Minimal Change Disease (MCD)
Minimal Change Disease is the most common cause of nephrotic syndrome in children. It is characterized by selective proteinuria (albuminuria) and excellent response to corticosteroid therapy.
1. Pathological Features
| Examination | Findings |
|---|---|
| Light Microscopy (LM) | Normal (hence the name “minimal change”). |
| Immunofluorescence (IF) | Negative (no immune complex deposits). |
| Electron Microscopy (EM) | Diffuse effacement (flattening) of podocyte foot processes. |
2. Exam Must-Knows
- Pathogenesis: Likely caused by T-cell dysfunction leading to cytokine-mediated damage to podocytes, resulting in the loss of their polyanionic charge (which normally repels albumin).
- Clinical Associations: Can be primary (idiopathic) or secondary. Secondary causes include Hodgkin Lymphoma (due to cytokines) and the use of NSAIDs.
- Prognosis: Excellent in children; often treated empirically with steroids without a kidney biopsy.
Pathology Board Hint: If a board question describes a child with generalized edema and massive proteinuria but a “normal” appearing glomerulus on light microscopy, think MCD immediately. The crucial diagnostic test here is electron microscopy, which will show the podocyte effacement.