Makindo Medical Notes

Related Subjects: |Herpes Varicella-Zoster (Shingles) Infection |Herpes Viruses |Herpes Zoster Ophthalmicus (HZO) Shingles |MonkeyPox |Mumps |Measles |Rubella (German Measles) |Epstein-Barr Virus infection |Cytomegalovirus (CMV) infections |CMV retinitis infections |Toxoplasmosis |Respiratory Failure

🧠 Guillain-Barré Syndrome (GBS): Respiratory function must always be monitored, as failure may occur silently without dyspnoea. ⚠️ Around 20% of patients need mechanical ventilation. 📏 Bedside test = Forced Vital Capacity (FVC); <1.5 L suggests ITU admission. 💉 IVIG within 2 weeks of onset is as effective as plasma exchange (Cochrane review) and more likely to be completed.

🩺 Initial Management of GBS

📖 About

• Acute onset ascending weakness + areflexia 🔽.
• Potentially life-threatening due to autonomic or respiratory failure.
• Also called Acute Inflammatory Demyelinating Polyneuropathy (AIDP).

🧬 Aetiology

• ⚔️ Autoimmune attack against peripheral nerves (molecular mimicry).
• 🌱 Infectious triggers: Campylobacter jejuni, CMV, HIV, HEV, EBV, Mycoplasma, Zika, Lyme.
• Pathology: multifocal demyelination + high CSF protein (albuminocytologic dissociation).

🔎 Subtypes of GBS

• AIDP (90%) – classic form, demyelinating.
• AMAN (5%) – acute motor axonal neuropathy, often after Campylobacter.
• Miller-Fisher (5%) – triad: ophthalmoplegia 👁️, ataxia 🚶, areflexia.
• AMSAN (1%) – motor + sensory axonal neuropathy.

⚠️ Clinical Features

• 🔼 Ascending weakness (legs → trunk → arms → cranial nerves).
• ❌ Areflexia.
• 🫁 Respiratory weakness ± need for ventilation.
• ❤️ Dysautonomia: BP swings, arrhythmias, pupillary changes.
• 🩻 Back pain, sensory loss, cranial neuropathies.
• 👀 Papilloedema possible due to high CSF protein.

🧪 Investigations

• 🧫 CSF: Protein ↑, normal WCC (may be normal early).
• ⚡ NCS: Slowed conduction, absent F-waves, conduction block.
• 🫀 ECG: monitor for arrhythmias.
• 🧬 Antibody testing rarely useful (anti-GD1a, anti-GQ1b in Miller-Fisher).

🩻 Differentials

• Spinal cord lesions (transverse myelitis).
• Myasthenia gravis, botulism.
• Tick paralysis, diphtheria, poliomyelitis.
• Acute porphyria.

🚨 Indications for ITU/Intubation

• FVC <15–20 ml/kg or <1 L.
• 🫁 Abnormal inspiratory/expiratory pressures.
• ❌ Severe bulbar weakness or impaired cough.
• 📉 Autonomic instability or abnormal gases.

💊 Management

• Specific: IVIG (within 2 weeks) or plasma exchange (within 4 weeks). 🚫 Steroids ineffective.
• Supportive: ITU if required, VTE prophylaxis, physiotherapy, speech therapy, nutrition support.
• Pain: Neuropathic analgesia (gabapentin, carbamazepine). Avoid amitriptyline (arrhythmia risk).

📈 Outcome

• Most improve within 12 months, but recovery may continue up to 5 years.
• 85% recover well; 15% left with disability.
• Poor prognosis: rapid onset, older age, preceding diarrhoea, severe initial weakness.

⚠️ Complications

• Bulbar dysfunction → aspiration, malnutrition.
• Autonomic storms → arrhythmias, BP swings.
• Immobility → pressure sores, DVT/PE, infections.

📚 References

• Diagnosis and Management of Guillain-Barré Syndrome in Ten Steps – Nat Rev Neurol

Cases — Guillain–Barré Syndrome (GBS)

• Case 1 — Classic Post-Infectious Ascending Weakness 🦵: A 32-year-old man develops tingling in his feet one week after a Campylobacter gastroenteritis. Over 3 days, he develops progressive ascending weakness, now unable to climb stairs. Exam: bilateral foot drop, absent ankle reflexes, intact cranial nerves. Diagnosis: Acute inflammatory demyelinating polyneuropathy (AIDP, most common GBS subtype). Management: Admit for monitoring; IV immunoglobulin (IVIG) or plasma exchange; monitor vital capacity regularly.
• Case 2 — Miller–Fisher Variant 👁️: A 45-year-old woman presents with acute diplopia and unsteady gait. Exam: ophthalmoplegia, ataxia, and areflexia, but normal limb strength. CSF shows albuminocytologic dissociation. Anti-GQ1b antibodies positive. Diagnosis: Miller–Fisher variant of GBS. Management: IVIG; supportive physiotherapy and rehabilitation.
• Case 3 — Severe GBS with Respiratory Involvement 🫁: A 28-year-old man presents with progressive ascending weakness, facial diplegia, and dysphagia. Exam: bilateral flaccid paralysis, absent reflexes, reduced single-breath count. Diagnosis: Severe GBS with bulbar and respiratory muscle involvement. Management: Admit to ICU; intubation and ventilation if vital capacity falls; IVIG or plasma exchange; multidisciplinary supportive care.

Teaching Commentary 🧠

GBS is an acute, immune-mediated polyneuropathy triggered by infections (e.g. Campylobacter, EBV, CMV, HIV) or rarely vaccination. Hallmarks: progressive symmetrical weakness (usually ascending), areflexia, mild sensory symptoms, autonomic instability (arrhythmias, BP swings). Investigations: - CSF: albuminocytologic dissociation (↑protein, normal cells). - Nerve conduction: demyelination (slowed conduction, conduction block). Complications: respiratory failure (20–30%), autonomic dysfunction. Treatment: IVIG or plasma exchange (equally effective); steroids are not helpful. Monitor in hospital until clear plateau or recovery.