Minimal change disease

Definition

Minimal change disease (lipoid nephrosis) is a glomerulopathy with abrupt-onset nephrotic syndrome in which the glomeruli appear normal on light microscopy. The only typical finding is diffuse effacement of podocyte foot processes on electron microscopy.

Occurrence & epidemiology

In children older than one year it is the most common cause of nephrotic syndrome (70–90% of childhood cases); the mean age at diagnosis of childhood nephrotic syndrome is 5–6 years. In adults it accounts for about 15% of nephrotic syndromes.

Aetiopathogenesis

The cause is almost always unknown. A T-cell-mediated disorder with circulating factors that alter the glomerular charge barrier is suspected; as a result, mainly albumin is lost (selective proteinuria). Rarely the disease is secondary, especially associated with NSAID use and hematologic cancers such as Hodgkin lymphoma.

Clinical features

Typical is a rapidly developing nephrotic syndrome with edema, usually without hypertension or azotemia. More than half of adults have microscopic hematuria. Acute kidney injury may occur, particularly in people older than 50 to 60 years. Complications are those of nephrotic syndrome, such as infections and thromboembolism.

Histology

Light microscopy: normal glomeruli. Immunofluorescence: no deposits of IgG, IgA, IgM or complement. Electron microscopy: edema and diffuse effacement of podocyte foot processes.

Diagnosis

• Children: with a typical presentation, the diagnosis is usually made without biopsy: sudden-onset nephrotic-range proteinuria (≥ 3 g/day), mainly albumin, normal kidney function and no nephritic sediment.
• Adults and atypical presentations: kidney biopsy with light, immunofluorescence and electron microscopy
• Laboratory tests as in nephrotic syndrome: protein-to-creatinine ratio, serum albumin, lipids, creatinine; in adults, search for secondary causes (drug history, lymphoma)

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Further reading (open access)

1. MSD Manual Professional: Minimal Change Disease
2. MSD Manual Professional: Overview of Nephrotic Syndrome

Cross-references