Disorders of Peripheral Nervous System Flashcards
What is the most common cause of acute evolving motor & sensory deficits?
Guillain-Barré syndrome (GBS)
What age groups are affected by GBS?
- Young adults
- 50-80 y/o
T/F: females are more likely to get GBS
False- slightly more males develop GBS
What is the etiology of GBS and what often precedes GBS?
- Immune-mediated disorder
- Acute infection often precedes
What are some common triggers for GBS?
- Viral (Haemophilus influenza, Epstein-Barr, Cytomegalovirus)
- Bacterial (Campylobacter jejuni)
- Surgery
- Vaccines
What is the pathogenesis of GBS in regards to demyelination of PNS?
- Antibodies bind to myelin of Schwann cells
- Macrophages respond to inflammatory signals & strip myelin from nerves
In regards to pathogenesis of GBS how does remyelination occur?
Schwann cells divide & remyelinate nerve axons
Why may there be axonal damage in an individual with GBS?
Inflammation
What axons are affected by GBS?
- Motor
- Motor and sensory
What is the clinical presentation of Acute Inflammatory demyelinating polyneuropathy (AIDP)?
A variant of GBS
progressive paralysis & areflexia due to demyelination
What is the clinical presentation of acute motor axonal neuropathy (AMAN)?
A variant of GBS
Axon involved, more severe, more respiratory involvement, more significant residual impairments
What is the clinical presentation of acute motor & sensory axonal neuropathy (AMSAN)?
A variant of GBS
Same as AMAN but with sensory involvement
What is the clinical presentation of Acute sensory ascending neuropathy (ASAN)?
A variant of GBS
Sensory > Motor
What is the clinical presentation of Miller Fisher syndrome?
A variant of GBS
Opthalmoplegia, ataxia, areflexia with sparing of strength
What is the clinical presentation of chronic inflammatory demyelinating polyneuropathy?
A variant of GBS
Slower onset, relapses & remissions or slow progression
What are the clinical manifestations of GBS?
- Variation b/w subtypes
- Ascending symmetrical weakness & distal sensory impairments
- Flaccid paralysis
- Absence of DTRs
- Time from onset to peak impairment < 4 weeks
- 30% require mechanical ventilation
What are the GBS stages and what occurs in each?
- Progressive impairment (distal to proximal)
- Static phase (2-4 wks)
- Recovery (proximal to distal, may take months or years)
What symptoms are required for diagnosis of GBS?
- Progressive weakness in > 1 extremity
- Loss of DTRs
What symptoms are supportive of a diagnosis of GBS?
- Weakness developing rapidly ceasing to progress by week 4
- Symmetric weakness
- Mild sensory signs & symptoms
- Facial weakness
- Recovery starts 2-4 wks after progression ceases
- Tachycardia, cardiac arrhythmias, & labile BP possbile
- Absence of fever
In order to diagnose GBS what features must the CSF have?
- CSF protein levels increase after 1 week (continue to increase with serial exams)
- CSF contains < 10 mononuclear leukocytes/mm3
In order to diagnosis GBS what must the electrodiagnostic test show?
Nerve conduction velocity slowed
What are some interventions for GBS?
- Control of autoimmune responses
- Mechanical ventilation
- Prevention of effects of immobility
What is the prognosis of GBS in regards to:
- Mortality rate?
- Recurrent form?
- 1 year?
- Mortality rate: 5%
- Recurrent form: 10%
- 1 year: 67% complete recovery, 20% significant disability)
What are the indications of a poor prognosis of GBS?
- Older
- Increase time before recovery begins
- Need for artificial respiration
- Reduced evoked potential (sign of axonal damage)
