From the Guidelines
Nephrotic syndrome is characterized by proteinuria > 3.5 g/d AND serum albumin <30 g/l with or without edema. This definition is based on the most recent guideline for the management of glomerular diseases, which emphasizes the importance of both significant proteinuria and hypoalbuminemia in the diagnosis of nephrotic syndrome 1. The key features of nephrotic syndrome include:
- Massive proteinuria, with protein excretion exceeding 3.5 grams per day
- Hypoalbuminemia, with serum albumin levels less than 30 grams per liter
- Edema, which can be present in various parts of the body, including the lower extremities, periorbital area, and abdomen
- Hyperlipidemia, resulting from the liver's increased production of lipoproteins in response to low albumin levels
According to the KDIGO 2021 guideline, the presence of nephrotic syndrome is determined by the combination of proteinuria and serum albumin levels, rather than just proteinuria alone 1. This guideline provides a clear framework for evaluating patients with suspected nephrotic syndrome and highlights the importance of excluding secondary forms of focal segmental glomerulosclerosis (FSGS) and evaluating for underlying causes. The clinical presentation of nephrotic syndrome can vary, but the hallmark feature is the excessive leakage of protein from the blood into the urine, leading to a range of complications, including edema, hyperlipidemia, and increased risk of thromboembolism.
From the FDA Drug Label
To induce a diuresis or remission of proteinuria in the nephrotic syndrome, without uremia, of the idiopathic type or that due to lupus erythematosus
- Nephrotic syndrome is characterized by proteinuria.
- The condition may be idiopathic or due to lupus erythematosus.
- It is also associated with edema (edematous states) 2.
From the Research
Characteristics of Nephrotic Syndrome
- Nephrotic syndrome is characterized by edema, proteinuria, hypoalbuminemia, and hyperlipidemia 3, 4, 5, 6, 7
- The syndrome occurs due to increased permeability to proteins at the level of the glomerulus, allowing for passage of albumin and other proteins into the urine 4
- Proteinuria leads to a cascade of clinical complications, including fluid accumulation, kidney inflammation, and dysregulation of coagulation and immunity 4
Clinical Features
- Patients with nephrotic syndrome typically present with edema and fatigue, without evidence of heart failure or severe liver disease 5, 6
- The diagnosis of nephrotic syndrome is based on typical clinical features, with confirmation of heavy proteinuria and hypoalbuminemia 5, 6
Complications
- Important complications of nephrotic syndrome include venous thrombosis and hyperlipidemia 5, 6
- Other potential complications include infection, acute kidney injury, and neurologic manifestations resulting from hypoproteinemia, hypercoagulability, hyperlipidemia, hypertension, amyloid deposition, hormonal changes, or electrolyte disorders 5, 6, 7