Spinal Nerves and Plexes (4B) EXAM 2 Material Flashcards
Dysfunction of Peripheral Nerves: Sensory Changes
Decreased, lost and/or abnormal sensations
Parasthesia
Painless abnormal sensation in the absence of nocioceptor (pain receptor) stimulation.
Dysesthesia
Unpleasant abnormal sensation, evoked or spontanious.
Types of Dyesthesia
Allodynia
Hyperalgesoa
Allodynia
A type of dyesthesia
Pain from stimulus that normally wouldn’t cause pain. (ex: Sunburnt and putting shirt on).
Hyperalgesia
A type of dyesthesia
Excessive sensitivity to typically mild painful stimuli. (ex: Trigeminal Neuralgia)
Dysfunction of Peripheral Nerves: Motor Changes
Paresis / Paralysis, muscle atrophy progresses rapidly.
Dysfunction of Peripheral Nerves: Autonomic Changes
Difficulty regulating basic body functions.
If one nerve is damaged in the PNS (Autonomic Changes) what is the result:
Changes only seen if the nerve is completely severed…lack of sweating would occur.
If many nerves are damaged in the PNS (Autonomic Changes) What is the result:
Difficulty regulating blood pressure, heart rate, sweating
Dysfunction of Peripheral Nerves: Trophic Changes
(Trophic means skin)
- Skin becomes shiny; nails brittle; subcutaneous tissue thickens
- Ulceration of tissues
- Poor healing of wounds and infections.
Skin becoming shiny; brittle nails; subcutaneous tissue thickening is a sign of what kind of peripheral nerve dysfunction?
Trophic Change
Disease of dysfunction of one of more peripheral nerves
Neuropathy
Single peripheral nerve disease or dysfunction
Mononeuropathy
Which type of neuropathy has focal dysfunction?
Mononeuropathy
Which type of neuropathy damage can be to the axon, myelin sheath or both?
Mononeuropathy
Which type of neuropathy usually results from trauma?
Mononeuropathy
Neuropathies: Several individual nerves; multifocal dysfunction that presents as asymmetircal involvement of individual nerves:
Multiple mononeuropathies
Mononeuropathy: Class I - Neuropraxia
Impingement or compression of nerve –> loss of myelin limited to the site of injury, NO damage to axon
ex: Carpal tunnel syndrome
What is the prognosis of neuropraxia? (Mononeuropathy Class I)
Recovery tends to be complete
Mononeuropathy: Class II - Axontmesis
Axon is cut with myelin and connective tissues in tact
Ex: A hard crush of the nerve, due to dislocation or closed fractures
What is the prognosis of axontmesis? (Mononeuropathy
Class II)
Recovery is generally good
Mononeuropathy: Class III - Neurotmesis
Entire nerve is cut - both axons and membranes
ex: Excessive stretch
What is a result of neurotmesis?
Loss of sensation and muscle paralysis in area supported by the nerve affected.
What is the prognosis of neurotmesis (Mononeuropathy Class III)
Recovery is similar to axontmesis but the nerve conduction distal to the injury may never return due to poor regeneration.
Class Levels of Mononeuropathy:
And regeneration potential
Class I: Neuropraxia (Good)
Class II: Axontmesis (Good)
Class III: Neurotmesis (Variable)
Polyneuropathy
Damage to many nerves
Etiology of Polyneuropathy:
Toxic, Metabolic or autoimmune
Example of a Polyneuropathy:
Guillian Barre (demyelination of PNS nerves)
How does polyneuropathy typical present itself?
Distally and symmetrically
Hallmark is symmetrical involvement of sensory, motor and autonomic fibers, often progressing from distal to proximal
Polyneuropathy typically progresses from proximal to distal, or distal to proximal?
Distal to proximal
Where do symptoms often begin in polyneuropathy?
Feet, then appear in hands
Trophic changes of Polyneuropathy:
Poor healing, ulceration of skin, neurogenic joint damage, lack of sensation
Diabetic Polyneuropathy:
Axons and myelin are damaged
Usually WHAT is most affected in Diabetic Polyneuropathy?
Sensation
“Glove/Stocking” distribution
Proper diabetic foot care is important in what neuropathic disorder?
Diabetic Polyneuropathy
Motor problems in Diabetic Polyneuropathy:
Balance and coordination issues, weakness
What autonomic functions are susceptible to diabetic polyneuropathy?
Usually all autonomic functions are susceptible.
Cardiovascular, Gastrointestinal, Genitourinary and sweating dysfunction are common.
Retrograde Degeneration
Degeneration of proximal axon
Degeneration of distal axon
Orthograde (Wallerian)
Is axonal growth and regeneration in PNS possible?
yes, proximal stumps begin to sprout
Is regeneration slow or fast?
Slow (1-2 mm/day)
Rule of thumb with PNS regeneration
The more distal the lesion, the better the prognosis
