From the Guidelines
Nephrotic syndrome is caused by several distinct etiologies, including primary causes such as minimal change disease, focal segmental glomerulosclerosis (FSGS), membranous nephropathy, and membranoproliferative glomerulonephritis, as well as secondary causes like diabetes mellitus, systemic lupus erythematosus, and infections, as noted in the 2023 study by 1.
Primary Causes
- Minimal change disease: most common in children
- Focal segmental glomerulosclerosis (FSGS): can be primary or secondary, with secondary causes including viral injury, medication-related injury, or adaptive changes, as described in the 2023 study by 1
- Membranous nephropathy
- Membranoproliferative glomerulonephritis
Secondary Causes
- Diabetes mellitus: leading cause in adults
- Systemic lupus erythematosus
- Amyloidosis
- Infections: HIV, hepatitis B and C, malaria
- Medications: NSAIDs, gold, penicillamine
- Malignancies: particularly lymphomas and solid tumors
- Genetic disorders: congenital nephrotic syndrome
Pathophysiology and Treatment
The pathophysiology involves damage to podocytes and the glomerular basement membrane, leading to increased permeability and characteristic findings of heavy proteinuria, hypoalbuminemia, hyperlipidemia, and edema, as discussed in the 2007 study by 1. Treatment depends on identifying and addressing the underlying cause, with supportive measures including ACE inhibitors or ARBs to reduce proteinuria, diuretics for edema management, statins for hyperlipidemia, and immunosuppressive therapy for certain primary glomerular diseases, as recommended in the 2023 study by 1. Prompt diagnosis and management are essential to prevent complications like thromboembolism, infections, and progression to end-stage renal disease.
Recent Guidelines
The 2023 study by 1 provides guidance on the management of glomerular diseases, including the use of glucocorticoids and immunosuppressive therapy for patients with idiopathic immune complex glomerulonephritis. The 2023 study by 1 also proposes a novel classification system for FSGS, dividing patients into four subclasses: primary FSGS, genetic FSGS, secondary FSGS, and FSGS of undetermined cause.
Key Considerations
- Identifying and addressing the underlying cause of nephrotic syndrome is crucial for effective treatment, as noted in the 2014 study by 1
- Supportive measures, such as ACE inhibitors or ARBs, diuretics, and statins, can help manage symptoms and prevent complications, as discussed in the 2019 study by 1
- Immunosuppressive therapy may be necessary for certain primary glomerular diseases, but its use should be carefully considered due to potential side effects, as described in the 2014 study by 1
From the Research
Etiologies of Nephrotic Syndrome
The etiologies of nephrotic syndrome can be categorized into primary and secondary causes.
- Primary causes are diseases specific to the kidneys, while secondary causes are due to systemic disorders.
Primary Causes
Some of the primary causes of nephrotic syndrome include:
- Minimal change disease, which is the most common cause in children 2, 3, 4
- Membranous nephropathy, which is the most common cause in white adults 2, 3, 5
- Focal segmental glomerulosclerosis (FSGS), which is the most common cause in populations of African ancestry and also common in adults 2, 3, 4
Secondary Causes
Secondary causes of nephrotic syndrome include:
- Diabetic nephropathy, which is the most common multisystem disease that can cause nephrotic syndrome 2
- Systemic lupus erythematosus 2, 3, 5
- Amyloidosis 2, 3
- Hematologic malignancies 3
- Infections 3
Diagnosis and Evaluation
Diagnosis and evaluation of nephrotic syndrome involve documenting proteinuria and hypoalbuminemia, and assessing for secondary causes 2, 3, 5. A renal biopsy is often performed to establish the underlying glomerular disease responsible for the syndrome 2, 3, 5.