Minimal Change Disease (MCD)

Minimal change glomerulonephritis (lipoid nephrosis)

almost always nephrotic - >80% of cases in children <15y (most common age group is between 2 and 6 y) whereas ~28% of nephrotic $ in adults

Highly selective proteinuria (albuminuria)

maybe d/t NSAIDs or gold; rare associations with Hodgkin's lymphoma and thymoma

Pathophysiology:

caused by a primary defect in immunologic function, as suggested by its association with respiratory infections, immunizations, and atopic disorders, as well as its excellent response to steroid therapy. This immune dysfunction leads to overproduction of a specific cytokine (possibly IL-13) that causes direct damage to the podocytes, leading to retraction and fusion of the foot processes with reduced numbers of slit diaphragms. This damage causes increased translocation of albumin, but not other serum proteins, through the podocyte barrier, resulting in selective albuminuria

Dx

• 24-hour urine protein - 40 mg/m2/hour in children but now preferred initial test is a spot urine for protein/creatinine ratio >2
• Serum creatinine usually normal but may be increased slightly
• Serum albumin < 2.5 g/dL
• Elevated serum cholesterol and TGs
• normal C3 and C4

Rx

• prednisolone as outpatient (80% respond)

consider biopsy when there is :

1. hematuria,
2. HTN,
3. heart failure, or
4. if no response after 8 wks of prednisone (steroid resistant)