Vasculitis is an inflammation of the blood vessels. It happens when the body’s immune system attacks the blood vessel by mistake. It can happen because of an infection, a medicine, or another disease, but often the cause is unknown.
The term angiitis is synonymous with the term vasculitis - they mean the same thing - while the term arteritis is used to specifically refer to an “inflammation of the arteries”. The group of disorders broadly classified as vasculitis conditions are known collectively as vasculitides (pronounced vas.que.lit.eye.deez).
The vasculitides are a group of autoimmune inflammatory diseases where the body’s own immune system attacks either the lining (endothelium) or the walls (mural structures) of arteries, veins or capillaries. The swelling caused by inflammatory processes can lead to a reduction in blood flow (ischemia), or to a complete obstruction of the blood supply to a region of tissue or an organ (an infarction), depriving the tissue or organ of vital oxygen, which may in turn result in areas of tissue death (necrosis) in some or all of an organ. Inflammatory damage may also weaken blood vessel walls, causing abnormal dilations (aneurysms), which may in turn rupture, resulting in bleeding through the vessel wall (haemorrhaging).
The vasculitides are therefore serious and sometimes fatal conditions requiring prompt recognition and therapy. Unfortunately vasculitis conditions are often difficult to classify, describe and diagnose: First, they are rare diseases, with prevalence rates measured in individuals per hundred thousand - or even million - so doctors in general practice are not usually experienced or familiar with them; second they may affect virtually any or all organs in the body - including the skin, lymph vessels, muscles, nerves, the brain, the heart, lungs, stomach and kidneys - so they may present an often bewildering array of symptoms; third, they are often idiopathic (their cause is often unknown), so doctors don’t have a firm causal chain of evidence to trace back to aid diagnosis; fourth, their pathologies often overlap with other disease processes and their symptoms are often non-specific, suggesting a range of alternative, more common and possibly unrelated syndromes – including stress, depression, or even hypochondria – anecdotally at least, misdiagnosis and treatment is therefore common.
The vasculitides are particularly unpleasant diseases to contract, not only because of their destructive and sometimes fatal systemic effects, but also because their treatment often involves medications that have significant adverse side-effects and that often need to be administered over lengthy periods of time, usually to affect a remission rather than a cure.
The good news is that caught early, correct medication utilising corticosteroid anti-inflammatories (to reduce swelling) in conjunction with cytotoxic agents (to dampen the immune reaction) in most cases will lead to a remission.
None of the vasculitides are known to be contagious.
The vasculitides have traditionally been classified by their broad pattern of clinical features, such as vessel size (large, medium or small) or type of vessel involvement (artery, vein or capillary), by their histopathological features (changes in tissues caused by the disease) or by the character of the inflammatory infiltrate (the type of immune cell active or present at the site of inflammation - for example neutrophils, leukocytes or monocytes). Recent advances in the understanding of immunopathogenic mechanisms (such as antineutrophil cytoplasmic antibodies [ANCA]) may offer additional classification and diagnostic tools.
Broadly however the vasculitides may be separated into primary vasculitis conditions and secondary vasculitis conditions. Historically the primary vasculitides have been described as being idiopathic; that is as having an unknown cause or as arising “out of the blue”, however this characterisation is misleading; causal elements and mechanisms have been postulated and found for some primary vasculitides (e.g. Buerger’s disease has been linked with smoking). The primary vasculitides are therefore best characterised as diseases in their own right, with no defined preceding or accompanying disease, while secondary vasculitides are vasculitis conditions secondary to, or associated with, an underlying disease process. Secondary vasculitis is also the term employed when the underlying cause is a neoplasia, drug, or other toxin.
Thirteen primary vasculitis conditions are recognised. They are:
Note: Primary vasculitides are inclusive of systemic vasculitides, simply meaning the vasculitis condition may express itself anywhere in the body, also of the term idiopathic vasculitis, a vasculitis condition arising from an unknown cause (as distinct from having “no cause”).
Secondary vasculitides do have known causes. For example:
Secondary vasculitides may also be noted in association with other diseases and syndromes. For example:
Common descriptive terms utilised in reference to both primary and secondary vasculitides include:
Vasculitis conditions may then be described using more than one of the above terms. For example Churg-Strauss syndrome is a medium sized vessel vasculitis as well as being both a granulomatous and an eosinophylic vasculitis condition.
Dirk Biddle, December 2013
1. Scott, R. (2000) Vasculitis. Professor David Scott, of the Norfolk and Norwich Hospital, explains the various diseases classed as vasculitis, and highlights ever-improving treatments (http://www.arc.org.uk/newsviews/arctdy/107/vasc.htm).
2. Jennette, J., Falk, R., Andrassy, K., Bacon, P., Churg, J., Gross, W., Hagen, E., Hoffman, G., Hunder, G., Kallenberg, C., et al. (1994) Nomenclature of systemic vasculitides. Proposal of an international consensus conference. Arthritis Rheumatica, 37(2), 187-92.
3. American College of Rheumatology: Classification criteria (http://www.rheumatology.org/publications/classification/index.asp?aud=mem).
4. Buckingham, E., Bailey, B., Quinn, F. (2000) Connective Tissue Diseases: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology (http://www.otohns.net/default.asp?id=4160).
5. Matteson, E. (2005) A Puzzler among Rheumatic Diseases. American College of Rheumatology (http://www.rheumatology.org/public/usatoday/vasculitis.asp).
6. Rao, J., Allen, N, Pincus, T. (1998) Limitations of the 1990 American College of Rheumatology classification criteria in the diagnosis of vasculitis. Annuls of Internal Medicine, 129(5), 345-52.
7. Johns Hopkins Vasculitis Center. (1998) What is Vasculitis? (http://vasculitis.med.jhu.edu/whatis/symptoms.html).