KIDNEY INVOLVEMENT IN SCLERODERMA

The kidneys are vital organs that have many life-sustaining functions. They may be involved in scleroderma and much progress has been made since kidney involvement in the disease was first described in the middle of the last century. Scleroderma has three principal elements; uncontrolled fibrosis, changes in the blood vessels and very characteristic antibodies, which are directed against normal components of the body. Fibrosis occurs when the normal processes involved in wound healing and scarring are overactive and is most obvious in scleroderma when it affects the skin. The flow of blood to different organs is highly regulated to meet their needs. Many factors are involved in the contraction and dilatation of the blood vessels that are necessary to control blood flow. Abnormal regulation of blood vessels is most commonly recognised in scleroderma when this occurs in the skin, producing Raynaud’s phenomenon. Fibrosis and changes in blood vessels may both involve the kidney and may have devastating consequences if they are not recognised early in their course.

A significant minority of patients (up to 15%) may develop an acute scleroderma crisis. This causes very high blood pressure and will cause kidney failure if not promptly treated. High blood pressure does not normally cause any symptoms. However, in scleroderma the rapid rise in blood pressure can cause headaches, changes in vision, confusion or disorientation and may even cause seizures. If any patients develop any of these features medical attention is urgently needed. If local doctors, who may be unused to dealing with this emergency, are not immediately available, we would recommend contacting the staff at the Royal Free to alert them to the degree of urgency these symptoms suggest. We recommend that patients at risk of this complication have their blood pressure monitored regularly so that timely introduction of drugs to lower the blood pressure can reduce the risks of damage to the kidneys. Equipment for measuring the blood pressure at home is commercially available but it is worth discussing which of the many products on the market are the most suitable before any purchase.

Old textbooks of medicine reflect the traditional belief that involvement of the kidney in scleroderma is associated with very poor outcomes. Although there is no room for complacency the treatment of kidney disease in scleroderma has been revolutionised in the last few years. An audit of the experience at the Royal Free has recently been completed. Patients with acute crises may still require dialysis despite improvements in treatment but good outcomes, no dialysis or temporary dialysis, were seen in well over half of the cases seen at the Free. These figures compare favourably with those seen at the largest centre treating scleroderma patients in North America.

The introduction of a class of drugs called ACE inhibitors has been responsible for much of the improvement. There are many drugs within this class. Captopril, enalapril, quinapril, lisinopril, perindopril are examples that are widely used. Kidney function does need to be monitored when the drugs are introduced and this may mean a series of blood tests in the weeks after starting therapy. These drugs have few side effects but occasionally patients will develop an irritating cough or allergic reactions. If a cough occurs changing to a different class of drug called an angiotensin receptor antagonist may alleviate this side effect.

Kidney involvement in scleroderma remains a serious problem. Increased awareness of the problem and developments in treatment have greatly improved the outcome. Much more work is required to understand this complication and further improve outcomes for patients.

Ed Kingdon

Clinical Research Fellow

Royal Free Campus

Royal Free University College Medical School

London.

Article written for The Scleroderma Society’s Autumn Newsletter ‘Scleroderma News’ in the UK.