Minimal Change Disease

GENERAL PRINCIPLES

Epidemiology

MCD is the most common cause of nephrotic syndrome in children but has a second peak in adults aged 50-60 years. Typically, there is sudden onset of proteinuria with hypertension and edema, although renal insufficiency is unusual.

Associated Conditions

Secondary forms of MCD may accompany certain malignancies (Hodgkin disease and solid tumors being the most common) and therefore, patients in the appropriate age group should undergo further cancer screening. A form of interstitial nephritis associated with NSAID use may also be associated with MCD.

DIAGNOSIS

The kidney biopsy reveals normal glomeruli on light microscopy and negative immunofluorescence. Electron microscopy shows complete foot process effacement. This may have a similar appearance to early onset FSGS and thus be difficult to differentiate.

TREATMENT

• In adults, treatment with high-dose oral prednisone at 1 mg/kg daily (not exceeding 80 mg∕d) or 2 mg/kg on alternate days (not exceeding 120 mg, every other day) may induce remission (i.e., decrease in proteinuria) after a minimum of 4 weeks, but can require up to 16 weeks of therapy. Prednisone can then be tapered off over a 6-month period.

• Relapse may occur in up to 75% of adults. Reinstitution of prednisone is often effective. If the patient is steroid dependent or steroid resistant, cytotoxic agents may be needed, with cyclophosphamide 2 mg/kg/d or chlorambucil 0.2 mg/kg/d. Cyclosporine 3-5 mg/kg/d or mycophenolate mofetil 1000 mg twice a day for 2 years can be considered as alternative therapies.¹⁶ Rituximab may be beneficial in frequently relapsing or glucocorticoid-dependent MCD.¹⁷