Minimal change Nephropathy (in adults)
Minimal change Nephropathy (in adults)The combination of the kidneys leaking a lot of protein (see proteinuria) and the body retaining so much salt and water that there is swelling of the hands, face or ankles is called nephrotic syndrome. In adults, a biopsy test of the kidney is normally performed to see what the kidney looks like under the microscope, and minimal change is one of the commonest causes of nephrotic syndrome. In children, nephrotic syndrome is nearly always caused by minimal change, and a biopsy may not be performed unless drug treatment fails to work.
The usual symptom is ankle swelling, or swelling of the face and hands. This may come on quite suddenly, and may vary with the time of day. Problems such as heart disease can also cause salt and water retention, and a urine test for protein is required to confirm whether the kidneys are causing this. Normally minimal change nephropath is quite painless, although swelling in the legs and around the abdomen can be uncomfortable. In severe cases there may be breathlessness because of fluid around the lungs - this needs to be treated urgently.
Basically no-one knows fully. It is called minimal change because the kidney looks pretty well normal under the microscope. When blood passes through the kidneys, it is filtered to produce the urine. The membrane that performs the filtration process is a very delicate structure. A slight abnormality in the structure can cause protein molecules to appear in the urine, though they are normally too small to get through. Although the membrane looks normal under the microscope, there may be a slight change in the electrical charge which causes this protein leakage. Many patients with minimal change have mild allergic conditions such as eczema, but it has not been possible to show that minimal change itself is an allergy.
Minimal change causes fluid retention in various parts of the body, often with high blood pressure. Normally doctors can treat minimal change with drugs and get a cure, or at least control of the condition. The main function of the kidneys is to remove waste products from the blood. This is not affected. Therefore minimal change does not cause kidney failure (except temporarily in very rare cases).
This condition is normally treatable with drugs.
While someone has salt and water retention, the amount of water and other liquids consumed each day should be reduced, and the medical team will advise on the best level for each person. Salt should be reduced as much as possible, not adding it to cooking, and avoiding any pre-prepared food containing salt. Diuretic tablets may be used. These are drugs which force the kidneys to produce more urine, and are also called ‘water tablets’.
Minimal change can normally be reversed with drugs.
The best drug to use in treatment is prednisolone (a steroid). A course of high dosage for 2-4 weeks generally results in disappearance of the protein in the urine and of the swelling. The prednisolone dosage is then gradually reduced and eventually stopped in many cases. Unfortunately some patients get side effects from the steroids. These include appetite increase and weight gain, change in the shape of the face and a tendency to be more prone to infection.
When the steroid dosage is reduced, the condition sometimes relapses (comes back). This may be obvious, with more swelling. Alternatively, many of our patients test their own urine at home for protein and so can tell if there is a relapse. A relapse may mean that more steroids should be given, and advice should be obtained urgently from the kidney specialist.
If steroids do not work, or only prevent relapses at high dosage, more powerful drugs are available. The specialist may use cyclosporin or cyclophosphamide. These have a range of other side effects, but are generally effective. A drug called levamisole is occasionally used, especially in children if makes it possible to avoid more powerful drugs such as cyclophosphamide. The options for treatment vary with each case, and should be discussed with the specialist.
In some cases, if fluid retention is severe, a period of time in hospital is necessary. Blood clots can be a complication of severe nephrotic syndrome, and blood thinning treatment may be given with injections, or in the longer term with warfarin tablets.
Click here to go to the Drugs index page, then link to pages on prednisolone, cyclosporin, cyclophosphamide and diuretics.
It may be necessary to rest and have time off work when the condition is acute. However, in the long term you should be able to lead a normal life when the condition is under control.
There may be some queries if you apply for mortgages or life insurance, so plan ahead and be prepared to have your doctors asked to supply a medical report.
Adapted from a leaflet written by Rob Higgins, Renal Consultant, Walsgrave Hospital, Coventry, 1998.
NKF Controlled Document No. 6, Minimal change Nephropathy (in adults), written 1 August 2000. Last reviewed 5 November 2008.
The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.
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Page created: 1 August 2000
Last updated: 29 April 2009
What is Minimal Change Nephropathy?