side by side comparison

Myasthenia Gravis vs Guillain-Barré Syndrome: Descending vs Ascending Weakness

Both diseases cause progressive weakness that can paralyze the diaphragm, but one starts at the eyes and works down while the other starts at the feet and climbs up. Picking the wrong direction on NCLEX means you'll miss the respiratory decline trajectory and choose the wrong intervention.

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Comparison

Side-by-side2 compared
Dimension
Myasthenia Gravis
Guillain-Barré
Pathophysiology & onset
  • Autoimmune anti-AChR antibodies at NMJ
  • Chronic, relapsing-remitting onset
  • Post-infectious demyelination (Campylobacter)
  • Acute
  • peaks at 2–4 weeks
Signs & symptoms
  • DESCENDING: ptosis/diplopia then bulbar then limbs
  • ★Worsens with use, improves with rest
  • ★ASCENDING: feet/legs then trunk then arms
  • Constant weakness
  • no rest improvement
Diagnostics
  • Edrophonium (Tensilon) test confirms MG
  • Anti-AChR antibodies present
  • ★CSF: ↑ protein, normal WBC
  • Areflexia — absent reflexes
Respiratory priorities
  • Monitor serial NIF & vital capacity
  • Myasthenic crisis: sudden vent failure
  • Monitor serial NIF & vital capacity
  • Intubate if VC < 15 mL/kg
Treatment
  • Pyridostigmine
  • thymectomy
  • Plasmapheresis or IVIG
  • Plasmapheresis or IVIG
  • ★NO anticholinesterases
Patient teaching
  • Take pyridostigmine on time, before meals
  • Pace activity
  • rest between tasks
  • Recovery is gradual over weeks–months
  • PT/OT, DVT prevention during paralysis
Crisis — escalate
  • Myasthenic crisis: undermedication
  • Cholinergic crisis: overmed (SLUDGE)
  • Respiratory failure from ascending paralysis
  • Autonomic instability: BP/HR swings
Prognosis
  • Chronic — managed not cured
  • normal lifespan
  • 80% regain full function over wk–mo
Pathophysiology & onset

Myasthenia Gravis

  • Autoimmune anti-AChR antibodies at NMJ
  • Chronic, relapsing-remitting onset

Guillain-Barré

  • Post-infectious demyelination (Campylobacter)
  • Acute
  • peaks at 2–4 weeks
Signs & symptoms

Myasthenia Gravis

  • DESCENDING: ptosis/diplopia then bulbar then limbs
  • ★Worsens with use, improves with rest

Guillain-Barré

  • ★ASCENDING: feet/legs then trunk then arms
  • Constant weakness
  • no rest improvement
Diagnostics

Myasthenia Gravis

  • Edrophonium (Tensilon) test confirms MG
  • Anti-AChR antibodies present

Guillain-Barré

  • ★CSF: ↑ protein, normal WBC
  • Areflexia — absent reflexes
Respiratory priorities

Myasthenia Gravis

  • Monitor serial NIF & vital capacity
  • Myasthenic crisis: sudden vent failure

Guillain-Barré

  • Monitor serial NIF & vital capacity
  • Intubate if VC < 15 mL/kg
Treatment

Myasthenia Gravis

  • Pyridostigmine
  • thymectomy
  • Plasmapheresis or IVIG

Guillain-Barré

  • Plasmapheresis or IVIG
  • ★NO anticholinesterases
Patient teaching

Myasthenia Gravis

  • Take pyridostigmine on time, before meals
  • Pace activity
  • rest between tasks

Guillain-Barré

  • Recovery is gradual over weeks–months
  • PT/OT, DVT prevention during paralysis
Crisis — escalate

Myasthenia Gravis

  • Myasthenic crisis: undermedication
  • Cholinergic crisis: overmed (SLUDGE)

Guillain-Barré

  • Respiratory failure from ascending paralysis
  • Autonomic instability: BP/HR swings
Prognosis

Myasthenia Gravis

  • Chronic — managed not cured
  • normal lifespan

Guillain-Barré

  • 80% regain full function over wk–mo

★ marks the fact that sets a column apart.

Clinical Pearl

MG drops Down from the eyes; GBS Gets up from the Ground — both can stop breathing.

Component Topics

Guillain-Barre SyndromeMyasthenia Gravis

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