Minimal change disease
Minimal change disease is a podocytopathy with normal light microscopy and diffuse foot-process effacement on electron microscopy, the leading cause of nephrotic syndrome in children and 10-15% of cases in adults. High-dose prednisone is first-line therapy, producing remission in over 90% of children and 80-90% of adults, though relapse is common.
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What this article covers
- Overview
A podocytopathy with a deceptively normal biopsy: minimal change disease (MCD, also called minimal change glomerulopathy) is defined by an absence of structural glomerular abnormality on light…
- Epidemiology
Age-dependent proportion of nephrotic syndrome: MCD causes 70% to 90% of nephrotic syndrome in children younger than 10 years, about 50% in adolescents and young adults, and less than 20% of adults…
- Risk factors
Age under 10 years: the dominant epidemiologic risk group, in whom MCD is presumed without biopsy in a typical presentation.
- Pathophysiology
Podocyte foot-process effacement without structural scarring: the defining lesion is diffuse fusion of podocyte foot processes visible only by electron microscopy, distinguishing MCD from focal…
- Clinical features
Sudden-onset nephrotic syndrome is the hallmark presentation: abrupt edema progressing over days to anasarca in untreated cases, distinguishing MCD from the slower edema onset typical of membranous nephropathy.
- Differential diagnosis
Focal segmental glomerulosclerosis: distinguished by segmental glomerulosclerosis on light microscopy, which MCD lacks, and by a lower, slower glucocorticoid response.
- Diagnosis
Diagnosis is confirmed by kidney biopsy showing normal glomeruli on light microscopy, negative immunofluorescence, and diffuse podocyte foot-process effacement on electron microscopy; in a typical…
- Management
First, start conservative measures in every patient alongside immunosuppression: Lisinopril, start 2.5-5 mg PO daily titrated to the maximal tolerated dose (or losartan 50-100 mg PO daily), for proteinuria and blood pressure control.
- Complications
Acute kidney injury: occurs in up to 25% of adults, more common with older age, hypertension, low albumin, and heavy proteinuria; usually reversible with remission.
- Prognosis
Excellent long-term kidney function in most patients: the great majority of patients with MCD maintain normal long-term kidney function, in sharp contrast to FSGS.
- Prevention
No validated primary prevention exists for idiopathic MCD; prevention efforts focus on preventing relapse and limiting treatment toxicity in known disease.
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Focal segmental glomerulosclerosis is a podocytopathy causing segmental glomerular scarring on biopsy, presenting with nephrotic-range proteinuria and accounting for up to 40% of primary nephrotic syndrome in adults. Diagnosis requires kidney biopsy, and primary disease is treated with high-dose glucocorticoids followed by calcineurin inhibitors for resistant cases.
- Membranous nephropathy
Membranous nephropathy is the leading cause of nephrotic syndrome in white adults, most often a primary autoimmune disease driven by anti-PLA2R antibodies against a podocyte antigen, diagnosed by kidney biopsy or noninvasively by anti-PLA2R serology. Patients with persistent nephrotic-range proteinuria after a period of conservative observation are treated with cyclical glucocorticoid-cyclophosphamide, a calcineurin inhibitor, or rituximab.
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- Approach to hematuria
Hematuria is present in urine when at least 3 erythrocytes per high-power field are seen on microscopy, and the first branch point is glomerular versus nonglomerular bleeding, based on erythrocyte morphology and casts. Gross hematuria always requires urologic evaluation and cystoscopy, asymptomatic microscopic hematuria is risk-stratified by American Urological Association criteria to select repeat testing, imaging, or cystoscopy, and glomerular hematuria is treated with disease-specific immunosuppression after biopsy.