Peripheral Neuropathies 1 Flashcards
1
Q
Wallerian degeneration
A
distal part of a cut n. dies and macrophages destroy it
2
Q
axonal degeneration
A
long n. at the ends start to die and degenerates backward form the end
3
Q
small v. large fiber nn.
A
small fiber: poorly myelinated, primarily sensory and autonomic; symptoms = burning, tingling, numbness, pain
large fiber: heavily myelinated; primarily motor and sensory; symptoms = weakness, vibratory and position sense loss, numbness, areflexia
4
Q
peripheral symmetric polyneuropathy
A
- usually affects longest nn. first; start in feet and then works up to hands; glove/stocking distribution; ex: diabetes
5
Q
motor neuropathies
A
- Guillain Barre syndrome and motor neuron disease most commonly seen
- also includes porphyria and tick paralysis (more in western US like Rocky Mt. area)
6
Q
S&S of peripheral neuropathy
A
- weakness - areflexia
- cramps - ataxias
- deformities - numbness
- pain - spasms
- trophic changes - autonomic dysfunction
- S&S will depend on the nn. involved
7
Q
sensory +/- autonomic neuropathies
A
- diabetes mellitus = #1 risk factor in US
- amyloid
- inherited
- thallium poisoning
- alcohol = #2 risk factor
- leprosy –> depends where you practice; would see it mostly among immigrants
- carcinoma
- pyridoxine –> too much can damage nn. but deficiency can also cause n. damage
8
Q
neuropathy symptom terminology:
hypesthesia; hyperesthesia; dysesthesia; paresthesia
A
hypesthesia = decreased sensation hyperesthesia = increased sensation dysesthesia = unpleasant, abnormal sensation produced by normal stimulus paresthesia = perverted, abnormal sensation like burnin, prickling, formication (crawling)
9
Q
What are the 2 cranial neuropahies?
A
- Guillain-Barre syndrome
- diphtheria
10
Q
Examples of autonomic neuropathies? (5)
A
- diabetes mellitus
- amyloid
- Guillain-Barre (not sure why it’s also listed as cranial)
- porphyria
- thallium poisoning –> rare but could be environment/work-related toxicology as an etiology
11
Q
mononeuropathy multiplex examples? (6)
A
- diabetes mellitus
- vasculitis = rheumatoid arthritis, polyarteritis nodosa
- trauma
- plasma cell dyscrasia
- leprosy
- sarcoidosis
12
Q
palpably enlarged nn. - possibly causes/diseases associated? (5)
A
- inherited disease like charcot marie tooth or neurofibromatosis
- leprosy
- amyloid
- acromegaly
- chronic inflammatory demyelinating polyneuropathy
13
Q
Guillain-Barre syndrome
A
- acute idiopathic inflammatory polyneuropathy
- primarily demyelinating motor polyneuropathy
- ascending paralysis: goes from legs up to arms then breathing mm./nn.
