Neuropathies Flashcards
What disease populations are at high risk for developing neuropathies?
HIV
Diabetic
Hep C
autoimmune
cancer
leprosy
What is one important physical finding that distinguishes peripheral neuropathy from radiculopathy?
in PN, many or all of the dermatomes are affected as opposed to radiculopathy, which is usually isolated to a single dermatome
Neuropathy patients are typically weakest where and why?
In the most distal locations (feet first) because longest nerve tracts degenerate first
What is the typical pattern of a peripheral sensory neuropathy?
stocking/glove pattern, but don’t forget center thorax and abdomen
What two sensory modalities are part of the physical exam and test the spinothalamic tract?
pinprick (pain)
temperature
What two sensory modalities are part of the physical exam and test the corticospinal tract?
vibration
proprioception
Which type of fibers are typically impaired in spintothalamic tract testing (pinprick and temperature)?
small fibers
What type of fibers are typically impaired in the corticospinal tract (vibration and sensation)
large fibers
What additional tests should be given to all patients with PSN?
- 2 hour oral glucose tolerance test/HgbA1C
- hepatitis serologies
- autoimmune diseases (ANA, RF, SS-A, SS-B)
- B12 deficiency
What other tests might one consider in a patient with PSN?
HIV
B6
multiple myeloma
What is the test of choice for large fiber neuropathies?
Nerve conduction velocity
What is a genetic cause of PSN?
Charcot-Marie-Tooth
*heterogenous - need to know mutation
What is the first line treatment in PSN?
anti-convulsants
What is the most commonly prescribed anticonvulsant for PSN?
Gabapentin
*good safety profile, takes a few weeks to titrate
What can be used to treat breaktrhough pain in PSN?
Tramadol or other weak mu-opiod agonists
*not acceptable as a daily medication
Are opiates considered therapeutic for PSN?
Not usually -typically not effective for neuropathic pain and there’s substantial risk of addiction/dependence
What treatment is particularly good for focal neuropathies?
Lidocaine patches/topical creams
What is the role of exercise in the treatment of PSN?
exercise may be helpful for peripheral nerve regeneration (not just symptoms)*
non-weight bearing exercise is good for people with PSN because it won’t exacerbate symptoms
*need more research
What are the important components of patient education for PSN?
- daily foot inspection
- podiatry/assistance for nail cutting
- fall prevention
- risks of chemo and fluroquinolones
- medication titration
Why would you chose an anticonvulsant over other therapies for PSN?
patient needs to be alert for work or driving
Why would you select antidepressants as a first choice for a patient with PSN?
patient is concurrently despressed?
What would be a good medication first choice for a patient with PSN and insomnia
tricyclic antidepressants at bedtime
What medications would you avoid in PSN in a patient with chronic constipation?
TCAs, Tramadol and Opiates
What medications would you avoid in PSN for an older /orthostatic patient?
TCAs
What are the common sites for compression neuropathies?
carpal tunnel
thoracic outlet
ulnar entrapment at the elbow (cubital tunnel)
tarsal tunnel
What is the most common compression neuropathy?
carpal tunnel syndrome (CTS)
What is the pathophysiology of CTS?
compromise of the median nerve at the wrist caused by increased perssure in the carpal tunnel (bounded by the carpal bones and transverse carpal ligament)
What are the risk factors for CTS?
- genetic pre-disposition
- diabetes
- pregnancy (esp. the swollen third trimester)
- obesity
- age
- repetitive strain and work
What are the symptoms of CTS?
- dull, aching discomfort in the hand, forearm, upper arm
- “pins and needles” or “electrical shocks”
- weakness or clumsiness of the hand
- provocation with sleep or repetitive motion
- improvement with change in position or shaking of wrist
Special testing to Dx CTS
+ Tinsel’s test - tapping on median nerve to see if it reproduces symtpoms
+Phelan’s test - place wrists in 90 degree flexion, facing each other for 1 minute to see if it reproduces symptoms
How do you Dx CTS?
abnormal nerve conduction tests
special testing
wasting/atrophy of the hand muscles (late sign)
Rx of CTS
carpal tunnel splints
NSAIDs
PT
steroid injections
surgical decompression of carpal tunnel
What neurological disease is progressive and attacks both upper and lower motor neurons resulting in muscle weakness and atrophy?
