Triad of hypoalbuminemia, peripheral edema, hyperlipidemis, and proteinuria.
Rare process within incidence of three per 100,000 person-years in adults
Causes in adults include systemic diseases: SLE, diabetes, hepatitis b, hepatitis C, HIV, cancer, sickle cell anemia, amyloidosis, light chain disease, heavy chain disease, malaria, schistosomiasis, syphilis: and renal diseases: glomerulosclerosis-primary focal and segmental, secondary focal and segmental, membranous glomerulonephropathy, membranoproliferative glomerulonephritis, IgA nephropathy, minimal change disease and fibrillary and immunotactoid glomerlopathies.
Primary causes: focal segmental glomerulosclerosis, membranous nephropathy, minimal change disease and membranoproliferative nephropathy.
Secondary causes: congenital, systemic disease, malignancy, infections, and drugs.
It is a marker of occult solid tumors and hematologic malignancies, and is associated with a worsening malignant prognosis.
Congenital causes: Alport’s syndrome, congenital syndrome of the Finnish type, Pierson’s syndrome, Nail-Patella syndrome, Denys-Drash syndrome.
Systemic causes: Diabetes , SLE, Amyloidosis
Cancer causes: myeloma and lymphoma
Infection causes: HIV, Hepatitis B and C, Mycoplasma, Syphilis, Malaria, Schistosomiasis, Filariasis, Toxoplasmosis
Drug causes: Antimicrobial agents, Captopril, antiVEGF monoclonal antibodies, Lithium, Penicillamine and Tamoxifen.
Membranous glomerulonephritis is the most common cause in white adults.
Focal segmental glomerulosclerosis becoming increasingly recognized, particularly in black patients, in whom it is the underlying etiology in more than half the cases.
Associated with more than 3.5 gm per day of protein in the urine.
Nephrotic syndrome in children is defined as proteinuria of greater than 1 g of urine protein per square meter of body surface area per day, albumin level of less than 2.5 g, cholesterol total of greater than 200 mg/dL and edema.
Nephrotic syndrome in adults defined is a urine protein level of more than 3.5 g per day, albumin level less than 3.5 g/dL.
Can occur in infants, children and adults.
Affect all races and ethnic groups.
Some patients at risk for end-stage renal disease.
Early diagnosis and treatment may prevent progression of disease and loss of kidney function.
Early in syndrome kidney function is normal, but patients with proteinuria have a high risk of loss of kidney function.
If the liver fails to fully compensate for urine losses of albumin, hypoproteinemia can occur with decreased plasma oncotic pressure and loss of intravascular fluid into the interstitium.
A few processes associated with nephrotic syndrome are consistently associated with increased risk of venous thromboembolism: membranous nephropathy membranoproliferative glomerulonephritis, minimal change disease and perhaps renal amyloidosis.
Sodium and water retention may occur and patients may have frothy urine, eruptive xanthomas or xanthelasmata.
Symptoms usually result from edema.
May be associated with renal vein thrombosis.
Thromboembolism in patients with nephrotic syndrome can arise from increased platelet activation and aggregation, loss of anticoagulant proteins, decreased fibrinolytic system activity and associated problems such as the antiphospholipid syndrome.
The annual incidence of venous thromboembolism is approximately 1% in the nephrotic syndrome.
The risk of thromboembolism in the nephrotic syndrome is more closely linked with hypoalbuminemia then to proteinuria.
In the nephrotic syndrome the risk of venous thromboembolism increases by a factor of 2 for each decrease of 1gm per d/L in the albumin level.
The incidence of renal vein thrombosis ranges from 6-62% , with an overall incidence of 35% (Llach).