Many vasculitides are
caused by a malfunctioning immune systems
Causes may be
unknown but vasculitides are thought to often be the result of the
combinations of:
Genetics
Environmental exposures
Infection
Infection
is suspected in many vasculitides, but not proven for many cases.
Recognizing
an infectious origin of
specific cases of vasculitis is of great importance
Treatment strategies
differ
from those applied to non-infectious or autoimmune forms.
Some infectious agents are known to cause vasculitis.
Viruses
Bacteria
Fungi
Parasites
Perhaps mycoplasmas
Many
viruses can be responsible for
systemic vasculitis.
The most frequent is
hepatitis B virus-related
polyarteritis nodosa (HBV-PAN),
Its incidence has decreased
over the past few decades.
Mixed
cryoglobulinemia has been shown
to be associated with hepatitis C virus (HCV) infection in more than
80% of the patients.
It remains asymptomatic in
most of them with
only a minority developing vasculitis.
Also
reported to be
associated with or implicated in the development of vasculitides are:
Human immunodeficiency virus
(HIV)
Erythrovirus B19
Cytomegalovirus
Also been reported to be
associated with or implicated in the development of vasculitides are:
Varicella-zoster virus
Human
T-cell lymphotropic virus (HTLV)-1
Bacteria,
fungi or parasites can also cause vasculitis in some cases.
The mechanisms are mainly by
direct invasion
of blood vessels.
Septic embolization can also
be a cause, leading,
e.g., to the
well-known feature of 'mycotic aneurysm'.
Syphilitic aortitis and/or
cerebrovascular disease and rickettsial diseases are other, more
specific, bacteria-induced vasculitides.
Investigation of
mycoplasmas is in early stages regarding vasculitides.
Effective
antimicrobial drugs are
mandatory to treat bacterial, parasitic or fungal infections
The the
combination of antiviral agents and plasma exchanges has been proven to
be effective against HBV-PAN.
This latter strategy might
also be
effective against HIV-associated vasculitis and, unlike cytotoxic
agents, does not jeopardize the outcome of HIV-infected patients.
In
the context of HCV-related
cryoglobulinemic vasculitis, antiviral drugs are necessary to achieve
recovery, in combination with low-dose corticosteroids and/or
rituximab.
In the near future, newer
antiviral agents will
probably also have their place in the therapeutic armamentarium for
these patients.
Some
medications may rarely cause a vasculitis.
Coumadin (Warfarin) has been
shown to be very rarely associated with a vasculitis, so rarely as to
be statistically insignificant.
[Adapted
and reformatted from an abstract for html and bulleted form ]