Is IVIG (Intravenous Immunoglobulin) medically indicated for a patient with Myelin Oligodendrocyte Glycoprotein Antibody Disorder (MOGAD), mixed stress and urge urinary incontinence, and right arm weakness, with a negative MOG Ab IgG CBA-IFA Screen?

IVIG is NOT medically indicated for this patient with a negative MOG antibody test

The patient's negative MOG Ab IgG CBA-IFA Screen (<1:10) fundamentally contradicts the diagnosis of MOGAD, making IVIG therapy inappropriate and not standard of care for this presentation. 1

Critical Diagnostic Issue: Negative MOG Antibody Testing

• MOG-IgG seropositivity is the defining diagnostic criterion for MOGAD, and a negative test result essentially excludes this diagnosis 1
• The patient's MOG Ab IgG result of <1:10 is below any clinically significant threshold and does not support MOGAD 1
• International consensus guidelines emphasize that MOG-IgG testing using cell-based assays is the gold standard, and negative results should prompt reconsideration of the diagnosis 1

Important Caveat About Timing of Testing

• IVIG pretreatment can cause both false-negative and false-positive results in MOG antibody assays 1
• If this patient received IVIG prior to antibody testing, the negative result may be artifactually suppressed 1
• Re-testing should occur 1-3 months after IVIG administration or during treatment-free intervals to obtain accurate results 1
• MOG-IgG concentrations are also higher during acute attacks than during remission, so testing during active disease is preferred 1

Medical Indication Assessment

Without confirmed MOG-IgG seropositivity, IVIG therapy for presumed MOGAD is not medically indicated. The clinical presentation (right arm weakness, urinary incontinence) could represent numerous other neurological conditions requiring different diagnostic workup and treatment approaches.

If MOG-IgG Were Positive (Hypothetical Scenario)

• IVIG has been used successfully in confirmed MOGAD cases, with evidence supporting its use for relapse prevention 2
• The proposed dosing regimen (30g days 1-4 initially, then days 1-2 every 28 days) is within typical ranges used for antibody-mediated neurological disorders 1
• Subcutaneous immunoglobulin has shown promise in MOGAD with good tolerability and relapse prevention in small case series 2

Safety Concerns With Proposed IVIG Regimen

Renal Risk Factors Present

• The patient has laboratory abnormalities suggesting potential renal vulnerability: low total CO2 (18, indicating possible metabolic acidosis) and elevated anion gap (16) 3, 4, 5
• IVIG can cause acute oliguric renal failure, particularly in patients with pre-existing renal impairment, diabetes, older age, or when using sucrose-containing preparations 3, 4, 5
• Risk is heightened with high-dose IVIG (this patient would receive 30g initially, which is substantial) and rapid infusion rates 4, 5

IgA Level Considerations

• The patient's IgA level is 265 mg/dL, which is within normal range, reducing (but not eliminating) risk of anaphylactic reactions to IVIG 1
• IgA deficiency increases risk of severe anaphylaxis with IVIG due to anti-IgA antibodies, but this patient does not have documented IgA deficiency 1

Other Adverse Effects

• Common immediate adverse effects include headache, fever, chills, myalgia, chest tightness, and blood pressure changes 4
• Rare but serious complications include thromboembolic events, aseptic meningitis, and hemolytic anemia 4, 5
• Slow infusion rates and adequate hydration are essential to minimize risks 4, 5

Recommendation for Clinical Action

The appropriate next step is to:

1. Repeat MOG antibody testing if the current test was performed after any IVIG administration or during clinical remission 1
2. Obtain testing during an acute clinical episode when MOG-IgG titers are highest 1
3. Consider alternative diagnoses for the patient's neurological symptoms (right arm weakness, urinary incontinence) including multiple sclerosis, neuromyelitis optica spectrum disorder with AQP4 antibodies, or other demyelinating/neurological conditions 1
4. Do not proceed with IVIG therapy until a confirmed diagnosis is established with positive MOG-IgG serology 1

If Diagnosis Remains Uncertain

• Consider using a second, methodologically different cell-based assay for MOG-IgG testing to confirm results 1
• Seek expert consultation from a specialized neuroimmunology center 1
• Review MRI findings for features typical of MOGAD versus other demyelinating diseases 1

In summary: IVIG therapy is not medically indicated, not standard of care, and potentially harmful in a patient without confirmed MOG-IgG seropositivity. The negative antibody test fundamentally undermines the rationale for this expensive, invasive immunotherapy with significant adverse effect potential.