraction, GI immobility) |
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How do you treat diabetic neuropathy?
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Opioid narcotics
AED meds: gabapentin, pregabalin (Lyrica) TCAs (low dose) SNRIs: duloxetine (Cymbalta) capsiacin cream |
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what are signs of acute vs. chronic heavy metal poisoning?
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fatal GI symptoms and CV collapse in acute poisoning
polyneuropathy, dermatologic abnormalities, mental changes in chronic poisoning |
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what are signs of lead poisoning?
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inattention, learning disabilities, poor school performance in children
seizures, MR at high concentrations in children mononeuropathies in adults |
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what are signs of arsenic poisoning?
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anorexia
malaise distal neuropathy resembling GBS Mees lines (white bands) on fingernails hyperpigmentation hyperkeratosis |
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what are signs of mercury poisoning?
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neuropathy
CNS deficits: cognitive deficits, ataxia, dysarthria, visual field changes black/dark blue line along gums below teeth (inorganic/industry mercury causes kidney injury, mild cognitive impairment) |
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what are signs of thallium poisoning?
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neuropathy, possibly painful
alopecia |
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what is the neuropathic effects of aging?
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sensory loss akin to subtle sensory neuropathy:
absent ankle DTRs loss of some joint position & most vibratory sense in feet inability to perform tandem (heel-to-toe) gait predisposition to falling |
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what are the neurological diseases associated with vitamin A?
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Vitamin A (e.g. retinol):
deficency: night blindness excess: pseudotumor cerebri, fetal abnormalities |
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what are the neurological diseases associated with vitamin B1?
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Vitamin B1 (thiamine):
deficency: Wernicke-Korsakoff syndrome, Beriberi involves absent DTRs and loss of position sense |
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what is Wernicke-Korsakoff syndrome involve?
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amnesia
dementia cerebellar degeneration sensory neuropathy absent DTRs and loss of position sense |
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what are the neurological diseases associated with vitamin B2?
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Vitamin B2 (riboflavin):
none |
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what are the neurological diseases associated with vitamin B3?
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Vitamin B3 (niacin):
deficiency: pellagra |
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what does pellagra involve?
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dementia
dermatitis diarrhea |
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what are the neurological diseases associated with vitamin B6?
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Vitamin B6 (Pyridoxine):
deficiency: seizures, psychosis excess: sensory neuropathy |
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what are the neurological diseases associated with vitamin B9?
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Vitamin B9 (Folic acid/folate):
deficiency: neural tube defects reduces elevated homecysteine levels |
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what are the neurological diseases associated with vitamin B12?
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Vitamin B12 (cobalamine):
deficiency: Combined system disease |
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what is involved in combined system disease?
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cognitive impairment, sensory loss from demyelination of posterior columns (CNS)
megaloblastic anemia elevated homocysteine/methylmalonic acid levels confirmatory test: Schilling test |
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what are the neurological diseases associated with vitamin C?
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Vitamin C (ascorbic acid):
deficiency: scurvy |
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what are the neurological diseases associated with vitamin E?
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Vitamin E (alpha-tocopherol):
deficiency: ataxia, neuropathy scavenges free radicals |
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what is involved with herpes zoster?
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infection of single nerve root
usually in over 65 or immunosuppressed ugly red painful vesicular eruption occurs in 1st division of trigeminal nerve or other dermatome |
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what is involved in leprosy?
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infection with Mycobacerium leprae
anesthetic hypopigmented patches of skin anesthetic fingers/toes palpable nerves affects cool areas: earlobes, noses, digits |
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what is involved in Lyme disease?
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infection by Borrelia burgdorfei (spirochete: poss false positive syphilis test)
peaks in June to September arthritis malaise low-grade fever cardiac arrhythmias erythema migrans (bull's eye expanding rash) unilateral or bilateral facial nerve palsy possible mild neuropathy to severe GBS like illness possible CNS involvement: H/A, delirium, signs of meningitis/encephalitis CSF: possible pleocytosis, low glucose, Lyme antibodies |
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what is involved in neurologic aspects of AIDS-associated PNS?
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neuropathy: most common complication of late-stage AIDS
insidious distal symmetric (very) painful dysesthesias numbness of soles of feet mild foot/ankle weakness no ankle DTRs associated with high HIV RNA titer, low CD4 count treat as with diabetic neuropathy |
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what is acute intermittent porphyria (AIP)?
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autosomal dominant disorder of porphyrin metabolism:
attacks of quadriparesis attacks of severe colicky abdominal pain possible agitation, delirium, dementia, psychosis dark red urine after exposure to sunlight from excess porphyrins test for urine/serum prophobilinogen/5-aminolevulinic acid (replaced Watson-Schwartz test) excerbated by barbituates, phenytoin |
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what is metachromatic leukodystrophy (MLD)?
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autosomal recessive illness on chromosome 22
CNS demyelination (leukodystrophy) > PNS involvement colored granules in lysosomes of brain, PNS, GI organs decreased arylsulfatase A enzyme activity infants/children: rapidly fatal young adults: "frontal dementia": personality/behavioral changes, cog imp, mood/thought d/o spasticity, ataxia (CNS) neuropathy (PNS) |
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what is solvent-induced encephalopathy?
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exposure to n-hexane, toluene, ethylene oxide, carbon disulfide
neuropathy possible CNS involvement includes: cog impairment, personality changes, inattention depression, H/A, fatigue, psychosis |
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what is the effect of n-hexane?
