What is the initial therapy for a patient with ascending bilateral lower extremity weakness following an upper respiratory illness, suggestive of Guillain-Barré Syndrome (GBS)?

Initial Therapy for Guillain-Barré Syndrome

The AGACNP should initiate intravenous immunoglobulin (IVIG) at 0.4 g/kg/day for 5 consecutive days as the first-line treatment for this patient with suspected Guillain-Barré syndrome. 1, 2

Immediate Clinical Actions

Admit the patient immediately to an inpatient unit with capability for rapid transfer to ICU-level monitoring, as GBS can rapidly progress to respiratory failure in approximately 20% of cases. 1, 3, 2

Why IVIG is the Correct Answer (Option B)

• IVIG is the preferred first-line immunomodulatory treatment for GBS because it is easier to administer, more widely available, and has fewer complications compared to plasma exchange. 1, 2
• The standard dosing is 0.4 g/kg body weight daily for 5 consecutive days (total dose 2 g/kg). 1, 2
• IVIG and plasma exchange are equally effective, but IVIG is generally better tolerated and has lower discontinuation rates. 1

Why the Other Options Are Incorrect

Option A (Broad-spectrum antibiotics): Incorrect because GBS is an autoimmune post-infectious condition, not an active infection requiring antibiotics. The preceding upper respiratory infection has typically resolved before weakness onset. 1, 4

Option C (High-dose prednisone): Incorrect because corticosteroids alone are not recommended for idiopathic GBS. Eight randomized controlled trials showed no significant benefit, and oral corticosteroids were even associated with negative outcomes. 1, 5 The only exception is immune checkpoint inhibitor-related GBS, where steroids may be considered alongside IVIG or plasmapheresis. 1

Option D (MRI of the cervical spine): While MRI spine with and without contrast should be performed as part of the diagnostic workup to rule out compressive lesions, it is not a treatment and should not delay initiation of immunotherapy. 1, 2

Essential Concurrent Management Steps

Immediate Diagnostic Workup (While Initiating IVIG)

• Obtain neurology consultation immediately to confirm diagnosis and guide treatment. 1, 2
• Assess respiratory function using vital capacity, maximum inspiratory pressure, maximum expiratory pressure, and single breath count. 3, 2, 5
• Perform lumbar puncture for CSF analysis, which typically shows elevated protein with normal cell count (cytoalbuminous dissociation). 1, 2
• Order electrodiagnostic studies (nerve conduction studies and EMG) to evaluate polyneuropathy pattern. 1, 2

Critical Monitoring During Treatment

• Frequent neurological assessments to track disease progression, as maximum disability is typically reached within 2 weeks. 4, 3, 2
• Monitor for autonomic dysfunction including blood pressure/heart rate instability, cardiac arrhythmias, and bowel/bladder dysfunction. 4, 3, 2
• Serial pulmonary function testing to detect early respiratory compromise, as approximately 25% of patients require mechanical ventilation. 3, 6, 7

Common Pitfalls to Avoid

Do not wait for diagnostic confirmation before starting IVIG. The clinical presentation of rapidly progressive bilateral ascending weakness following an upper respiratory illness is sufficient to initiate treatment, as delays worsen outcomes. 1, 2

Do not use the 2-day IVIG regimen (2 g/kg over 2 days) as treatment-related fluctuations are more frequent compared to the standard 5-day regimen. 1, 2

Do not administer plasma exchange immediately after IVIG, as plasmapheresis will remove the immunoglobulin. 1

Do not assume normal reflexes exclude GBS. In the acute motor axonal neuropathy (AMAN) variant, reflexes may be normal or even exaggerated. 1

Alternative Treatment Option

Plasma exchange (200-250 ml plasma/kg body weight in 5 sessions over 1-2 weeks) is equally effective to IVIG and should be considered if IVIG is contraindicated, not tolerated, or unavailable. 1, 2 However, plasma exchange requires specialized equipment and monitoring, making it less practical as first-line therapy in most settings. 1

Prognosis and Expected Outcomes

• 60-80% of patients regain independent walking ability at 6 months after disease onset. 4, 3, 2
• Mortality remains 3-10% even with optimal treatment, primarily due to cardiovascular and respiratory complications. 4, 3, 2, 7
• Recovery can continue for more than 3 years after onset, so prolonged rehabilitation may be necessary. 1, 4, 3