What is the further treatment plan for a 5-year-old male with long segment myelitis and quadriplegia, MOG (Myelin Oligodendrocyte Glycoprotein) antibody positive, who improved completely with 5-day IV methylprednisolone (methylprednisolone) and is currently on oral Wysolone (prednisolone) 1mg/kg?

Treatment Plan for MOG-Antibody Positive Myelitis After Initial Steroid Response

This child requires immediate initiation of a steroid-sparing immunosuppressant (azathioprine 2 mg/kg/day or mycophenolate mofetil) while implementing a slow, structured prednisolone taper over 4-6 months to prevent relapse, which occurs in 43-50% of pediatric MOG-antibody disease cases. 1, 2, 3

Critical Error in Current Management

The current plan of only 1 week of oral prednisolone after complete recovery is dangerously inadequate and will likely trigger relapse:

• Abrupt steroid withdrawal after short courses commonly triggers disease flare in steroid-responsive conditions 1
• Courses longer than 3 weeks require gradual tapering to prevent both disease relapse and adrenal insufficiency 1
• MOG-antibody disease has a relapsing course in 43-50% of cases, with median 2.5 episodes per patient 2, 3

Immediate Management Steps

Week 1-2: Continue Current Dose

• Maintain prednisolone 1 mg/kg/day for at least 4-8 weeks total (not just 1 week) until complete clinical remission is confirmed 1
• Monitor for any return of neurological symptoms weekly 1

Week 2: Initiate Steroid-Sparing Agent

Start one of the following immediately (do not wait for steroid taper):

• Azathioprine 2 mg/kg/day (preferred first-line) 1, 2
• Mycophenolate mofetil (alternative if azathioprine contraindicated) 2

The evidence shows azathioprine combined with prednisolone reduces steroid-related side effects from 44% to 10% compared to prednisolone alone 1

Structured Tapering Protocol

Phase 1: Rapid Taper (Weeks 4-12)

• Reduce prednisolone by 5 mg every 2 weeks until reaching 10 mg/day 1
• Monitor disease activity markers every 2-4 weeks 1

Phase 2: Slow Taper (Months 3-6)

• Reduce by 1 mg every 4 weeks once at 10 mg/day 1
• This slow taper is critical to prevent relapse 1

Phase 3: Discontinuation

• Aim to discontinue prednisolone by 6 months while maintaining steroid-sparing agent 1

Relapse Management Protocol

If any neurological symptoms recur during taper:

• Immediately return to the pre-relapse prednisolone dose 1
• Maintain that dose for 4-8 weeks until disease control is re-established 1
• Consider escalating to IV methylprednisolone 1g daily for 3-5 days if severe 2
• Add IVIG or plasma exchange if steroid-refractory 2, 4

Monitoring Requirements

Clinical Monitoring

• Neurological examination every 2-4 weeks during first 6 months 1
• Watch for new weakness, sensory changes, visual symptoms, or bladder dysfunction 2

Laboratory Monitoring

• Complete blood count every 2 weeks initially (for azathioprine toxicity) 1
• Liver function tests monthly 1
• Consider repeat MOG-antibody testing in 6-12 months as serologies can evolve 1

Imaging Surveillance

• Repeat MRI spine at 3 and 6 months to assess for subclinical relapses 2
• MOG-antibody disease can have asymptomatic radiological relapses 5

Long-Term Maintenance Strategy

Duration of Immunosuppression

• Continue azathioprine/mycophenolate for minimum 12-24 months after achieving remission 1, 2
• Consider gradual withdrawal only after prolonged remission (>2 years) 1
• Monitor lifelong for disease recurrence as late relapses can occur 1

Escalation for Refractory Disease

If patient experiences breakthrough relapses despite azathioprine/mycophenolate:

• Rituximab (375 mg/m² weekly for 4 weeks, then maintenance every 6 months) 2
• IVIG (2 g/kg divided over 2-5 days monthly) has shown excellent response in MOG disease 4
• Ofatumumab (subcutaneous) for truly refractory cases 5

Prognostic Considerations

Favorable factors in this case:

• Complete response to initial IV methylprednisolone 2, 3
• 86% of MOG-antibody patients respond well to steroids 3
• Early identification and treatment improve outcomes 3

Risk factors requiring vigilance:

• Long-segment myelitis carries higher disability risk 2
• Pediatric onset may have different relapse patterns 2
• Quadriparesis at presentation indicates severe initial attack 3

Critical Pitfalls to Avoid

• Never abruptly stop steroids after 1 week - this is the most common cause of preventable relapse 1
• Never delay steroid-sparing agent - start within 2 weeks of initial treatment 1
• Never assume monophasic disease - 43-50% will relapse without maintenance therapy 2, 3
• Do not confuse with AQP4-positive NMOSD - MOG disease has better prognosis but still requires aggressive prevention 3