peripheral neuropathy Flashcards
peripheral relay info to and from the
CNS
peripheral nerves include
sensory and motor (ANS)
symptoms of peripheral neuropathy
numbess/tingling/prickling (paresthesis)
pain (allodynia)
may affect internal organs (ANS)
may lead to paralysis, muscle wasting, organ failure
mononeuroapthy
damage to one peripheral nerve (median in CTS)
polyneuropathy
multiple peripheral nerves throughout body
examples of polyneuropathy
guilian-barre syndrome, diabetes neuropathy, charcot-marie tooth disease
what parts of nerve may be damaged
axonal or myelin sheeth damage
what types of nerves may be damaged
motor
sensory
autonomic
these neuropathies are caused by?
physical injury/trauma
(repetitive stress, cumulative damage from repetitive use/compression injury or entrapment)
disease or disorders
(metabolic/endocrine or autoimmune…..)
ulnar nerve compression due to repetitive activity overuse is found in what canal
Guyon’s canal
what medications cause peripheral neuropathy?
AIDS antiviral drug didanosine
antibiotics
gold compounds
chemotherapy drugs
carpal tunnel syndrome due to
compression of median enrve cause of swelling in tissue in carpal tunnel
sensations of median nerve compression/entrapment (which fingers)
tingling/numbness of thumb, index, and middle fingers
median nerve is formed by what roots of BP
C5-C7 lateral cord of BP
C8-T1 median cord of BP
median nerve innervation
2LOAF
1st and 2nd lumbrical
opponens pollicis
abductor pollicis BREVIS
flexor pollicis BREVIS
conditions that may lead to carpal tunnel
obesity pregnancy diabetes arthritis hypothyrodism trauma repetitive work or task (cummulative trauma)
transverse carpel ligament release is for
carpal tunnel (median nerve)
CTS diagnosis
- examine neck, shoulder, elbow, pulses, and reflexes
- To exclude other conditions that can mimic carpal tunnel syndrome
- To identify compression
Wrist physical exam
◦ For swelling, warmth, tenderness, deformity, and discoloration
Phalen’s test & Tinel’s sign
Nerve Conduction Velocity & Electromyography
CTS symptoms
numbness “pins and needles in fingers”
pain that is worse at night (interupts sleep)
burning or tingling of thumb, index, and middle fingers or pain that moves up arm and elbow
hand weakness, difficulty gripping objects with hands, or dropping objects
difficulty manipualting small objects
swollen feeling in fingers
cubital tunnel syndrome has what symptoms
numbness and tingling along ulnar nerve
what is weak in cubital tunnel syndrome
weak grip
most common site of ulnar nerve compression
elbow (cubital tunnel syndrome)
ulnar innervation
forearm
flexor carpi ulnaris
flexor digi profundus (ulnar part)
thenar
adductor pollicis
flexor pollicis brevis (deep head)
fingers
palmar and dorsal interossei
3rd and 4th lumbricals
hypothenar muscles
abductor digi minimi
opponens digiti minimi
flexor digiti minimi
most common compressive neuropathy
carpal tunnel syndrome
2nd most common compressive neuropathy
cubitial tunnel syndrome
cubital tunnel syndrome affects what gender more
men
cubital tunnel may causes what deformity
ulnar claw hand deformity
cubital tunnel syndrome may be casued by
- constricting fascial bands ◦ subluxation of the ulnar nerve over the medial epicondyle ◦ cubitus valgus ◦ hypertrophied synovium ◦ tumors, ganglia ◦ direct compression ◦ repeated resting elbow on hard surface
Work may aggravate cubital tunnel syndrome secondary
to repetitive elbow flexion and extension
occupational implications for neuropathies
upper/lower extremity + hands
peripheral nerve injuries result in loss to what part of peripheral nerve
sensory, motor, or both
peripheral nerve injuries occur from
trauma (blunt or wound) or acute compression
peripheral nerve injuries may result
demyelination or axonal degeneration
neuropraxia is what level of severity?
lease severe nerve injury
neuropraxia
what is blocked?
no what?
most common finding?
◦ block of nerve conduction (temp), but axon and myeline sheet are intact
◦ demyelination of injured nerve
◦ no nerve denervation muscle changes
◦ no Tinel sign (test to detect/confirm injured or irritated nerve)
◦ recovery may be spontaneous or could take up to 12 weeks, recovery is usually complete
loss of motor function most common finding
axonotmesis
◦ common causes: traction (stretch injury causes BP injury) or crash injury
◦ anatomic disruption of axon with little disruption of connective tissue (n. sheath)
◦ requires regrowth of the axon to the target muscle
◦ prolonged recovery - axons grow in adults at about 1” per month (1mm per day)
◦ dennervated muscle will lose its nerve receptors within 12 to 18 months
neurotmesis
- anatomic disruption of both axon and connective tissue (sheath) – most severe type of nerve injury – less likely to recover by axonal regeneration – no chance of spontaneous recovery – early surgical treatment necessary
regeneration has to do with
peripheral nerve axons
reinnervation occurs only if
◦ sensory fibers reach their sensory end organs
◦ motor fibers reach their muscle targets
examples of reinnervation problems
Mismatched sensory fibers may reinnervate a different sensory area within the nerve’s sensory distribution
Motor fibers may regenerate but the muscle may not be completely reinnervated due to the long period of denervation
when do you indicate surgery for closed injuries
Surgery indicated if no evidence of recovery at 3 months following injury
majority of brachial plexus injuries caused by
trauma
brachial plexus injuries caused by
- motorcycle accidents ◦ Blunt trauma ◦ Stab or gunshot wounds ◦ Inflammatory (brachial plexitis) ◦ Compression (tumor) ◦ Neuropathies ◦ Obstetric brachial plexus palsy
BP avulsion injury
nerve has been pulled out from the spinal cord and has no chance to recover
BP rupture injury
nerve has been stretched and some torn, but not at the spinal cord
BP neurapraxia injury
nerve has been stretched or compressed but is still attached (not torn) and has excellent prognosis for rapid recovery (transient)
axonotmesis
axons have been severed; prognosis moderate
neurotmesis
entire nerve has been divided; prognosis very poor
crash injury (BP) surgery indications
◦ Surgical exploration of the nerve may be
delayed for as long as several weeks
◦ after 3 months with no evidence of reinnervation (electrodiagnostically or clinically), surgical repair or nerve graft indicated
how is BP nerve repaired?
Direct repair of nerve continuity
Performed when the 2 ends of the nerve are
directly coapted
Without tension
nerve graft
Recommended where a gap is present between the proximal and distal ends
Donor nerve harvest results in a sensory loss in the donor distribution
