Flashcards in Peripheral Neuropathies Deck (62)
Examples of pain/temp small fiber pathologies
Examples of proprioception/vibration fiber pathologies
Vit B12 deficiency
Examples of motor fiber pathologies
Acute intermittent porphyria
Examples of autonomic fiber pathologies
Sx and PE of pain/temp fiber damage
pain, burning, shock-like, stabbing, dysesthesias, allodynia, paresthesias
PE: decreased response to painful stimuli (pin prick), decreased temp sensation (light touch)
Sx and PE of proprioception/vibration fiber damage
numbness, pins & needles, poor balance
PE: decreased proprioception and vibration (joint position sense); diminished DTRs
Sx and PE of motor fiber damage
cramps, weak grip, foot drop, fasciculations
PE: weakness, diminished DTRs
Autonomic nerve damage sx and PE
lightheaded, dry eyes/mouth, abnormal sweating, erectile dysfxn
PE: orthostasis, anisocoria (unequal pupils)
Location of peripheral neuropathies
outside brain and spinal cord
Which cranial nerves are involved in peripheral neuropathy?
all cranial nerves except I and II
Most common causes in U.S.? worldwide?
US: DM and alcohol
Most common presentation of peripheral neuropathy?
distal symmetric sensorimotor dysfxn
How are PN categorized by pattern of involvement?
- mononeuropathy = single nerve and its innervation
- Multiple mononeuropathy = multiple indiv peripheral nerves
- Polyneuropathy = widespread distribution
symmetric vs asymmetric, distal vs proximal
Likely cause of mononeuropathy
compression, trauma, vascular cause
common distribution of polyneuropathies
How are PN categorized by time course?
acute: toxic or inflamm
subacute: chemo, lead
chronic: DM, Charcott-Marie-Tooth
recurrent: Guillan-Barre, HIV
How are PN categorized?
Axonal or Demyelinating
Common example of demyelinating disease
neuropathy with axonal and myelin sheath degeneration DISTAL to injury (Wallerian degeneration)
median neuritis, radial neuritis, ulnar neuritis, peroneal neuritis
Hypothesis for why so many diabetics get neuropathy?
direct axonal loss and demyelination secondary to hyperglycemia OR insufficient blood flow in vaso nervorium
Most common diabetic neuropathy
diabetic sensorimotor polyneuropathy (DSPN)
Complications of diabetic neuropathy
foot ulcers, Charcot joint
Where nerve fibers affected in DSPN?
mixed with small and large fibers, sensory, motor, and autonomic
sensory and autonomic >> motor
symptoms of DSPN
initially distal: numbness/tingling, burning of toes/feet
progresses to proximal: up leg and to hands ("stocking-glove")
later: gait disturbances, distal motor weakness
PE of diabetic neuropathy
Distal sensory loss of pain, temp, touch, vibration
Reduced DTRs at ankle
What are signs of autonomic fiber involvement?
impotence, nocturnal diarrhea, difficulty voiding, abnormal sweating, orthostatic hypotension
Asymmetric Diabetic Neuropathy
- occurs in older puts who already have DSPN
- involves CN VI, III, and sometimes IV (abrupt onset d/t acute ischemia)
- radiculopathies, limb mononeuropathies
CN VI palsy affects on vision
painless double vision (diplopia)