Management of Retinal Vasculitis in Granulomatosis with Polyangiitis (GPA)
For a patient with retinal vasculitis due to GPA confirmed by positive C-ANCA and anti-PR3, with bilateral ear pain and normal renal/liver function, the recommended treatment is rituximab plus glucocorticoids for remission induction. 1
Disease Classification and Assessment
This patient presents with:
- Retinal vasculitis causing blurry vision
- Bilateral ear pain
- Positive C-ANCA and anti-PR3 antibodies
- No joint pain, rash, shortness of breath, or chest pain
- Normal renal and liver function
These findings are consistent with Granulomatosis with Polyangiitis (GPA) with ocular and ear involvement but without apparent renal or pulmonary manifestations.
Treatment Algorithm
Step 1: Remission Induction Therapy
First-line therapy:
- Rituximab: 375 mg/m² once weekly for 4 weeks 1
- Glucocorticoids: Initial high-dose (typically 1 mg/kg/day, not exceeding 80 mg/day) with pre-specified tapering schedule 1
Rituximab is preferred over cyclophosphamide in this case because:
- The patient has extrarenal manifestations (retinal vasculitis and ear involvement)
- The patient has PR3-ANCA positivity, which responds well to rituximab 1
- The patient has normal renal function, and rituximab has shown excellent efficacy in non-renal manifestations 2
Step 2: Maintenance Therapy (after achieving remission)
After achieving remission (typically 3-6 months):
- Rituximab maintenance: 500 mg every 6 months for 18-24 months 1 OR
- Azathioprine: 1.5-2 mg/kg/day with low-dose glucocorticoids 1
The optimal duration of maintenance therapy is between 18 months and 4 years after induction of remission 1.
Monitoring and Follow-up
- Regular ophthalmologic examinations to assess retinal vasculitis response
- ENT evaluation for ear involvement
- Monitor ANCA titers, though treatment decisions should not be based solely on ANCA results 1
- Regular laboratory monitoring for treatment-related toxicity
- Pneumocystis jirovecii pneumonia prophylaxis is recommended for patients receiving rituximab 1
Special Considerations
Ocular Involvement
- Retinal vasculitis requires aggressive immunosuppressive therapy to prevent vision loss 2
- Ophthalmology consultation should be maintained throughout treatment
Ear Involvement
- Bilateral ear pain suggests otitis media, a common manifestation of GPA
- ENT specialist involvement is recommended for management of ear manifestations 2
Disease Monitoring
- Clinical assessment of disease activity using standardized tools (e.g., Birmingham Vasculitis Activity Score)
- Regular monitoring for potential relapse, especially since PR3-ANCA positive patients have higher relapse rates 1, 3
Treatment of Relapse
If relapse occurs after successful remission induction:
- For severe relapse: Rituximab is conditionally recommended over cyclophosphamide 1
- For non-severe relapse: Consider adjusting current immunosuppressive therapy based on clinical features 1
Potential Pitfalls and Caveats
Delayed treatment: Do not delay immunosuppressive therapy while waiting for additional testing in a patient with compatible clinical presentation and positive ANCA serology 1
Infection risk: Patients on rituximab have increased risk of infections, particularly hypogammaglobulinemia. Monitor immunoglobulin levels periodically 4
Infusion reactions: Premedicate with antihistamine and acetaminophen before rituximab infusions to minimize infusion-related reactions 4
Incomplete treatment: Inadequate immunosuppression may lead to disease progression and permanent organ damage, particularly with ocular involvement 2
Treatment duration: Premature discontinuation of maintenance therapy increases relapse risk, especially in PR3-ANCA positive patients 1
By following this treatment approach, the risk of permanent vision loss and progression to other organ involvement can be minimized while optimizing the patient's quality of life.