What Is Nephrotic Syndrome?
Nephrotic syndrome is a kidney disorder. It causes large amounts of protein to show in the urine. Losing protein in the urine makes the level in the blood low. Normally the blood protein keeps water in the blood and stops it from leaking out into the tissues.
When you have Nephrotic Syndrome the low levels of protein in the blood lets the water leak into the tissues which makes them become swollen. The swelling of the body tissues is called oedema. All of the body tissues swell, but mostly the stomach, legs, face, penis and the scrotum.
Causes of Nephrotic Syndrome
The cause is unknown. It commonly occurs in 2-3 year old children but all ages can be affected. Many children who are affected have illnesses caused by allergy (e.g. asthma, eczema and hay fever), but no particular allergic factor has been identified in children with Nephrotic Syndrome. Like other allergic diseases, Nephrotic Syndrome responds to drugs called steroids. It most commonly occurs in spring time.
A cortisone-like steroid drug called prednisone is given to children with nephrotic syndrome. In 90% of children, it causes a complete remission of the condition, and the protein in the urine and the oedema disappears. Large doses are needed to be given for a few weeks to produce this remission. These large doses are generally well tolerated with no side effects apart from slight roundness of the face. The dose is rapidly reduced after remission occurs.
In addition most patients are given penicillin to prevent infection and also aspirin to prevent blood clotting. This is because nephrotic patients are prone to infection and clotting while oedematous but not after remission.
What Are The Signs That Remission Is Occurring
There is a sudden complete clearing of protein in the urine over 1 or 2 days. The child passes large amounts of urine during remission and loses all the oedema.
When Does Remission Occur?
Usually this happens in the second week after starting the high doses of prednisone. There are generally no signs of improvement after starting the prednisone until the day of remission. While waiting for prednisone to produce remission many patients get more swollen because of the continuing proteinuria.
After Remission What Happens?
Nephrotic children in remission have no signs of disease. The dose of prednisone is gradually decreased over the next 2-3 months.
You will also be asked to test your childs urine each morning to detect any proteinuria which could indicate a relapse of the nephrotic syndrome. It is easy and involves dipping a plastic test strip called albustix in the first specimen passed each morning. The Albustix remains yellow if there is no proteinuria but goes green if protein is present
What Is A Relapse Of Nephrotic Syndrome?
This is shown by a reappearance of heavy proteinuria (green albustix) for at least 7 days. If not treated, oedema appears later. By testing every day, relapses may be detected before oedema develops.
Many normal children, and also children with Nephrotic Syndrome develop proteinuria for 2-5 days during a cold or any feverish illness. In normal children this proteinuria clears within a week.
In Nephrotic Syndrome the proteinuria lasts longer than a week and indicates that a relapse is occurring. Many relapses appear to start with a cold, the proteinuria persisting after the cold has passed.
Relapses occur in 75% of children with Nephrotic Syndrome, particularly in the first 2 years. Relapses become less frequent as the child gets older and are rare in adulthood. Relapses can occur after the prednisone dose is lowered or the treatment has been stopped. Relapse rarely occurs on high doses.
Treatment For A Relapse
Prednisone is given again in high doses and most relapses can be cleared before too much oedema develops. Early treatment means that most relapses are minor and very few require hospitalisation.
Side Effects Of Prednisone
Appetite can be stimulated. Any doctor who treats your child should be told that they are taking prednisone, as many illness will be treated differently if the patient is on cortisone-like drugs.
Treatment must never be stopped suddenly as steroid drugs replace the bodies own cortisone production by the adrenal glands, and this may take some time to recover after been on steroids.
If your child has any serious illness or requires an anaesthetic within 2 years of receiving prednisone, further steroid therapy may be required, as the adrenal glands may be unable to provide the extra cortisone needed to cope with the stress of the illness. Frequent high doses may stunt growth over a long period of use. It may cause roundness of the face or obesity.
If your child does not respond to prednisone they may use cylophosphamide. It prevents relapses of Nephrotic Syndrome. However, possible side effects are more severe than for prednisone, and it is only used when frequent relapses of Nephrotic Syndrome occur.
Cyclophosphamide tends to lower the number of white cells in the blood. These cells are involved in resistance to infection. It occasionally causes a mild hair loss, but patients do not lose sufficient hair for it to be noticeable.
Because of its side effects cylophosphamide is not given to children with Nephrotic Syndrome unless frequent relapses occur and the patient is at risk of prednisone side effects, particularly the stunting of growth. It is a very effective drug for these patients.
Are There Other Treatments For Nephrotic Syndrome
No other drugs or medications are currently used in NZ to help Nephrotic Syndrome.
Special diets are not useful in producing remission or preventing relapse. During relapses salty foods should be avoided as salt aggravates the oedema. High protein diets are not tolerated by children who are nephrotic and should be avoided.
If gross oedema occurs, some children need protein given by a drip into a vein. This is likely to be needed if more than 3-4 kg weight gain occurs during relapses, or if oedema of the penis or scrotum occurs or if the patient develops cold hands or feet due to poor circulation. Protein infusion causes reduction of oedema, but does not affect the proteinuria which must be cleared with prednisone. Protein infusion often needs repeating each day until remission occurs.
Outlook For Nephrotic Syndrome Children
Most children have relapses for a few years but these become fewer as the child gets older. It is rare in adulthood to have a relapse of Nephrotic Syndrome. Between relapses the child should be fit and well and should led a normal life. Provided relapses are picked up early by albustix testing, most relapses can be treated at home. The long term outlook for prednisone responsive Nephrotic Syndrome children is excellent and such children grow up to become normal adults
Unusual Variety Of Nephrotic Syndrome
A small number of nephrotic children have unusual features such as blood in the urine or high blood pressure. Some do not have the typical remission of proteinuria when given prednisone. Such cases may need other treatments and have a different outlook and a different course of treatment. The course of the disease can only be detected by a kidney biopsy. This involves taking a small piece of the kidney through a needle for examination under a microscope.
Kidney biopsy is generally not needed in management of the typical case of Nephrotic Syndrome.
This advice is only intended to be a guideline and is very general. Please check with your specialist or GP if you have any questions relating to your child’s condition.