- may begin cranially
- happens more in spring and fall
- unknown etiology but thought to be triggered by infectious agents or cancers -> something triggers an autoimmune response
14
Q
GB possible etiologies
A
- viral illness like respiratory or GI
- CMV, EBV, HIV
- mycoplasma
- campylobacter jejuni –> causes special kind of GB that attacks the myelin and takes longer recovery time
- lymphoma
- vaccines/immunizations
15
Q
GB pathologies
A
- lymphocytic infiltration
- segmental demyelination
- axonal degeneration
- can start w/ ill-defined back pain and tingling; biggest feature = weakness usually ascending
- axon can be damaged if not dx or tx ASAP; want to catch GB in the demyelination phase = faster recovery
16
Q
GB clinical features
A
- paresthesias: tingling, ill-defined back pain
- weakness
- areflexia: starts in ankles and works up
- facial diplegia - both sides of face get weak
- autonomic instability: pts in ICU; could induce heart block
17
Q
ddx for Guillain-Barre
A
- poliomyelitis: very unlikely in US but it’s asymmetric weakness
- myelitis: inflamed spinal cord so should have hyperreflexia not areflexia like GB
- diphtheria
- tick paralysis: geographically unlikely
- heavy metal poisoning
- botulism: can cause weakness and autonomic issues but usually starts cranially
- toxin
- porphyria
- HIV
- **overall the 2 most likely are GB and myelitis and they can be differentiated by the reflexes; GB = areflexia and myelitis = hyperreflexia
18
Q
GB workup/dx procedure
A
- H&P; lumbar puncture, EMG, serology, toxicology
- LP –> looking for normal cell count and high protein = cytoalbuminal dissociation
- EMG –> n. conduction part and transmission part; in GB the transmission slows down; you would also do a m. biopsy
19
Q
GB tx
A
- supportive care: prevent bed sores, DVTs, m. atrophy, pneumonia, etc.; thinking of all the complications and how you can prevent them
- plasmapheresis: take the proteins out of the blood and give the blood back to pt w/o the antibodies
- IV IgG: blood donor then take IgG out of the donor blood and give to pt; floods the system w/ antibodies and the immune system gets overloaded and slows down its response
- NEVER USE STEROIDS!!
20
Q
GB prognosis
A
- mortality = 5% but 20% can be left w/ neurological deficits
- poor outcome predictors = older age, rapid onset, ventilator use, severely reduced distal cMAP on EMG
- best to catch GB in the demyelination phase; better prognosis the earlier you catch it
21
Q
uremic polyneuropathy
A
- most common complication of chronic renal failure
- usually painless, progressive, symmetric sensorimotor peripheral neuropathy
- can be burning, cramping, crawling, itching, creeping which is worse at night; “restless legs”
- caused by diabetes, HTN; accumulation of 300-2000MW toxins
- tx = symptomatic (dialysis) and best = renal transplant - nothing beats a real kidney, not even dialysis
22
Q
alcoholic polyneuropathy
A
- 2nd most common cause of neuropathy
- pathogenesis = direct toxic effect or nutritional (B1, B3, B6, B12, folic acid, zinc)
- symmetric sensorimotor polyneuropathy
- tx = stop drinking and get proper nutrition
23
Q
diabetic neuropathy: what type of neuropathy does it fall into?
A
- mononeuropathy
- mononeuropathy multiplex
- symmetric sensorimotor polyneuropathy
- autonomic
- thoracoabdominal radiculopathy
- amyotrophy
- basically it can be anything!
24
Q
DM as mononeuropathy & mononeuropathy multiplex
A
- cause = compression or infarct (occlusion of vasa nervorum [blood vessels for nn.]
- CN III, VI, VII can all be affected; CNVII most common
- peripheral nn. = femoral, sciatic, peroneal, radial, ulnar, median
25
DM as symmetric sensorimotor polyneuropathy
- starts as glove-stocking neuropathy
- small fiber findings are usually first, then large fiber findings
- diabetic pseudotabes = loss of position sense
26
tx options for dysesthetic peripheral polyneuropathy?
- antidepressants: amitriptyline = one of the oldest, very cheap, major s/e = drowsiness so dose at night; can also cause dry mouth
- lidocaine - can use in patch form
- baclofen - antispasticity
- capsaicin - depletes substance P; topical
- pregabalin = lyrica; pt has to have diabetes for this to be covered
- desipramine, phenytoin, carbamazepine, gabapentin, mexiletine
27
autonomic neuropathies? (3)
- GI and GU symptoms
- impotence
- impaired sweating and vascular function
28
radiculopathy
- thoracic nn. roots most frequently affected
- painful; can resemble herpes zoster pain-wise but won't have the rash
- usually associated w/ poor diabetic control and weight loss
29
amyotrophy
- gradually progressive proximal leg weakness
- painful
- no sensory loss
30
toxic neuropathies = poisonings (6 types w/ assoc. symptoms)
1. arsenic: sensorimotor peripheral polyneuropathy, Mees lines, GI symptoms
2. lead: wrist drop
3. mercury: blindness, peripheral neuropathy
4. thallium: sensory and autonomic findings; alopecia
5. chermotherapeutics: vincristine, cisplatin, Adriamycin
6. isoniazid: anti-TB med; B6 deficiency so when you tx for TB you would give B6 supplement to avoid this complication
31
3 other causes of neuropathies?
