I have myasthenia gravis and a history of bronchial asthma, recently had an exacerbation of symptoms, and after failing high-dose steroid treatment, I received 155 grams of Intravenous Immunoglobulin (IVIG) therapy from three different brands: Ivnex (Intravenous Immunoglobulin), Ighex (Intravenous Immunoglobulin) which I stopped due to a reaction, and Proglob (Intravenous Immunoglobulin), what are the potential mistakes or errors in my treatment regimen?

Critical Errors in Your IVIG Treatment for Myasthenia Gravis

Your IVIG dosing was significantly underdosed at 155 grams when you required 190 grams (2 g/kg × 95 kg actual body weight), representing an 18% underdose that likely contributed to inadequate therapeutic response. 1, 2

Primary Dosing Error

The fundamental mistake was calculating IVIG based on ideal body weight (80 kg) instead of actual body weight (95 kg). The established standard for myasthenia gravis exacerbations is 2 g/kg total dose over 5 days, which should have been:

• Correct dose: 190 grams total (2 g/kg × 95 kg = 190 g) 1, 2
• Your dose: 155 grams total
• Deficit: 35 grams (18% underdosed)

The guideline explicitly states IVIG should be administered as 0.4 g/kg/day for 5 consecutive days for a total of 2 g/kg, and this calculation uses actual body weight, not ideal body weight. 1, 2

Brand Switching During Treatment Course

Switching between three different IVIG brands (Ivnex, Ighex, Proglob) during a single treatment course is problematic because:

• Different formulations have varying IgG subclass distributions, stabilizers, and osmolality that can affect tolerability and efficacy 2
• Your reaction to Ighex requiring discontinuation disrupted the continuous 5-day treatment protocol 2
• The standard approach is to complete the entire 5-day course with a single brand unless severe adverse reactions occur 1

Timing and Indication Assessment

IVIG is specifically indicated for Grade 3-4 myasthenic exacerbations with severe generalized weakness, respiratory insufficiency, or dysphagia requiring hospitalization. 1, 2 Your description of "exacerbation of symptoms" that "didn't work" with high-dose steroids suggests this was appropriate, but critical details are missing:

• Did you have respiratory compromise requiring pulmonary function monitoring (negative inspiratory force, vital capacity)? 1, 3
• Did you have bulbar symptoms (dysphagia, facial weakness, speech difficulties)? 1, 3
• Were you hospitalized with ICU-level monitoring during IVIG administration? 1, 2

If you received IVIG as outpatient therapy or without severe Grade 3-4 symptoms, this represents inappropriate use - IVIG should be reserved for acute crisis situations, not chronic maintenance. 4, 2

Concurrent Medication Management Errors

Critical gaps in your treatment approach:

Pyridostigmine Management

• You should have been started on or optimized pyridostigmine (30 mg orally three times daily, titrating to maximum 120 mg four times daily) before escalating to IVIG 1, 4
• Pyridostigmine should be continued during IVIG administration unless you were intubated 4, 2
• No mention of pyridostigmine use suggests a fundamental gap in stepwise management 1

Corticosteroid Dosing

• "High steroid" is vague - the guideline specifies prednisone 1-1.5 mg/kg/day orally, which for your 95 kg weight should be 95-142.5 mg daily 1, 4
• Corticosteroids must be continued concurrently during IVIG administration, not stopped 1, 2
• Steroids should be tapered gradually over 4-6 weeks based on symptom improvement, not abruptly discontinued 1

Medications to Avoid with Asthma History

Your bronchial asthma history creates a critical medication safety concern. You must strictly avoid:

• β-blockers (can worsen both myasthenia AND asthma) 1, 4
• Fluoroquinolones, aminoglycosides, macrolides 1, 4
• IV magnesium 1, 4

Missing Diagnostic and Monitoring Elements

Your EMG report alone is insufficient. The complete workup for myasthenic exacerbation should include:

• Acetylcholine receptor (AChR) antibodies and antistriated muscle antibodies 1, 4
• If AChR negative: muscle-specific kinase (MuSK) and lipoprotein-related protein 4 (LRP4) antibodies 1, 4
• Pulmonary function testing with negative inspiratory force (NIF) and vital capacity (VC) - absolutely essential given your respiratory history 1, 3
• CPK, aldolase, ESR, CRP to evaluate for concurrent myositis 1
• Troponin T and ECG to rule out myocarditis (can occur with myasthenia exacerbations) 1

During IVIG administration, you should have received:

• Frequent pulmonary function monitoring (NIF/VC measurements) 1, 3, 2
• Daily neurologic examinations 1, 2
• ICU-level monitoring if Grade 3-4 symptoms 1, 2

IgA Deficiency Screening Omission

Before first IVIG infusion, serum IgA levels should have been checked - IgA deficiency can cause severe anaphylaxis with IVIG, requiring IgA-reduced preparations. 2 Your reaction to Ighex may have been related to this if not screened.

Inappropriate Use as Maintenance Therapy

If you are receiving IVIG on a regular/maintenance schedule, this is explicitly contraindicated. Current guidelines from the American Academy of Neurology state that immune globulin should NOT be used for chronic maintenance therapy in myasthenia gravis. 4

While older research studies from 1995-2014 5, 6, 7, 8 suggested potential benefit of maintenance IVIG, the most recent 2026 guidelines definitively recommend against this practice. 4 IVIG is reserved exclusively for acute exacerbations or crisis situations. 4, 2

Correct Management Algorithm Going Forward

For future exacerbations, the proper sequence is:

1. Grade 2 symptoms (moderate weakness interfering with activities):

   • Optimize pyridostigmine (30-120 mg four times daily) 1, 4
   • Add prednisone 1-1.5 mg/kg/day (95-142.5 mg for you) 1, 4
   • Monitor closely with neurology follow-up 4
   • Do NOT use IVIG at this stage 4, 2

2. Grade 3-4 symptoms (severe weakness, respiratory compromise, dysphagia):

   • Immediate hospitalization with ICU monitoring 1, 2
   • IVIG 0.4 g/kg/day × 5 days (38 grams daily for 5 days = 190 grams total) OR plasmapheresis 1, 2
   • Continue corticosteroids concurrently 1, 2
   • Maintain pyridostigmine unless intubated 4, 2
   • Frequent NIF/VC monitoring 1, 3, 2
   • Daily neurologic examinations 1, 2

3. If inadequate response after 2-4 weeks:

   • Consider steroid-sparing agents (azathioprine, mycophenolate) 2, 9
   • Rituximab only for refractory cases after failing standard immunosuppression 2, 9

Common Pitfalls You Encountered

• Never calculate IVIG dose on ideal body weight - always use actual body weight 1, 2
• Never switch IVIG brands mid-course unless severe reaction - complete 5 days with single formulation 2
• Never use IVIG for chronic maintenance - only for acute Grade 3-4 exacerbations 4, 2
• Never stop corticosteroids during IVIG - continue concurrently and taper gradually after 1, 2
• Never skip pulmonary function monitoring - especially critical with your asthma history 1, 3
• Never omit pyridostigmine trial before escalating to IVIG 1, 4