Neuropathy Inflammatory and Immune-Mediated Neuropathy 2 — Questions and Answers
Question 1: What is the most common identifiable infectious trigger for Guillain-Barré Syndrome?
- Influenza A virus
- Campylobacter jejuni (Correct answer)
- Staphylococcus aureus
- Epstein-Barr virus
Correct answer: Campylobacter jejuni
Campylobacter jejuni gastroenteritis is the most frequently identified precipitant of GBS, accounting for approximately 30% of cases through molecular mimicry.
Question 2: Which nerve conduction study pattern is most characteristic of CIDP?
- Normal conduction velocities with reduced amplitudes only
- Prolonged distal latencies, slowed conduction velocities, conduction block, and temporal dispersion (Correct answer)
- Absent F-waves as the only abnormality
- Fibrillation potentials on needle EMG only
Correct answer: Prolonged distal latencies, slowed conduction velocities, conduction block, and temporal dispersion
CIDP shows a diffuse demyelinating pattern on nerve conduction studies with prolonged distal latencies, markedly slowed conduction velocities, conduction block, and temporal dispersion.
Question 3: Which antibody is highly specific for Miller Fisher Syndrome, a variant of GBS?
- Anti-GM1 IgM
- Anti-GQ1b IgG (Correct answer)
- Anti-MAG IgM
- Anti-Hu IgG
Correct answer: Anti-GQ1b IgG
Anti-GQ1b IgG antibodies are present in over 90% of Miller Fisher Syndrome cases and are highly specific, targeting gangliosides concentrated at cranial nerve nodes of Ranvier.
Question 4: What is the primary mechanism by which IVIG benefits patients with inflammatory neuropathies?
- Direct regeneration of damaged myelin sheaths
- Immune modulation through Fc receptor blockade, complement inhibition, and idiotype interactions (Correct answer)
- Replacement of antibodies depleted by autoimmune attack
- Direct antibacterial action against triggering pathogens
Correct answer: Immune modulation through Fc receptor blockade, complement inhibition, and idiotype interactions
IVIG exerts multiple immunomodulatory effects including Fc receptor blockade on macrophages, complement activation inhibition, and neutralization of pathogenic antibodies.
Question 5: Which systemic connective tissue disease is most commonly associated with vasculitic neuropathy?
- Type 2 diabetes mellitus
- Rheumatoid arthritis (Correct answer)
- Essential hypertension
- Primary hypothyroidism
Correct answer: Rheumatoid arthritis
Rheumatoid arthritis is among the most common systemic causes of vasculitic neuropathy, along with other connective tissue diseases such as lupus and Sjögren's syndrome.
Question 6: How does plasmapheresis benefit patients with Guillain-Barré Syndrome?
- It stimulates peripheral nerve regeneration
- It removes pathogenic autoantibodies and complement from the circulation (Correct answer)
- It provides replacement immunoglobulins to boost immunity
- It blocks nerve conduction to reduce pain
Correct answer: It removes pathogenic autoantibodies and complement from the circulation
Plasmapheresis physically removes the harmful autoantibodies and complement factors from the plasma that are targeting and destroying the myelin of peripheral nerves in GBS.
Question 7: Which condition is a relative contraindication to plasmapheresis in GBS management?
- Patient age over 65 years
- Severe hemodynamic instability or active sepsis (Correct answer)
- Mild lower limb weakness only
- Elevated CSF protein level
Correct answer: Severe hemodynamic instability or active sepsis
Severe hemodynamic instability and active sepsis are contraindications to plasmapheresis because the large-volume fluid shifts and hypotension during the procedure pose life-threatening risks.
Neuropathy Inflammatory and Immune-Mediated Neuropathy 2
What is the most common identifiable infectious trigger for Guillain-Barré Syndrome?