Membranous nephropathy in three paediatric patients

Membranous nephropathy in childhood is usually secondary to an underlying cause. Idiopathic membranous nephropathy is a rare cause of paediatric asymptomatic proteinuria/nephrotic syndrome. We reviewed the only three cases of membranous nephropathy followed in a paediatric hospital over the last ten years. All patients were female with mean age at diagnosis of 11.3 years (10-13 years). Patients 1 and 2 presented with steroid-resistant nephrotic syndrome. Patient 3 had a history of episodes of gross haematuria, and subnephrotic-range proteinuria refractory to enalapril and losartan. All patients had normal renal function. Patient 2 had hypertension and microscopic haematuria. Patients 1 and 2 underwent renal biopsy at an average of 51.5 days after initial symptoms; in patient 3, renal biopsy was performed seven years after initial presentation with episodes of gross haematuria, and five years after discovery of proteinuria. Histopathological features indicated membranous nephropathy; in patients 2 and 3, some findings suggested the coexistence of a systemic clinical condition. Secondary causes were sought in all patients. Six months after diagnosis, patient 1 developed facial skin lesions suggestive of discoid lupus erythematosus and later had positive autoantibodies (ANA, ENA, anti-SSA). Corticosteroids and angiotensin II receptor antagonists or angiotensin converting enzyme inhibitors were given to all patients. Those with nephritic syndrome required the addition of ciclosporin to achieve remission. At the latest evaluation (mean follow-up 31.3 months), patients 1 and 3 were in remission, and patient 2 had sub-nephrotic range proteinuria as the result of poor adherence to medication. All had normal renal function and blood pressure. All were receiving treatment with prednisolone and enalapril, and patients 1 and 2 were also receiving ciclosporin. Diagnosing idiopathic membranous nephropathy in children can be challenging. At least one of our patients had atypical features suggestive of an underlying cause so may have had secondary membranous nephropathy. Follow-up must continue, even after remission, with continued monitoring for underlying systemic disease. Treatment options are angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists, corticosteroids and immunosuppressive drugs such as ciclosporin.