Amyothrophic Lateral Sclerosis (ALS)
What disease presents with signs and symptoms such as: weakness and muscles, weight loss, atrophy, stiffness, fasciculations, twitching and worsening fatigure?
ALS
NB: roughly 15% present with weakness in facial muscles, trouble speaking, swallowing, chewing or coughing as the first complaint. Worse prognosis
What symptoms do you NOT see in ALS?
pain
sensory symptoms or senory level
loss of bowel or bladder control
difficulties with extra-ocular movements
rapidly progressing symptoms
What are the important signs of ALS?
muscle weakness in facial/limb
atrophy
hyperreflexia
drooling
emotionally labile
How do you diagnose ALS?
mostly exam and physical, but you can do nerve conduction studies
How do you treat ALS?
Riluzole (Rilutek)
*shown to extend the time patient can breathe witout mechanical ventilation
symptomatic
psych/social work
Prognosis for ALS?
Median survival is three years after dx
death due to respiratory failure
What are the differences in an upper motor and lotor motor neuron lesion in the following categories:
- weakness
- atrophy
- fasciculations
- reflexes
- tone
Any time you see shingles in the V1 (ophthalmic division of CN V) including on the tip of the nose, what disease MUST you consider?
Herpes Ophthalmicus
*medical emergency, refer immediately to the ophthalmologist
What disorder has unilateral facial paralysis, including paralysis of the forehead muscles?
Bell’s Palsy - CNVII Palsy
What is the pathophysiology of Bell’s Palsy?
- it’s not well known, but a few hypotheses:
- compression of the facial nerve
- injury to the facial nerve
- autoimmune attack
What are the symptoms of Bell’s?
- facial muscle weakness over days-weeks
- change in taste, lacrimation
- hyperacusis
- facial tingling or pain near ear (subset)
Bell’s Treatment?
- if within the first 72 hours, acyclovir and steroids
- eye patch
- pain control
What is the prognosis for Bell’s palsy?
- worse with:
- increasing
- severe pain
- complete palsy
What is the epidemiology of Trigeminal Neuralgia?
Famales: males = 2:1
Age > 40 years
highest prevalence 70s
What are the symptoms of trigeminal neuralgia?
- recurrent episodes of severe pain on one side of the face in the CN V distribution
- will occur in response to even light touch or yawning, swallowing
What is the Rx for Trigeminal Neuralgia?
- anti-convulsant medications (works for 70%)
- glycerol injections
- gamma knife radiosurgery
- microvascular decompression surgery (most invasive)
Shingles epidemiology
- 10-20% of people
- more likely when immunocompromised or stressed
What are the symptoms of herpes zoster?
- prodrome 2-4 days before, tingling, itching or pain in dermatomal distribution
- rash ALWAYS consists of grouped vesicles on an erythematous base
- ALWAYS in a dermatomal distribution
- NEVER crossing the midline
Rx of Herpes Zoster
- anti-virals if in the first 72 hours of rash (acyclovir)
- pain control - opiates, anti-convulsants, tramadol
What is the clinical definition of post-herpetic neuralgia?
- persistent pain in area previously affected by herpes zoster for more than 3 months
- pain is severe - “electrical shock”
- deep, severe itching
- hypersensitive skin
What are the risks for developing post-herpetic neuralgia?
- advanced age (>50)
- female
- presence of prodromal symptoms
- severe pain at presentation of rash (>5)
what is the Rx for post-herpetic neuralgia?
- anti-convulstants (gabapentin common)
- anti-depressants (TCA and SNRI)
- weak mu-opiod agonsists (tramadol/zydol)
- opiates
- lidocaine patches/topical creams
