01/05/2026
Intravenous Immunoglobulin (IVIG)
Core concept and mechanisms
IVIG is pooled human IgG used as immunomodulatory therapy. It acts via Fc receptor blockade, anti-idiotype antibodies that neutralize pathogenic autoantibodies, complement inhibition (↓ C3/C5 activation), modulation of B- and T-cell activity, and effects on cytokine networks. Net effect: rapid dampening of autoimmune inflammation.
Indications (anchor list + context)
Guillain–Barré syndrome (GBS)
Chronic inflammatory demyelinating polyneuropathy (CIDP)
Myasthenia gravis (especially crisis)
Kawasaki disease
Immune thrombocytopenia (ITP)
Not routine for multiple sclerosis
Additional high-yield neurologic contexts (use case–dependent, specialist-guided): acute exacerbations of certain autoimmune neuropathies or when plasma exchange (PLEX) is not feasible.
Disease-specific pearls
Guillain–Barré syndrome (GBS)
Who to treat: Non-ambulatory within 4 weeks; ambulatory with progression within 2 weeks.
Dose: 0.4 g/kg/day × 5 days (total 2 g/kg).
IVIG vs PLEX: Equivalent efficacy; choose one. Do not combine routinely.
Second course: Consider only if clear treatment-related fluctuation or poor response (evidence mixed; specialist decision).
Respiratory monitoring: Serial FVC/NIF; IVIG does not replace ICU vigilance.
Chronic inflammatory demyelinating polyneuropathy (CIDP)
Induction: 2 g/kg over 2–5 days.
Maintenance: 0.4–1 g/kg every 3–4 weeks; titrate to the lowest effective dose/interval.
Guideline position: First-line alongside steroids and PLEX.
Objective response required: strength, disability scales; if no benefit after adequate trial, stop.
Myasthenia gravis (MG)
Indication: Myasthenic crisis or severe exacerbation.
Dose: 2 g/kg over 2–5 days.
IVIG vs PLEX: Similar short-term benefit; PLEX may act faster, IVIG easier logistically.
Maintenance: Not routine; reserve for selected refractory cases.
Key non-neurologic anchors
Kawasaki disease: 2 g/kg once + aspirin (reduces coronary complications).
Immune thrombocytopenia (ITP): 1 g/kg for 1–2 days when rapid platelet rise is needed.
Where IVIG is not routine
Multiple sclerosis: Not a standard disease-modifying therapy; may be considered only in limited scenarios (e.g., pregnancy/postpartum when alternatives are unsuitable).
Dosing and administration details
Total dose target: ~2 g/kg per course for most autoimmune neurologic uses.
Weighting: Use ideal/adjusted body weight in obesity.
Infusion: Start slow, titrate up per product protocol; adequate hydration reduces renal/thrombotic risk.
Premedication: Acetaminophen ± antihistamine; consider steroids in prior reactions.
Monitoring (before, during, after)
Baseline: CBC, creatinine, LFTs; assess thrombotic risk.
During infusion: vitals, symptoms (headache, chest pain).
After: hemoglobin (for hemolysis), renal function, clinical response.
Adverse effects and risk mitigation
Common: headache, fever, chills, myalgia.
Aseptic meningitis: severe headache/photophobia—more with high dose/rapid rate → slow infusion, hydrate.
Thromboembolism: stroke/MI/DVT risk—avoid rapid rates, hydrate, caution in elderly/vascular disease.
Renal injury: especially sucrose-containing products—prefer low-osmolar/sucrose-free formulations, slow rate.
Hemolysis: monitor Hb; higher risk in non-O blood groups and high cumulative doses.
Anaphylaxis: rare; higher risk in IgA deficiency with anti-IgA antibodies → consider IgA-depleted products.
Practical decision points
IVIG vs PLEX selection
Choose IVIG when vascular access is difficult, hemodynamic instability, or limited PLEX availability.
Choose PLEX when very rapid effect is desired (e.g., fulminant MG), or prior IVIG non-response.
Do not combine IVIG and PLEX routinely (PLEX can remove infused IgG).
Duration discipline: Prophylaxis vs treatment concept does not apply here—IVIG is a course-based immunotherapy; repeat only if objective benefit.
Special populations
Elderly / vascular disease: higher thrombotic risk—use slower rates, ensure hydration.
Renal impairment: avoid sucrose formulations; careful dosing and monitoring.
Pregnancy: IVIG is generally considered safe and is often preferred when other immunotherapies are contraindicated.
