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Other meanings of Minimal change disease

Nephrology

Minimal change disease

Minimal change disease (MCD) is a kidney disease characterized by nephrotic syndrome, most common in children, and is the leading cause of nephrotic syndrome in the pediatric population. It is called "minimal change" because the kidney tissue appears nearly normal under a light microscope, with only subtle changes visible under electron microscopy. MCD is typically responsive to corticosteroid therapy, and most patients achieve remission, though relapses are common.

~80%
of childhood nephrotic syndrome cases
Prevalence in children
~20%
of adult nephrotic syndrome cases
Prevalence in adults
90%
respond to corticosteroid therapy
Treatment response rate
1-3 per 100,000
annual incidence in children
Incidence
1

Pathophysiology and Histology

Minimal change disease is characterized by diffuse effacement of podocyte foot processes, visible only on electron microscopy, while light microscopy shows no significant glomerular abnormalities. The underlying mechanism involves T-cell dysfunction leading to the release of a circulating permeability factor that disrupts the glomerular filtration barrier. Recent research implicates B-cells and the cytokine IL-13 in the pathogenesis, as evidenced by response to rituximab. The glomerular basement membrane remains normal, and immune complex deposition is absent, distinguishing MCD from other nephrotic syndromes.

2

Clinical Presentation and Diagnosis

Patients present with the classic features of nephrotic syndrome: heavy proteinuria (>3.5 g/day in adults), hypoalbuminemia, edema, and hyperlipidemia. In children, the onset is often abrupt, with periorbital and peripheral edema, and the diagnosis is usually made clinically without a biopsy. In adults, a renal biopsy is recommended to confirm the diagnosis and rule out other causes, especially focal segmental glomerulosclerosis. Laboratory findings include lipiduria, and the urine sediment may show oval fat bodies. Hypertension and hematuria are uncommon, which helps differentiate MCD from other glomerular diseases.

3

Treatment and Prognosis

Corticosteroids are the mainstay of therapy, with prednisone given for 4-16 weeks, achieving remission in over 90% of children and about 80% of adults. For steroid-dependent or frequently relapsing cases, alternatives include cyclophosphamide, calcineurin inhibitors (e.g., tacrolimus), and mycophenolate mofetil. Rituximab has emerged as an effective steroid-sparing agent, particularly in children. The prognosis is excellent, with a low risk of progression to end-stage renal disease; however, relapses are common, and some patients require long-term immunosuppression. Complications include infections, thrombosis, and acute kidney injury, which require careful monitoring.

4

Lesser-known aspects

Minimal change disease can be secondary to nonsteroidal anti-inflammatory drugs, interferon therapy, or malignancies such as Hodgkin lymphoma, where it may be a paraneoplastic phenomenon. In such cases, treating the underlying cause often resolves the nephrotic syndrome. The disease has been associated with allergic reactions and immunizations, suggesting an immune-mediated trigger. Genetic studies have identified mutations in the NPHS2 gene in rare familial cases, though MCD is typically sporadic. The historical term "lipoid nephrosis" was used before electron microscopy revealed the podocyte changes, and the disease was once thought to be a purely metabolic disorder. In adults, MCD can occasionally progress to focal segmental glomerulosclerosis, which carries a worse prognosis.

Glossary

Podocyte
A specialized cell in the kidney glomerulus that forms part of the filtration barrier; its foot processes are effaced in MCD.
Nephrotic syndrome
A clinical condition characterized by proteinuria, hypoalbuminemia, edema, and hyperlipidemia.
Corticosteroids
Anti-inflammatory drugs, such as prednisone, used as first-line therapy for MCD.
Rituximab
A monoclonal antibody targeting B-cells, used as a steroid-sparing agent in relapsing MCD.

This article is for informational purposes only and does not replace professional medical advice.