What is the recommended treatment for a patient with Acute Inflammatory Demyelinating Polyneuropathy (AIDP), also known as Guillain-Barré Syndrome?

Treatment of Acute Inflammatory Demyelinating Polyneuropathy (AIDP)

For patients with AIDP who cannot walk independently, initiate intravenous immunoglobulin (IVIg) at 0.4 g/kg/day for 5 consecutive days (total dose 2 g/kg) or plasma exchange as first-line treatment, with IVIg generally preferred due to easier administration and wider availability. 1, 2, 3

Immediate Assessment and Triage

When AIDP is suspected, rapid evaluation is critical:

• Admit all patients to an inpatient unit with capability for rapid ICU transfer, as respiratory failure can develop quickly even without dyspnea 1, 2
• Obtain immediate neurology consultation 1
• Monitor respiratory function closely using vital capacity, maximum inspiratory/expiratory pressures, and the "20/30/40 rule": patients are at risk if vital capacity <20 mL/kg, maximum inspiratory pressure <30 cmH₂O, or maximum expiratory pressure <40 cmH₂O 2
• Perform frequent neurologic examinations to assess progression 1

Diagnostic Workup

Complete the following studies to confirm diagnosis and rule out mimics:

• MRI of spine with/without contrast to exclude compressive lesions and evaluate for nerve root enhancement 1
• Lumbar puncture: CSF typically shows elevated protein with normal or mildly elevated white blood cell count (albuminocytologic dissociation) 1
• Electrodiagnostic studies (nerve conduction studies and EMG) to confirm polyneuropathy and distinguish AIDP from axonal variants 1
• Serum antiganglioside antibody testing for GBS subtypes, including anti-GQ1b for Miller Fisher variant 1
• Pulmonary function testing with negative inspiratory force (NIF) or vital capacity (VC) 1

Treatment Selection Algorithm

Grade 2 (Moderate symptoms with some ADL interference):

• Discontinue any immune checkpoint inhibitors if applicable 1
• Initiate IVIg 0.4 g/kg/day for 5 days if patient has difficulty walking or symptoms are concerning 2, 3
• Consider plasma exchange (12-15 L over 4-5 exchanges in 1-2 weeks) as an alternative if IVIg is contraindicated 3

Grade 3-4 (Severe: limiting self-care, weakness limiting walking, dysphagia, facial/respiratory weakness, or rapidly progressive):

• Admit to ICU-capable unit immediately 1
• Start IVIg 0.4 g/kg/day for 5 days (total 2 g/kg) OR plasma exchange 1
• Do NOT combine plasma exchange followed immediately by IVIg, as plasmapheresis will remove the immunoglobulin 1, 3

Corticosteroid Considerations

Corticosteroids are NOT recommended for idiopathic AIDP, as they have not shown benefit and may worsen outcomes 2, 3, 4. However, there is one important exception:

• For immune checkpoint inhibitor-related AIDP only: Consider methylprednisolone 2-4 mg/kg/day or pulse dosing (1 g/day for 5 days) along with IVIg or plasmapheresis, followed by slow taper over 4-6 weeks 1

This represents a key divergence in the evidence: checkpoint inhibitor-related cases may benefit from concurrent steroids, while classic AIDP should not receive them 1.

IVIg Administration Details

• Dose calculation: Use ideal body weight, not actual body weight, as IVIg distributes in plasma and extracellular fluid spaces that correlate with lean body mass 2
• Check IgA levels before first infusion: IgA deficiency increases anaphylaxis risk; use IgA-reduced preparations if deficiency confirmed 2
• Timing: Initiate within 2 weeks of symptom onset for maximum benefit, though treatment up to 4 weeks may still help 2, 3
• Infusion schedule: When total dose exceeds 80 grams, may divide over 3-5 days at 0.4 g/kg to improve tolerability 2

Medications to Avoid

Strictly avoid the following agents as they worsen neuromuscular function:

• β-blockers
• IV magnesium
• Fluoroquinolones
• Aminoglycosides
• Macrolides 1, 2

Supportive Care and Complication Management

Respiratory Management:

• Monitor for autonomic dysfunction including cardiac arrhythmias and blood pressure instability 1
• Perform frequent pulmonary function assessments 1
• Consider early intubation if respiratory parameters deteriorate 5

Pain Management:

• Use gabapentinoids (gabapentin, pregabalin), tricyclic antidepressants, or duloxetine for neuropathic pain 1, 3
• Avoid opioids for neuropathic pain management 1

Other Supportive Measures:

• Treat constipation/ileus proactively 1
• Provide DVT prophylaxis 2
• Assess for dysphagia and provide nutritional support as needed 2

Treatment-Related Fluctuations and Poor Response

• Treatment-related fluctuations (TRFs) occur in 6-10% of patients within 2 months of initial improvement 2
• For TRFs: Repeat the full course of IVIg or plasma exchange 1, 2
• Second IVIg course is NOT recommended for patients with poor prognosis who haven't shown initial response 3
• About 40% of patients do not improve in first 4 weeks, which doesn't necessarily indicate treatment failure 2
• Consider diagnosis change to acute-onset CIDP if progression continues beyond 8 weeks, occurring in ~5% of initially diagnosed GBS patients 3

Prognosis

• 80% of patients regain walking ability at 6 months 2
• Mortality is 3-10%, primarily from cardiovascular and respiratory complications 1, 2
• Use the modified Erasmus GBS Outcome Score (mEGOS) to predict functional outcome 3
• Use the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess ventilation risk 3