- hypothyroidism
- acromegaly
- vasculitis: can see mononeuropathy multiplex or sensorimotor peripheral neuropathy w/ this; caused by polyarteritis nodosa, lupus, drugs, RA, Hep B, scleroderma
32
everything about herpes zoster...go!
- reactivation of VZV
- dermotomal pattern; vesicular eruptions w/ pain, dysesthesias, numbness
- usually immunocompromised and elderly pts
- radicular distribution (T5-T10), cranial nn. (V1, V2, VII)
- can see ramsay hunt syndrome = eruption in the external auditory meatus causing facial paralysis
- tx = analgesics, topical capsaicin, antiviral agents, steroids? <-- probably not knowing Jesper; lidocaine patch can be very effective b/c numbs the area of a small outbreak
33
postherpetic neuralgia
- pain that follows herpes zoster infection
- dysesthetic pain; tx is difficult
- trial of amitriptyline, carbamazepine, capsaicin, gabapentin
- the pain usually subsides in most cases
34
other infectious causes of neuropathies? (4)
- leprosy
- diphtheria
- lyme disease
- HIV
35
other causes of peripheral neuropathies? (4)
- sarcoidosis: cranial mononeuropathies, peripheral neuropathy
- amyloidosis: ligh chains and transthyretin accumulation; small fiber neuropathy; ex: carpal tunnel syndrome
- nutritional: B1, B3, B6 (too little or too much), B12, Vitamin E
- paraneoplastic
36
what are the hereditary neuropathies? (2)
1. charcot-marie-tooth disease
| 2. porphyria
37
charcot-marie-tooth disease
- aka peroneal muscular atrophy
- autosomal dominant or recessive, X-linked
- type I = demyelinating type --> stork leg deformity, foot drop, steppage gait, palpabl enlarged nn., peripheral polyneuropathy
- type II = axonal type --> less severe, atrophy, peripheral polyneuriopathy
38
porphyria
- abnormal heme metabolism
- acute motor neuropathy w/ autonomic findings
- precipitated by barbiturates or other drugs
- associated w/ recurrent seizure episodes, psychiatric disturbances, abdominal pain
39
Bell's palsy = idiopathic facial mononeuropathy
- could be viral (HSV reactivation) or autoimmune (intranasal influenza vaccine)
- clinically 3 most important = facial paralysis, hyperacusis, impaired taste; can also see acute onset and preceded by pain behind the ear
40
ddx for u/l Bell's palsy
- diabetes mellitus
- trauma
- tumor
- CVA
- Guillain-Barre
- lyme disease
- ramsay hunt syndrome (VSV reactivation)
41
ddx for b/l Bell's palsy
- Guillain-Barre
- myasthenia gravis
- basal meningitis
- sarcoidosis
- lyme disease
42
ddx for recurrent Bell's palsy
- multiple sclerosis
- lyme disease
- sarcoidosis
43
workup for dx of Bell's palsy
- H&P
- CBC, UA, fasting glucose, sed rate
- chest x-ray, spinal tap, MRI
- EMG w/ NCS
44
tx of Bell's palsy
- protect the eye: lubrication and patching (preferably w/ cup patch)
- steroids: 1mg/kg prednisone daily x7-14d
- possibly antiviral agents depending on determined causation
- PT
- surgery in severe cases = if the lesion is 90% or more after 1wk of tx w/ meds
45
possible complication of Bell's palsy
- aberrant regeneration
| - hemifacial spasm = a short circuit in the n. causing the face to cramp up
46
prognosis for Bell's palsy
- poor prognosis factors = older age, HTN, impaired taste, pain other than in ear, complete facial weakness
- 84% achieve near normal function
47
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Trigeminal Neuralgia (Tic Douloureux)
general info
```
