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Vasculitis
Vasculitis
These are sometimes serious chronic diseases that affect men and women and, much more rarely, children or adolescents. However, certain age groups are more commonly (or even exclusively) affected, depending on the type of vasculitis diagnosed (for example, giant cell arteritis, or “Horton’s disease”, which occurs only after the age of 50).
Vasculitis (called vascularites in France) is defined by the presence of inflammation of the blood vessels: arteries, veins and/or capillaries.
The walls of the affected vessels may either thicken or, more rarely, become thinner and dilate. If blood flow through the affected vessels is severely reduced or stops altogether (thrombosis – the formation of blood clots), the organs or tissues supplied by these vessels no longer receive sufficient oxygen and become dysfunctional or damaged, potentially progressing to necrosis (i.e. cell death) of the affected organ or tissue.
The origin of these diseases is complex and still relatively poorly understood. The main factors are environmental (such as infection with certain viruses) and/or intrinsic to the patient’s immune system, which—in addition to defending against external agents (such as microbes)—attacks and damages the individual’s organs (the concept of autoimmunity). This predisposition to immune-system dysregulation is thought to have a genetic origin, although we still know very little about the genetic abnormalities involved. Fortunately, this genetic influence does not imply a significant risk of familial transmission.
The term vasculitis encompasses a range of different diseases that share inflammatory involvement of the blood vessels. These diseases are classified according to the size of the vessels affected by the inflammation: small-, medium- or large-vessel vasculitis.
- Among small-vessel vasculitides, a further distinction is made between those associated or not associated with the presence in the blood of an autoantibody called ANCA (for “Anti-Neutrophil-Cytoplasmic-Antibody”), an antibody directed against proteins expressed in neutrophils (the most abundant white blood cells in the blood). Small-vessel vasculitides include granulomatosis with polyangiitis (formerly Wegener’s disease), eosinophilic granulomatosis with polyangiitis (formerly Churg–Strauss syndrome), microscopic polyangiitis, IgA vasculitis and cryoglobulinaemic vasculitis (the latter two are not associated with ANCA).
- Medium-vessel vasculitides include polyarteritis nodosa and Kawasaki disease (which affects almost exclusively children).
- Large-vessel vasculitides include giant cell arteritis (also called Horton’s disease) and Takayasu disease.
- Behçet’s disease involves vessels of several different sizes.
Clinical presentation
The clinical presentation of vasculitides varies considerably. Given the diversity of the type (for example, large or small blood vessels) and location of the vessels affected, depending on the disease, it is not possible to provide an exhaustive description here of the highly variable clinical presentations from one individual to another.
By way of example, the following are some of the ways in which certain vasculitides may present in their most typical forms:
- Horton’s arteritis - headaches, visual disturbances, pain in the shoulders and pelvis
- Granulomatosis with polyangiitis - fever, weight loss, diffuse joint pain, cough, shortness of breath, coughing up blood, nosebleeds, inflammation of the sinuses with hearing problems, kidney dysfunction
- Eosinophilic granulomatosis with polyangiitis - increasingly severe asthma, shortness of breath, cough, loss of strength and/or sensation in a nerve distribution (for example, in a foot or hand), red/purple spots on the skin.
Diagnosis
Diagnostic methods naturally include investigations directed at the affected organ or organs, as well as the search for specific findings that can establish a precise diagnosis. A key step is often performing biopsies of organs affected by the disease, which are analysed under a microscope by a specialist physician (anatomical pathologist) to look for vascular inflammation (vasculitis).
Other investigations are often required, such as vascular imaging (Doppler ultrasound, CT scan, PET-CT, etc.) in large-vessel vasculitides (such as giant cell arteritis, or “Horton’s disease”), or testing for antibodies directed against certain components of our body (for example, testing for ANCA in granulomatosis with polyangiitis).
Treatment
The aim of the treatment of vasculitides is to reduce immune-system activity. The cornerstone is a corticosteroid (commonly called “cortisone”), which is often rapidly effective but has a “bad reputation” because of its well-known side effects; these should be put into perspective according to the cumulative dose. Immunosuppressive medicines targeting a type of white blood cell—the lymphocytes—which are particularly involved in (auto)immunity, are also routinely added to some extent.
More recently, targeted treatments (called monoclonal antibodies) have proved to be major advances in the treatment of vasculitides. They are directed more specifically against certain lymphocytes or against molecules involved in inflammation/immunity. Access to them is limited by their very high cost and the reimbursement conditions set by INAMI. Sometimes, they are available only through clinical studies conducted in a limited number of hospitals.
Useful links
The French patient association
CANVASC (Canadian study group)
There is no Belgian patient association, but there is a Belgian contact person for the French association, whose contact details can be obtained from that French association.