Lupus: How does it affect the kidneys?
Written by:Lupus is an autoimmune condition whereby the immune system starts to attack your own body instead of just fighting off the infection. It can affect almost any part of your body and is more likely to occur in women of childbearing age, particularly in African and Asian women.
The more serious complications of lupus can affect the kidneys, which is known as lupus nephritis. Approximately 70 to 80 per cent of people with lupus develop this condition. Here, one of London’s top nephrologists Professor Liz Lightstone explains just how lupus affects the kidneys and the ways in which it can be diagnosed and managed.
What are the symptoms of lupus?
The most common symptoms include:
- A rash on your face
- Sun sensitivity
- Joint pain, in the small joints of the hands and feet which is worse in morning
- Hair loss in patches or in large amounts in some people
- In some cases, there can be pain when breathing
- Feeling overwhelmingly tired, which is not often realised to be part of something bigger
How might lupus affect the kidneys?
Lupus can affect the kidneys in several ways. Most people are unaware of this and we therefore need to test the urine for the presence of protein (proteinuria) that shouldn’t be there. We also test the blood for abnormal kidney function.
The most common finding is protein in the urine, which is due to leakiness in the kidney caused by inflammation. If the protein in the urine is very high, in order of several grams a day, it can lead to a drop of protein levels in your blood.
It causes you to develop swelling in your ankles and legs when standing and moving, as well as developing a puffy face. Inflammation of the kidneys is generally called lupus nephritis and in different patients we have specific ways of diagnosing it depending on the individual’s symptoms.
What tests are used to diagnose lupus nephritis?
It is really important that people with lupus have their blood pressure checked, urine dipped and kidney function measured regularly. Lupus nephritis can be entirely without symptoms and it is really important to detect as early as possible.
If we dip the urine in patients with lupus, we can often detect invisible blood, which is what we call micro blood in the urine or microhaematuria. Testing urine can be a problem in women due to their menstrual cycle and therefore we tend to see them every four weeks otherwise it is impossible to test when they have their period.
When we are making our diagnosis, we look at kidney function, what’s in the urine and the degree of proteinuria, whether there are new onset changes or if the proteinuria is rising.
We would recommend a kidney biopsy to make a diagnosis. This is done under local anaesthetic and is a very quick procedure. We do this so the we can examine a tiny piece of kidney under a microscope and check for inflammation.
What are the treatment options?
We classify lupus nephritis according to international recommendation and there is specific treatment advised for what are called classes III, IV and V.
The standard treatment of lupus nephritis includes corticosteroids and a more potent immunosuppressant such as mycophenolate mofetil (MMF) which is given in tablet form, or cyclophosphamide which is given intravenously with a drip in the vein.
Your specialist will discuss the best form of treatment given the biopsy findings and kidney function. There are side effects with these medications and the aim is to minimise these and to optimise your treatment.
I have currently been pioneering newer alternative treatments that minimise the use of steroids with a drug called Rituxan. It is quite exciting that it’s been positively trialled in the last few months. It contains newer agents that look promising in reducing toxicity and reducing steroids.
If you’re living with lupus and would like to be tested for lupus nephritis, do not hesitate to book an appointment with Professor Lightstone via her Top Doctor’s profile here.