- onset in middle age and later life
- paroxysms of intense stabbing, shooting pain in V2 or V3 distribution
- recurrent pain; may last several weeks at a time
- triggered by shaving, brushing teeth, mouth movements, cold stimulus
- mistaken for sinus disease or tooth abscess
- basically a short circuit in the n. causing shock to pain fibers in face
48
Trigeminal Neuralgia: pathogenesis, causes, dx
- pathogenesis: unknown; ephaptic transmission; could be blood vessel next to the n. that pulsates and strips the n. over time causing the short circuit
- possible causes: idiopathic, MS, vascular, tumor
- to dx: get H&P and MRI
49
trigeminal neuralgia tx
- meds: typically use seizure meds b/c they stabilize membranes = phenytoin, carbamazepine, clonazepam, baclofen, lamotrigine
- can do surgery = Jannetta procedure: go into back of brain where CNV is and put a pad in to prevent the pulsation b/w blood vessel and n.
- can also do a Gasserian ganglion block = go in and kill the ganglion; the face will be left numb but there will be no more pain
50
Horner's syndrome: what it is, features, possible locations of lesion
- caused by interruption of sympathetic innervation anywhere along its course
- features = miosis, anhydrosis, ptosis; also heterochromia iridis = different colored eyes --> pigmentation is from neural crest cells so if no autonomics are going to the iris the neural crest cells can't get there either = no pigmentation = one pale blue eye
- location: central = first order; preganglionic = second order; postganglionic = 3rd order
51
possible causes of Horner's and dx
- CVA
- cervical spine disease
- T1 radiculopathy - Paincoast's tumor
- neck pathology - thyroiditis
- carotid a. dissection
- cavernous sinus pathology - aneurysm
- orbital pathology
- to dx: H&P, cocaine test (blocks reuptake of norepi), hydroxyamphetamine test (stimulates release of norepi)
52
brachial plexopathies (5)
- klumpke palsy
- erb palsy
- idiopathic brachial plexitis
- shoulder dislocation
- cardiothoracic surgery
53
Klumpke and Erb palsies
- Erb much more common than Klumpke (98% v. 2%)
- possible causes of either: immunizations, infection, diabetes, vasculitis, trauma, surgery, heroin, radiation, idiopathic
54
idiopathic brachial plexitis
- aka Parsonage Turner syndrome = severe pain followed by weakness
- usually involves axillary, long thoracic, suprascapular nn; upper trunk
- sensory symptoms involve axillary distribution
- tx = PT, pain meds
- prognosis: 89% improve in 3 yrs; 5% recur
55
shoulder dislocation
- involves axillary and musculocutaneous nn., cords, or trunks
- more common anteriorly
- if a posterior dislocation you need to think about possible seizures
56
cardiothoracic surgery
- injury would involve the lower trunk or the medial cord of the brachial plexus
57
carpal tunnel syndrome: S&S
- paresthesias and dysesthesias in the hands, esp. first 3 digits
- pain worse at night and pts shakes their hands to take away pain
- atrophy of the thenar eminence
- + Tinel and Phalen signs
58
carpal tunnel: possible causes
- trauma - amyloid
- acromegaly - hypothyroidism
- pregnancy - structural changes
- rheumatoid arthritis - diabetes mellitus
59
carpal tunnel: dx and tx
- dx w/ H&P and EMG w/ NCS
| - tx w/ OMT, pyridoxine, job modification, splinting (cock up splints), steroids, surgery
60
ddx for carpal tunnel
- C6/7 radiculopathies = sensory symptoms
