4. Disorders of the PNS Flashcards
- Disorder of cerebrum
- Disorder of spinal cord
- Disorder of the root
- Disorder of the plexus
- Disorder of many nerves
- Disorder of one nerve
- Disorder of muscle
- Encephalopathy
- Myelopathy
- Radiculopathy
- Plexopathy
- Polyneuropathy
- Mononeuropathy
- Myopathy
A process in which the nerve degenerates from the point of axonal damage outward; cell swelling, peripheral movement of nucleus, and chromatolysis (degradation of nissl substance)
Wallerian Degeneration
Focal degeneration of the Myelin Sheath with SPARING of axon; muscle atrophy does NOT occur
Segmental Demyelination
When the axon breaks down and “dies back”; often systemic and is progressive from distal to proximal; muscle atrophy DOES occur
Axonal Degeneration
A disorder of PNS; usually DISTAL and SYMMETRIC loss of tendon reflexes; both motor and sensory deficits; LOWER motor neuron findings; function and reflexes; include Arsenic poisoning, Guillian-Barre, Diabetic neuropathy, and CMT
Polyneuropathy
Overall, DISTAL motor problems are usually (nervous/muscular) in origin
Nervous
Examples of ACUTE Polyneuropathies (3 total)
Arsenic Poisoning
Porphyria
Guillian-Barre
Examples of CHRONIC Polyneuropathies (4 total)
Diabetic Neuropathy
B12 Deficiency
CIDP
Charcot-Marie Tooth Disease
ACUTE Polyneuropathy; LIFE-THREATENING immune-mediated demyelination of spinal nerve roots and PNS; DISTAL limb weakness, but rapidly ascending paralysis; loss of deep tendon reflexes; usually preceded by a “flu-like” illness or Campylobacter jejuni infection; Elevated CSF protein
Guillain-Barre Syndrome
Which Polyneuropathy is referred to as a “ascending” paralysis
Guillain-Barre Syndrome (aka. AIDP)
Causes of Guillain-Barre Syndrome
Preceding “flu-like” illness associated with Campylobacter jejuni infection
*causes immune-mediated damage to neurons
Guillain-Barre Syndrome is characterized by (ascending/descending) paralysis and associated with (Campylobacter/Clostridium)
Ascending; Campylobacter
CHRONIC Polyneuropathy; appearance of VERY THIN legs in proportion to proximal legs, pes cavus (high arches with hammer toes); histologic finding of onion bulb; patient are usually asymptomatic, but eventually complain of foot pain or dysfunction
Charcot-Marie Tooth Disease
Physical appearance of Charcot-Marie Tooth Disease
Thin lower legs (calf atrophy)
High arches
Hammer toes
CHRONIC Polyneuropathy; due to longstanding diabetes; report distal (feet before hands) SENSORY loss with a “burning” pain; high risk for amputations due to incidental damage; also results in autonomic dysfunction (orthostatic hypotension, dec. bladder emptying, etc.)
Diabetic Neuropathy
What is the common sensation patient with Diabetic Neuropathy complain of?
“Burning” pain
*usually distal
Autonomic dysfunction of diabetic neuropathy
- Orthostatic hypotension
- dec. bladder emptying
- post prandial nausea
A disorder caused by median nerve entrapment; C6 or C7 radiculopathy –> weak thumb abduction & opposition; thenar atrophy
Carpal Tunnel Syndrome
A disorder that occurs at elbow & wrist (Guyon’s Canal) –> weak finger/wrist flexion
Ulnar nerve palsy
A disorder that is most common at the spiral (radial) groove –> Saturday Night Palsy (weak finger/wrist extensors; wrist drop)
Radial nerve palsy
A disorder that is caused by compression just below the knee –> foot drop; steppage gait; weak foot dorsiflexion/eversion
Fibular (peroneal) nerve palsy
A disorder that is caused by compression and trauma –> weakness of leg and hamstrings; absent ankle jerk
Sciatic Nerve Palsy
A disorder caused by trauma/hematoma –> weak quads; numbness in anteriomedial thigh/shin; absent knee jerk; tight jeans can cause this (“meralgia paresthetica”)
Femoral Nerve Palsy
(Neuropathy/Myopathy)
Distal > Proximal Reduced reflexes \+ Sensory symptoms \+/- autonomic symptoms Normal serum CK
Neuropathy
