From the Guidelines
The patient with membranous nephropathy should be treated with a combination of immunosuppressive therapy, including cyclosporin, and supportive care to reduce proteinuria and slow disease progression, as evidenced by the workshop recommendations 1. The patient has membranous nephropathy, which is causing nephrotic syndrome as evidenced by his facial puffiness, peripheral edema, hypoalbuminemia, and significant proteinuria. Initial treatment should include an ACE inhibitor or ARB to reduce proteinuria, such as lisinopril 10 mg daily or losartan 50 mg daily.
- A low-sodium diet (less than 2 grams daily) should be recommended to help manage edema.
- Since this is a 17-year-old with primary membranous nephropathy, immunosuppressive therapy should be considered, typically with a regimen of alternating monthly cycles of oral and intravenous corticosteroids plus cyclophosphamide, as cycling a cytotoxic agent with a corticosteroid over a 6-month period has been shown to both reduce proteinuria and slow disease progression 1.
- Before starting immunosuppression, testing for secondary causes should be completed, including hepatitis B and C, HIV, autoimmune disorders, and malignancy screening.
- Diuretics like furosemide 20-40 mg daily may be needed for symptomatic edema.
- Anticoagulation with warfarin or a direct oral anticoagulant should be considered if serum albumin is persistently below 2.5 g/dL due to increased thrombosis risk. Regular monitoring of renal function, proteinuria, and albumin levels is essential to assess treatment response.
- The prognosis of membranous nephropathy might also be influenced by racial origin, and the patient's proteinuria level, with low-risk patients having <4 g/day proteinuria, medium-risk patients having proteinuria consistently between 4 and 8 g/day, and high-risk patients having abnormal and/or deteriorating >8 g/day proteinuria 1.
From the Research
Patient Presentation
The patient is a 17-year-old boy presenting with progressive facial puffiness, fatigue, and decreased appetite for the past month. Physical examination shows periorbital and pretibial edema. Laboratory results indicate 4+ proteinuria, low albumin levels, and normal creatinine levels.
Diagnosis
The patient's diagnosis is consistent with membranous nephropathy, as evidenced by the renal biopsy showing a diffuse, granular pattern of IgG and C3 along the capillary loops and electron-dense immune deposits along the glomerular basement membrane.
Treatment Options
- Angiotensin-converting enzyme (ACE) inhibitors may be considered for treatment, as they have been shown to have a blood pressure-lowering independent anti-proteinuric effect 2, 3.
- Angiotensin receptor blockers (ARBs) may also be considered, as they have been shown to have similar efficacy to ACE inhibitors in reducing proteinuria and slowing renal disease progression 4, 5.
- The optimal dose of ACE inhibitors or ARBs for renoprotection is not well established, but higher doses may be associated with further reductions in proteinuria and improved renal outcomes 3.
Considerations
- ACE inhibitors are contraindicated in pregnancy due to fetal toxicity 2.
- ARBs may have a lower risk of adverse events, such as cough and angioedema, compared to ACE inhibitors 5.
- Sacubitril-valsartan, a combination of an ACE inhibitor and a neprilysin inhibitor, may be considered for patients with heart failure and reduced ejection fraction, but its use in patients with membranous nephropathy is not well established 6.
Key Points
- Membranous nephropathy is a cause of nephrotic syndrome, characterized by heavy proteinuria and low albumin levels.
- ACE inhibitors and ARBs may be considered for treatment, but the optimal dose and choice of agent are not well established.
- Further studies are needed to determine the efficacy and safety of different treatment options for patients with membranous nephropathy.