What is the recommended treatment plan for a patient with Myelin Oligodendrocyte Glycoprotein Antibody Disorder (MOGAD) presenting with mixed stress and urge urinary incontinence, right arm weakness, and musculoskeletal symptoms?

Treatment Plan for MOGAD with Urinary Incontinence and Neurological Symptoms

Acute Attack Prevention with IVIG

IVIG (Privigen 30g) administered on days 1-4 initially, then days 1-2 every 4 weeks is an appropriate preventive therapy for MOGAD, particularly given the patient's relapsing risk factors and need to prevent further neurological damage. 1, 2

• IVIG has emerged as one of the most effective maintenance therapies for preventing relapses in MOGAD, with evidence showing it reduces the risk of second events when initiated early (HR 0.35,95% CI 0.14 to 0.88) 2
• The proposed dosing regimen aligns with standard IVIG protocols for MOGAD, though the initial 4-day loading dose (30g daily) followed by maintenance every 4 weeks is reasonable for attack prevention 1, 3
• Both intravenous and subcutaneous immunoglobulin formulations have demonstrated good tolerability and efficacy in preventing MOGAD relapses 3

Critical monitoring requirement: Obtain IgA levels before initiating IVIG, as IgA-deficient patients are at risk for anaphylactic reactions to blood products containing IgA 4

Acute Relapse Management Strategy

For acute MOGAD flares, high-dose IV methylprednisolone (1000 mg daily for 3-5 days) should be the first-line treatment, followed by a prolonged oral prednisone taper over 2-3 months to prevent early relapses. 5

• Short steroid dose packs for minor flares may be insufficient and increase relapse risk; MOGAD requires longer tapers than typical MS protocols 5
• For severe attacks unresponsive to steroids, plasma exchange (5-7 exchanges) or IVIG at 2 g/kg divided over 2-5 days should be implemented early 5
• Critical pitfall to avoid: Stopping steroids too quickly, as MOGAD has a particularly high risk of flare-ups after premature steroid cessation 5

Urinary Incontinence Management

For mixed stress and urge urinary incontinence in this MOGAD patient, mirabegron should be the preferred pharmacological option over antimuscarinics due to lower cognitive impairment risk and reduced urinary retention risk. 6

First-Line Approach:

• Behavioral therapies including bladder training, pelvic floor muscle training, and fluid management (typically 25% intake reduction) should be initiated alongside pharmacotherapy 6
• Bladder diaries should be used to document voiding behavior and treatment efficacy 6

Pharmacological Selection:

• Mirabegron is strongly preferred because it lacks impact on cognitive function (critical in MOGAD patients who may have baseline cognitive issues) and has lower urinary retention risk compared to antimuscarinics 6
• Regular blood pressure monitoring is required when using mirabegron, especially during initial treatment 6
• Ditropan (oxybutynin) as prescribed carries significant risks: Antimuscarinic medications should be used with extreme caution in neurogenic bladder conditions and can cause cognitive impairment that may worsen MOGAD-related cognitive issues 6

Critical Safety Measures:

• Post-void residual volume must be assessed before starting any antimuscarinic medication 6
• Antimuscarinics should be avoided if post-void residual volume exceeds 150 ml 6
• If antimuscarinics are used despite these concerns, regular assessment of post-void residual volume is mandatory 6

Muscle Spasm Management

Tizanidine at low doses (starting with half-tablet if needed) is appropriate for muscle spasms in MOGAD, with titration up to three times daily as tolerated. 4

• NSAIDs can be added for additional analgesia if there are no contraindications 4
• Monitor for excessive sedation or hypotension, which are common side effects that may necessitate dose adjustment 4

Monitoring and Follow-Up Protocol

Serial MRI scans of brain and spine every 3-6 months are recommended to establish new baseline, detect lesions, and monitor treatment effectiveness. 5, 7

• MOG-IgG serum concentrations vary with disease activity (higher during attacks) and treatment status (lower during immunosuppression), so timing of antibody testing is important 5
• If MOG-IgG testing becomes negative but clinical suspicion remains high, re-testing during acute attacks or treatment-free intervals is recommended 5
• BMP monitoring is appropriate given IVIG therapy and to assess renal function 4

Critical Treatment Pitfalls to Avoid

Do not treat this patient as multiple sclerosis, as some MS disease-modifying therapies might be ineffective or potentially harmful in MOGAD 5

• Avoid initiating antimuscarinic therapy without checking post-void residual volume 6
• Do not use antimuscarinics in patients with narrow-angle glaucoma or impaired gastric emptying 6
• Avoid stopping steroids abruptly during acute flares; MOGAD requires prolonged tapers 5

Alternative Maintenance Therapy Considerations

If IVIG proves ineffective or poorly tolerated, rituximab represents an alternative maintenance option with demonstrated efficacy (HR 0.25 for preventing second events) 2

• Rituximab may be particularly useful in refractory cases that continue to relapse despite IVIG 8
• Chronic low-dose corticosteroids as maintenance therapy are associated with higher relapse risk (HR 1.76) and should be avoided as primary prevention 2