Exam 2: PNS Flashcards
Myasthenia
Painless weakness
Pathology of any portion of motor unit may cause
Skeletal muscle dysfunction
Axon neuropathy involved direct injury to
Axon
Areas of injury for PNS damage
Lower motor neuron/ peripheral axon
NMJ
Innervated myoctyes
Myelin in PNS created by
Schwann cells
2 types of neuropathy
Axonal
Demyelinating
Wallerian degeneration
Distal to injury breaks down
Demyelinating neuropathy involves damage to
Myelin or Schwann cells
Peripheral neurons have ability to
Regrow
Remyelinate
With regrowth and demyelination of PNS…
Low axon density
Low amplitude on NCV
Demyelinating neuropathy spares
Axon
Segmental demyelination
Random demyelination
Repair of demyelinating neuropathy
Thin myelin
Short internodes
Mononeuropathy always involves either
Entrapment
Trauma
Polyneuropathy involves
Many nerves damaged from metabolic problems
Stocking and glove paresthesia observed in
Polyneuropathy
Rubbery legs, ascending paralysis, and respiratory failure observed in
GBS
Guillain-Barre Syndrome (GBS)
Acute motor neurons demyelination
Autoimmune
Age and sex MC in GBS
Males
15-35 or 50-60
Causes of PNS injury
Malnutrished Toxic Vascular Inflammatory Genetic
Most cases of GBS ___
Self-resolve
___ near motor nerve roots in GBS
Macrophages
Treatment for GBS
Ventilation
IV ABs
Chronic inflammatory demyelinating polyneuropathy (CIDP)
Chronic version of GBS
Sensorimotor abnormalities at least 2 months
Schwann cells resembling onion bulbs observed in
CIDP
Age and sex MC for CIDP
Males 2X
40-60 yo
Microangiopathy drives
Diabetes problems
In diabetes, ROS damages
Vasa nervorum
Nerve injury in diabetes begins with
Decrease sensation
Treatment for diabetic peripheral neuropathy
Glucose control
Daily inspection
Analgesics
Anticonvulsants
Diabetic peripheral neuropathy injures both
Myelin and axons
Microangiopathy in diabetes peripheral neuropathy damages PNS neurons especially in the
Retina
Kidney
Neuropathic arthropathy involves progressive degeneration of
Weight bearing joints
Foot, ankle, hip
TM and MP joints
Neuropathic arthropathy can be a complication of any neuropathy, particularly
DM
Spinal cord injury
Syphilis
Leprosy
Neuropathic arthropathy causes decrease sensation, cause
Unperceived trauma
Environmental exposure that damages peripheral nerves affects
Longest neurons
Mononeuritis multiplex
Neuronal damage from vasculitis
Charcot-Marie-Tooth disease
Inherited conditions of axonal or demyelinating neuropathy
CMT disease due to
PMP22 mutation
Variable severity is observed in CMT disease, common symptoms are
Pes cavus
Altered gait
Myasthenia gravis
Autoimmune attack on post-synaptic ACH receptors
Extraocular weakness, including ptosis and diplopia, seen in
Myasthenia gravis
60% cases myasthenia gravis due to ____ and 20% due to ____
Thymus hyperplasia
Thymoma
Age and sex for myasthenia gravis
Females MC : 20-30
Males: 50-70