What is the diagnosis and treatment approach for descending paralysis?

Diagnosis and Treatment Approach for Descending Paralysis

Descending paralysis is most commonly caused by botulism and requires immediate administration of botulinum antitoxin, ideally within 24 hours of symptom onset, to prevent progression of paralysis. 1

Differential Diagnosis

Botulism

• Characterized by descending flaccid paralysis starting with cranial nerves
• Key symptoms include:
  • Bulbar dysfunction (dysphagia, dysarthria, nasal voice, drooling)
  • Impaired gag reflex
  • Descending weakness pattern
  • Normal mental status despite facial paralysis
  • Normal cerebrospinal fluid findings 2, 1, 3

Guillain-Barré Syndrome (GBS)

• Typically presents as ascending paralysis but can rarely present as descending paralysis
• Characterized by:
  • Rapidly progressive, symmetric weakness
  • Absent or depressed tendon reflexes
  • Sensory signs
  • Elevated protein with normal cell count in CSF ("albuminocytologic dissociation") 2, 4, 5

Diagnostic Approach

1. Clinical Assessment:

   • Determine pattern of weakness (descending vs. ascending)
   • Evaluate cranial nerve function
   • Check deep tendon reflexes
   • Assess respiratory function
   • Look for autonomic dysfunction 2, 1

2. Laboratory Testing:

   • Lumbar puncture (normal in botulism, albuminocytologic dissociation in GBS)
   • Avoid routine laboratory testing in Bell's palsy 2

3. Electrophysiological Studies:

   • Helpful to distinguish between:
     • Botulism: neuromuscular junction disorder
     • GBS subtypes: AIDP, AMAN, AMSAN 2, 3

Treatment Approach

For Botulism:

1. Immediate Administration of Botulinum Antitoxin (BAT):

   • Standard adult dose: one vial intravenously
   • Should be given within 24 hours of symptom onset
   • Contact health department immediately for emergency consultation and antitoxin procurement 1

2. Supportive Care:

   • Continuous monitoring of respiratory function
   • Consider intubation if respiratory compromise (avoid succinylcholine, use rocuronium at 0.6 mg/kg if needed)
   • Cardiac monitoring and frequent blood pressure measurements
   • Monitor for complications:
     • Ventilator-associated pneumonia
     • Deep vein thrombosis
     • Pressure ulcers
     • Catheter-associated urinary tract infections 2, 1

For Guillain-Barré Syndrome:

1. Immunotherapy (initiate within 2 weeks of symptom onset):

   • Intravenous immunoglobulin (IVIG): 0.4 g/kg/day for 5 days, OR
   • Plasma exchange: 5 exchanges over 2 weeks 2, 1, 5

2. Supportive Care:

   • Respiratory monitoring (about 20% require mechanical ventilation)
   • Prevention of complications (DVT, pressure ulcers)
   • Cardiac monitoring for autonomic dysfunction
   • Pain management 2, 6

Prognosis

Botulism:

• With modern intensive care, mortality has decreased to <5%
• Recovery requires prolonged hospitalization (weeks to months)
• Monitor for delayed muscle weakness (can occur up to 4 days after exposure) 1

Guillain-Barré Syndrome:

• Severe persistent disability in 14% of patients at 1 year
• Loss of full strength, persistent pain, and need for professional change in about 40%
• Mortality is about 4% within the first year
• Poor prognostic factors include:
  • Higher age
  • Preceding diarrhea
  • Greater disability at admission
  • Short interval between symptom onset and admission
  • Need for mechanical ventilation
  • Absent/low amplitude compound muscle action potentials 6

Follow-up

• Regular reassessment of neurological function
• For GBS patients, monitor for treatment-related fluctuations versus acute-onset chronic inflammatory demyelinating polyneuropathy
• Psychosocial support for patients with persistent symptoms 2, 6