- C8/T1 radiculopathies = motor symptoms
- other median mononeuropathies
- thalamic infarct
61
ulnar mononeuropathy: S&S and causes
- numbness of medial 4th and entire 5th digit
- atrophy of hand (spares thenar eminence)
- entrapment sites = elbow and wrist
- + Tinel sign
- loss of dexterity, clawhand deformity
- causes = trauma (fx, compression), bony abnormalities (arthritis), diabetes mellitus
62
ulnar mononeuropathy: dx and tx
- dx w/ H&P and EMG w/ NCS
| - tx = correct underlying problem; job and habit modification; surgery if severe and no improvement w/ other methods
63
ddx for ulnar mononeuropathy
- C8/T1 radiculopathies
- plexopathy
- motor neuron disease
- syringomyelia
64
radial mononeuropathy: S&S and causes
- wrist drop
- finger drop
- numbness of posterior lateral hand
- causes = trauma (Saturday night palsy, crutches), injection, fx, lead, DM, handcuff neuropathy
65
radial mononeuropathy: dx and tx
- dx w/ H&P and EMG w/ NCS
| - tx = tx the underlying cause
66
ddx for radial mononeuropathy
- C7 radiculopathy
- plexopathy
- CVA --> to distinguish b/w CVA and radial n. injury evaluate the grip strength; strong grip + wrist drop = radial n. injury; weak grip + wrist drop = CVA
67
foot drop: what it is and possible injury sites
- b/c of weakness of tibialis anterior m.
- caused by anything that interrups innervation to the m.
- most common sites of injury = L4/5 roots and common fibular n.
- can also injure at fibular head, sciatic n. (anything involving sacral plexus), deep fibular n.
- women can damage n. by crossing legs all the time
68
fibular mononeuropathy: S&S and causes
- aka peroneal mononeuropathy
- foot drop
- numbness b/w 1st and 2nd toes and anterolateral leg
- tibialis posterior is unaffected
- causes = DM, trauma, compression, vasculitis
69
fibular mononeuropathy: dx and tx
- dx = H&P and EMG w/ NCS
| - tx = tx the underlying cause, could use AFO, PT PRN
70
sciatic mononeuropathy: anatomy (lateral v. medial trunk) and S&S
- lateral trunk = fibular n.
- medial trunk = tibial n.
- usually more fibular n. findings v. tibial n. findings
- S&S = weakness of all mm. below the knee, weak hamstrings, numbness below knee (except saphenous n. b/c it's a branch of the femoral n.), foot drop
71
sciatic mononeuropathy: causes, dx and tx
- causes = trauma, surgery, injection, external compression, masses
- dx and tx: same as fibular mononeuropathy = dx via H&P and EMG w/ NCs and tx the underlying cause, use AFO bracing and PT PRN
72
femoral mononeuropathy
- weakness of quad mm. = difficulty extending the knee
- numbness of medial leg
- causes = DM, catheterization, hematoma
- tx = underlying cause, straight leg bracing (something to keep knee extended), PT
73
Meralgia Paresthetica
- due to compression of lateral femoral cutaneous n.
- S&S = paresthesia or dysesthesia of lateral thigh
- causes = obesity, weight loss, tight clothes/belts
- tx = symptomatic; injection; transection of the n. (a bit extreme)
- very common condition; n. is a branch off the lumbar plexus
74
lumbosacral plexopathy: S&S and causes
- symptoms go beyond a single n. or root:
1. lumbar = iliopsoas, adductors, quads
2. sacral = gluteal, hamstrings, lower leg mm.
- causes = tumor, abscess, trauma, obstetric, hematoma, radiation, DM, idiopathic
75
lumbosacral plexopathy: dx and tx
- dx = H&P, EMG w/ NCS, imaging
| - tx = underlying cause, AFO, rehab
