Treatment of IgA Nephropathy with Focal Proliferative Changes, Creatinine 1.4, and 3g/day Proteinuria
The treatment of choice is optimized supportive care with ACE inhibitor or ARB therapy titrated to maximum tolerated dose, targeting blood pressure <125/75 mmHg, followed by a 6-month course of corticosteroid therapy if proteinuria persists ≥1 g/day after 3-6 months of optimized supportive care. 1
Initial Management: Optimized Supportive Care
Start with ACE inhibitor or ARB therapy immediately, as this patient has proteinuria >1 g/day, which mandates long-term RAS inhibition according to KDIGO guidelines 1. The creatinine of 1.4 (estimated GFR likely >50 mL/min/1.73m²) indicates preserved renal function sufficient for both supportive and immunosuppressive therapy 1.
Blood Pressure Targets
- Target BP <125/75 mmHg because proteinuria exceeds 1 g/day 1
- Titrate ACE inhibitor or ARB upward as far as tolerated to achieve proteinuria <1 g/day 1
- RAS inhibition probably decreases proteinuria (mean difference -0.71 g/24h) and increases creatinine clearance compared to symptomatic treatment alone 2
Corticosteroid Therapy After Supportive Care Trial
If proteinuria persists ≥1 g/day after 3-6 months of optimized supportive care, initiate a 6-month corticosteroid regimen 1. This recommendation applies because the patient has:
- GFR >50 mL/min/1.73m² (creatinine 1.4 is above the GFR <30 mL/min/1.73m² exclusion threshold) 1
- Persistent heavy proteinuria (3 g/day) indicating high risk of progression 3, 4
- Focal proliferative changes without crescentic disease 1
Corticosteroid Regimen Options
The KDIGO guideline recommends either of these regimens 1:
- IV methylprednisolone 1g for 3 consecutive days at months 1,3, and 5, plus oral prednisone 0.5 mg/kg every other day for 6 months 1, 5
- Oral prednisone starting at 0.8-1 mg/kg/day for 2 months, then reduced by 0.2 mg/kg/day per month for the next 4 months 1
Steroids significantly reduce proteinuria (from 2.0 g/24h to 1.0 g/24h at 6 months) and improve 6-year renal survival, with 20.9% versus 34.8% reaching 50% increase in serum creatinine compared to controls 5.
Therapies to AVOID in This Patient
Do NOT use corticosteroids combined with cyclophosphamide or azathioprine unless crescentic disease develops 1. This patient has focal proliferative changes, not crescentic IgAN (defined as >50% crescents with rapidly progressive deterioration) 1.
Do NOT use mycophenolate mofetil (MMF) as KDIGO guidelines recommend against MMF in IgAN 1. Evidence shows no benefit in Belgian and American trials, though some benefit may exist in Asian populations 1.
Do NOT use immunosuppressive therapy if GFR falls below 30 mL/min/1.73m² unless crescentic disease develops 1.
Adjunctive Therapies
Consider adding fish oil if proteinuria persists ≥1 g/day despite optimized supportive care 1. While evidence is conflicting, there is little risk with this intervention 1.
Do NOT perform tonsillectomy routinely, as evidence is limited to Japanese populations and not generalizable 1, 2.
Do NOT use antiplatelet agents (dipyridamole, warfarin) as evidence shows no benefit and adherence is difficult 1.
Critical Monitoring Points
- Reassess proteinuria at 3-6 months after starting ACE inhibitor/ARB to determine need for corticosteroids 1
- Monitor for steroid-related adverse events including glucose intolerance, hypertension, and infection risk 1
- Proteinuria reduction to <1 g/day is associated with favorable long-term outcomes regardless of how achieved 1, 3, 4
- The product of proteinuria duration and magnitude correlates strongly with progression; early aggressive treatment is warranted 3
Key Pitfall to Avoid
Do not delay ACE inhibitor/ARB therapy while waiting to assess disease trajectory. With 3g/day proteinuria, this patient has 25-fold faster decline in renal function compared to those with <500 mg/day proteinuria 3. Immediate RAS blockade is essential, with corticosteroids added if proteinuria remains elevated after adequate supportive care trial 1.