Membranous nephritis is one of a group of conditions called ‘glomerulonephritis’, where the immune system damages the kidney. Nephropathy, nephritis or glomerulonephritis are all used, but they all mean the same.
The name of the condition refers to the appearances of a kidney biopsy under the microscope. The glomerulus, the filtering unit of the kidney, is about the size of a pinhead. It is made up of membranes, which are capillaries that filter the blood, and a supporting structure called the mesangium. In this condition the membrane is thickened, but the supporting structure (the mesangium) is normal.
Because membranous nephritis can only be diagnosed with certainty under the microscope, it is only diagnosed after a biopsy test of the kidney.
What are the symptoms of Membranous nephritis?
These are variable from case to case. In many cases there are no symptoms, but the damage to the glomeruli causes some protein to appear in the urine. In some cases the protein loss can be large enough to be associated with water retention, and swelling of the face, hands or feet. This is called nephrotic syndrome.
What causes Membranous nephritis?
Basically doctors do not know fully. The immune system causes some damage to the kidney. In some cases of membranous nephritis there is an identifiable cause for the immune stimulation, for example lupus, hepatitis, or a tumour somewhere in the body but more often the cause is not clear.
What will happen if I have Membranous nephritis?
The outcome is very variable, and you will need to ask your specialist how things are likely to be in your case. The possibilities are:-
- It may continue unchanged for many years, requiring either only regular check-ups, by a specialist treatment if there is nephritic syndrome. This is probably the case in 3 out of 5 people (60%) with membranous nephritis.
- It may go away on its own in some cases, and this occurs more often than in other types of glomerulonephritis. About 1 in 5 people (20%) may get better on their own.
- In some cases kidney failure develops, leading to the question of dialysis and/or transplantation. This may occur in about 1 in 5 people (20 %)
What are the complications of Membranous nephritis?
- High blood pressure may develop. This damages the kidneys and puts a strain on the heart and the rest of the circulation. Therefore high blood pressure should be treated vigorously.
- Kidney failure may sometimes occur. If so, it usually develops slowly, so you need not be concerned about a sudden change in your condition.
- There may be protein leakage from the kidneys. This may be slight and only detectable on urine tests, or occasionally there are high levels of protein leakage leading to swollen ankles and high levels of cholesterol in the blood. This is called nephrotic syndrome, and requires specialist assessment and treatment.
Is there any Treatment?
This is not an easy condition to treat, especially when some people may slowly get better without being given treatment. Everyone with membranous nephritis should have active treatment of their blood pressure, which benefits anyone with kidney disease. If the cholesterol is very high, treatment to reduce the levels may help. Some people may benefit from treatment that reduces the activity of the immune system. The value of drug treatment depends on many factors, and is best discussed on an individual basis. The drugs used include steroids, azathioprine, cyclosphosphamaide, or a drug more often used to treat blood conditions, called chlorambucil.
Can I lead a normal life with Membranous nephritis?
In most cases this condition does not affect normal life. There is no special diet that will make the disease go away or get worse, though if the blood pressure is high or there is water retention, salt should be restricted in the diet. Physical exercise and sports can be undertaken.
There will be some queries if you apply for mortgages or life insurance, so someone should plan ahead and be prepared to have the doctors asked to supply a medical report.
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.