is a disorder where the
Kidney s have been damaged, causing them to leak
Protein from the
Blood into the
Urine . It is a fairly benign disease when it occurs in childhood, but may lead on to
Chronic Renal Failure , especially in adults, or be a sign of an underlying serious disease such as
Systemic Lupus Erythematosus or a
Malignancy .
High urine levels of
Protein can readily be detected with a
Dipstick . The best way to make a diagnosis is to quantify the amount of protein in a 24-hour urine sample or a random albumin to creatinine ratio (ACR). A diagnosis of nephrotic syndrome requires more than 3.5 grams of proteinuria per 1.73 square meter surface area in adults. It is important to note, however, that nephrotic syndrome can be associated with lesser degrees of proteinuria, and many of the complications of nephrotic syndrome are due to hypoalbuminemia and the resultant decreased plasma
Oncotic Pressure . Therefore, the same consequences can result independently of the level of proteinuria, as long as the same degree of hypoalbuminemia is achieved.
Once the diagnosis of nephrotic syndrome is reached, further investigations must focus on the underlying disease process.
The
Glomeruli of the kidneys are the parts that normally filter the blood. They consist of
Capillaries that are fenestrated (leaky, due to little holes called ''fenestrae'' or windows) and that allow fluid, salts, and other small solutes to flow through, but normally not proteins.
In nephrotic syndrome, the glomeruli become damaged due to
Diabetes ,
Glomerulonephritis , or even prolonged
Hypertension (high blood pressure) so that small proteins, such as
Albumin can pass through the kidneys into urine.
Nephrotic syndrome is characterised by proteinuria (detectable protein in the urine), and low albumin levels in
Blood Plasma . As a compensation, the liver begins to make more of all its proteins, and levels of large proteins (such as
Alpha 2-macroglobulin ) increase.
Edema usually occurs due to salt and water retention by the diseased kidneys as well as sometimes due to the reduced colloid
Oncotic Pressure (because of reduced albumin in the plasma).
Cholesterol levels are also increased, and though the mechanism isn't fully understood, it is thought to be due to the increased synthesis of
Lipoproteins in the liver. There is an increased tendency for
Thrombosis (up to 25%), perhaps due to urinary loss of inhibitors of clotting such as
Antithrombin III .
Similar loss of
Immunoglobulins increases the risks of infections and relevant immunisation is recommended against
Pneumococcus ,
Haemophilus Influenzae , and
Meningococcus .
Primary renal diseases
Secondary renal diseases
- Genetic disorders: Alport Syndrome , Congenital Nephrotic Syndrome , Sickle Cell Disease
- Metabolic diseases: Diabetes Mellitus is the most common cause of secondary nephrotic syndrome in adults in developing countriesamyloidosis; Amyloidosis
- Autoimmune diseases: Systemic Lupus Erythematosus , Henoch-Schonlein Purpura , vasculitides
- Malignant diseases: , Colon , Breast , and Stomach ; Leukemia , Lymphoma
- Infectious diseases
- --- Bacterial: Infectious Endocarditis
- --- Viral: Human Immunodeficiency Virus , Hepatitis B , Hepatitis C
- --- Protozoal: Malaria
- --- Helminthic: Schistosomiasis
Others
When treating nephrotic syndrome, if the underlying problem is apparent, (e.g.
Hypertension ,
Diabetes ) then this should be addressed.
Some types of nephrotic syndrome respond to therapy with
Steroid s (especially
Minimal Change Disease ) and/or other
Immunosuppressive Therapy . Others are followed up in clinic with management of
Blood Pressure ,
Cholesterol levels,
Coagulation problems and
Renal Failure .
In most types of nephrotic syndrome, the protein excretion improves with the use of
ACE Inhibitor medication. This is generally used for the treatment of
Hypertension , but can also improve
Protein loss, even if the blood pressure is normal.
The prognosis depends on the cause of nephrotic syndrome. It is usually good in children, because
Minimal Change Disease responds very well to
Steroids and does not cause
Chronic Renal Failure . However other causes such as
Focal Segmental Glomerulosclerosis frequently lead to
End Stage Renal Disease . Factors associated with a poorer prognosis in these cases include level of
Proteinuria ,
Blood Pressure control and kidney function (
GFR ).