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recreational inhaling ("glue sniffing")
PNS complications including polyneuropathy |
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what is the effect of toluene?
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recreational inhaling of gases from spray paint/marker pens
CNS damage: personality changes, psychosis, cog impairment possible subcortical dementia: gait ataxia without language impairment spasticity visual impairment evaluate with MRI |
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what is the effect of nitrous oxide?
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profound neuropathy
combined system disease from B12 deficiency (NO inactivates B12) |
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what is ciguatera fish poisoning?
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prolonged voltage-gated sodium channel opening in nerves/muscles
nausea/vomiting acute painful neuropathy: paresthesias, loss of sensation, pain cold allodynia: cold objects misperceived as hot caused by eating grouper, barracuda, red snapper |
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what is tetrodoxin poisoning?
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numbness around mouth/face
flaccid quadriparesis respiratory failure caused by eating puffer fish, some crabs |
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what is amyotrophic lateral sclerosis (ALS)?
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AKA Lou Gehrig disease
motor neuron disease: both UMN/LMN degenerate sparing other facilities 5-10% pts have autosomal dominant inheritance 2% have mutation of chromosome 21: assists detox of superoxide free radicals (accelerates neuron aging/death) glutamate excitotoxcity leads to cell death by apoptosis develops at median age of 66 yo weakness atrophy fasciculations in arm/leg with brisk DTRs, Babinski signs asymmetric spread to other limbs, face, pharynx, tongue leads to bulbar palsy: dysphagia/dysarthria cognitive ability spared treat with riluzole (Rilutek): slows progress poss by reducing glutamate excitotoxicity 80% die within 5 years |
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what is involved in childhood-onset motor neuron diseases?
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extensive loss of anterior horn cells
preserved cognitive function/extraocular muscle movement in infants (Werdnig-Hoffmann disease) in children (Kugelberg-Welander disease) these are varieties of spinal muscular atrophy: progressively severe flaccid quadriparesis atrophic areflexic muscles with fasciculations autosomal recessive due to chromosome 5 mutation |
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what is involved in poliomyelitis?
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infection of motor neurons of anterior horn cells of spinal cord & lower brainstem (bulb)
acute febrile illness with LMN signs: asymmetric paresis, fasciculations, no DTRs bulbar variety develop throat/chest muscule paralysis oculomotor, bladder, bowel & sexual function spared cognitive function spared |
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what is post-polio syndrome?
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patients experiencing polio in childhood
weakness, fasciculations in middle age rare syndrome if it exists at all can be accounted for by lumbar spine degeneration |
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what are benign fasciculations?
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innocuous muscle twitches
usually caused by stress, excessive exertion, caffeine, insecticides no weakness, atrophy, abnormal reflexes last only for days-weeks |
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what is myokymia?
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benign eyelid muscle (obicularis oculi) twitching
caused by lack of sleep, excess caffeine, other irritants unilateral, don't force eyelid closed, last 1 sec at most (otherwise may be facial dyskinesia: blepharospasm, hemifacial spasm, tardive dyskinesia) |
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what is involved in cervical spondylosis?
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chronic age/occupational degenerative condition
bony proliferation -> vertebral foramina -> damage to cervical nerve roots: neck pain arm/hand sensory/loss, paresis, atrophy, hypoactive DTRs, fasciculations (LMN damage) -> spinal cord stenosis: myelopathy with leg weakness, spasticity, hyperreflexia, babinski signs (UMN damage) |
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what is involved in lumbar spondylosis?
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chronic age/occupational degenerative condition
bony proliferation -> vertebral foramina -> lumbar root compression: lower back pain chronic buttlock pain radiating down posterior leg (sciatica) leg/feet sensory loss/paresis, atrophy, hypoactive DTRs, fasciculations (LMN damage) -> spinal cord stenosis: myelopathy possible leg pain/weakness only with walking (neurogenic claudification) possible forward slip of adjacent lumbar vertebrae/L5 of sacrum (spondylothesis) |
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what is the difference between cervical/lumbar spondylosis and ALS?
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ALS does not have:
neck/lower back pain sensory loss absence of abnormalities to facial, pharyngeal and tongue muscles |
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what is involved in herniated disks?
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gelatinous checker-shaped shock absorbers
pressing against nerve roots typically in cervical or lumbosacral spine acute neck/lower back pain pain may radiate down nerve root's distribution possible sensory loss or weakness, DTR loss 90% of lumbosacral occur at L4-5 or L5-S1 space leg pain worsened by elevating straight leg (Lasegue sign) also worsened by straining at stool, coughing, sneezing 20% of pts with herniated disk on MRI asymptomatic |
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what is the difference between an L4-L5 vs L5-S1 herniated disk?
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L4-L5 herniation: compresses L5 nerve root -> ankle DTR intact
L5-S1 herniation: compresses S1 nerve root -> loss of ankle DTR |
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what is the cauda equina?
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bundle of lumbar and sacral nerve roots in lower spinal canal
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what is involved in cauda equina syndrome?
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LMN paresis of one or both legs
perineal ("saddle area") pain/anesthesia incontinence sexual dysfunction caused by large lumbar disk herniations |
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How do you treat herniated disks?
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conservative treatment for most:
nonopioid analgesics superficial heat reduction in physical activity 90% resolve in 6 weeks |
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When is surgery indicated for herniated disks?
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spinal cord compression
cauda equina syndrome refractory objective symptoms & signs of nerve root compression neurologic deficits severe disability |
