Nephrotic Syndrome for NP
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Nephrotic Syndrome for the Nurse Practitioner Licensing Exam
- Definition:
- Nephrotic syndrome is characterized by severe proteinuria (>3.5 g/day), hypoalbuminemia, edema, hyperlipidemia, and lipiduria. It results from damage to the glomerular filtration barrier, allowing large molecules like proteins to leak into urine.
- Etiology:
- Primary Causes:
- Minimal Change Disease (MCD): Most common in children. Presents with effacement of podocyte foot processes on electron microscopy.
- Focal Segmental Glomerulosclerosis (FSGS): More common in adults; associated with podocyte damage and segmental glomerulosclerosis.
- Membranous Nephropathy: Common in adults; due to immune complex deposition on the glomerular basement membrane.
- Secondary Causes:
- Diabetic Nephropathy: Leading cause in adults; characterized by thickened glomerular basement membrane.
- Lupus Nephritis: Autoimmune damage due to systemic lupus erythematosus (SLE).
- Amyloidosis: Deposition of amyloid proteins in the glomeruli.
- Pathophysiology:
- Damage to the glomerular filtration barrier, which includes the endothelial cells, glomerular basement membrane, and podocytes, allows proteins (especially albumin) to leak into urine.
- Protein loss leads to hypoalbuminemia, reducing plasma oncotic pressure and causing fluid to shift into the interstitial space, resulting in edema.
- The liver increases lipoprotein production in response to low protein levels, leading to hyperlipidemia.
- Clinical Features:
- Edema: Periorbital and lower extremity swelling.
- Frothy Urine: Due to proteinuria.
- Hypercoagulability: Loss of antithrombin III can predispose to thromboembolism.
- Infections: Loss of immunoglobulins in urine increases susceptibility to infections.
- Diagnosis:
- Urine Studies: Marked proteinuria on urinalysis; fatty casts or oval fat bodies may be seen.
- Serum Studies: Hypoalbuminemia, elevated cholesterol, and increased creatinine in cases of renal impairment.
- Renal Biopsy: Necessary for diagnosing the underlying cause in adults.
- Management:
- General Measures: Salt restriction, diuretics for edema, and statins for hyperlipidemia.
- Immunosuppressive Therapy: Steroids are the mainstay for MCD, while other conditions may require additional immunosuppressants (e.g., cyclophosphamide).
- Anticoagulation: Consider for those with significant thrombosis risk.
Key Points
- Nephrotic syndrome involves proteinuria, hypoalbuminemia, edema, and hyperlipidemia.
- Primary causes include Minimal Change Disease, FSGS, and Membranous Nephropathy.
- Secondary causes include diabetic nephropathy and lupus nephritis.
- Management includes diuretics, immunosuppressants, and anticoagulation.