Vasculitis: Inflamed Vessels

Blood vessels run throughout the body – from the large aorta, to the tiny capillaries in the tissues, to the veins that carry blood back to the heart. It is easy to imagine that vascular changes can lead to a variety of disorders in different organs. One such change is vasculitis, an inflammation of the blood vessels. What is behind it and what forms are there? You can find out here.

What is vasculitis?

Vasculitis (plural: vasculitides) is a term that encompasses numerous quite different, fortunately rare, clinical pictures that have one thing in common: Inflammatory changes occur in blood vessels. Vasculitis is thus a collective term for various forms of vascular inflammation. Since it is a rheumatic inflammation, it is also referred to as blood vessel rheumatism. Almost all vasculitides belong to the autoimmune diseases, i.e. they are triggered by misdirected reactions of the immune system against the body’s own tissue and are also referred to as immune vasculitis. Rarely, inflammation can also result from infection of the vessels, for example, by bacteria or fungi.

Vasculitis: what is happening in the body?

In vasculitis, the vessel wall of one or more blood vessels becomes inflamed. The swelling that occurs causes the affected vessel to become narrower and less blood to pass through it – this narrowing is called stenosis. As a result, organs and tissues are no longer supplied with sufficient oxygen and their function is impaired. If the blood vessel closes completely, tissue death or a life-threatening organ infarction can occur. In addition to the swelling of the vessel walls, possible consequences of vasculitis include the vessel walls becoming permeable to blood components or bursting. Outpouchings (aneurysms) can also form, which can lead to bleeding.

What are the different forms of vasculitis?

In principle, experts distinguish primary forms, which directly affect the vessels, and secondary forms, in which the vessels are affected in the context of other diseases (for example, collagenoses, AIDS) or react to certain drugs. Because symptoms depend primarily on which blood vessels are affected (and to what extent), the primary forms have been further classified accordingly since 1992, and the individual clinical pictures (some with complicated names) have been sorted under them:

  • Small vessel vasculitis:
  • Vasculitis of medium-sized vessels:
    • Panarteritis nodosa (cPAN, also: polyarteritis nodosa, PAN).
    • Kawasaki syndrome
  • Large vessel vasculitis (giant cell arteritis, RZA):
    • Giant cell temporal arteritis (under which the two diseases polymyalgia rheumatica and temporal arteritis Horton are grouped).
    • Takayasu arteritis
  • Vasculitis of variable vessel size:
    • Cogan I syndrome
    • Behçet’s disease

In addition, there are other classification criteria, for example, there are vasculitis of individual organs. These include skin vasculitis (cutaneous leukocytoclastic vasculitis) and primary angiitis of the central nervous system (CNS). There are also variants of vasculitis that can occur in the setting of several of the aforementioned forms, such as cerebral vasculitis. Behind all these different forms of vasculitis lie their own clinical pictures, each of which causes different symptoms and requires correspondingly different forms of treatment.

Necrotizing vasculitis and Raynaud’s syndrome.

If the inflammation leads to destruction of the vessel walls and occlusion of the blood vessels with death (necrosis) of the surrounding tissue, it is called necrotizing vasculitis. It occurs mainly in ANCA vasculitis of the small vessels and in panarteritis nodosa, and the course and prognosis tend to be worse than in the other forms. Vasculitis can also lead to vascular spasms, especially in cold conditions, secondary Raynaud’s syndrome. Consequences are whitening or blueness of the fingers, fingertips or the whole hand. This often occurs in smokers who suffer from thrombangiitis obliterans (Winiwarter-Buerger syndrome), an inflammation that takes place in individual sections of blood vessels, where it leads to blood clots with vascular occlusion.

How does vasculitis develop and who is affected?

The exact causes of vasculitis are still unknown. It is likely that external factors such as infection with viruses (for example, influenza or viral hepatitis) play a role, triggering the immune responses and subsequent inflammation in people with a certain genetic susceptibility (i.e., a corresponding genetic predisposition). Interestingly, many of the diseases play out predominantly in certain groups of people – for example:

  • Kawasaki syndrome and Schönlein-Henoch purpura in childhood.
  • Takayasu’s arteritis in younger women.
  • The polyarteritis in middle-aged men
  • The giant cell temporal arteritis in the elderly