Vasculitis encompasses a wide spectrum of disorders which are characterised by inflammation of blood vessels. Their severity depends on the size and site of vessels affected.
Vasculitic disorders tend to be systemic rather than localised and should be considered in any unidentified multisystem disorder.
Patients with vasculitis most commonly present with multisystem inflammatory disease. This is often represented by pyrexia; constitutional symptoms; suspicious skin lesions such as ulcers and palpable purpura; ischemic neuropathies; and organ dysfunction.
Vasculitis can occur at any age, however some classically present at certain ages:
This article is concerned with disorders arising from immune-mediated inflammation of vascular walls, however it is also possible for vasculitis to arise as a result of infectious pathogens and indeed these infections themselves can indirectly induce an immune-mediated vasculitis.
Immune-mediated vasculitis can result from any of the following mechanisms:
1. FBC (leucocytosis, thrombocytosis), ESR (>100), CRP (>10), U&E (?renal involvement), ANCA, ANA, RF, Complement levels (may be low due to consumption).
2. Urinalysis (?renal involvement: red blood cells and casts).
3. CXR (?pulmonary involvement).
4. Biopsy of skin lesion or involved organ.
Vasculitic disorders can be subdivided according to the main size of blood vessel affected. Small vessel vasculitis affects arterioles, venules and capillaries but may also affect larger vessels.
Small vessel vasculitis is an uncommon disorder typically affecting elderly patients and predominantly affecting Caucasians.
(Henoch-Schonlein purpura: see next section)
Aetiology: Primary small vessel vasculitis has an unknown aetiology.
Prognosis: 5-Year survival is 80%. Early death is usually due to opportunistic infection. Serious complications include pulmonary haemorrhage and end-stage renal disease.
Henoch-Schonlein purpura (HSP) is a systemic vasculitis most common in children and characterised by IgA deposition. The aetiology is unknown but it commonly follows an upper respiratory infection. It can be mistaken for meningococcal sepsis.
Diagnosis: Based on clinical symptoms and confirmed by tissue biopsy.
Medium vessel vasculitis affects small and medium-sized arteries but does not involve either major branches of the aorta or capillaries.
The two key disorders are:
Polyarteritis nodosa (PAN) is an uncommon disease and classically develops following a infection of hepatitis B virus (HBV) - although it is not a requirement.
Typically patients experience weight loss, arthralgia, myalgia, mononeuritis multiplex, gastrointestinal complications (ischemia, infarction, haemorrhage, perforation), ischemic heart disease, hypertension, livedo reticularis and testicular pain.
Renal and respiratory involvement should raise the possibility of an alternative vasculitic process.
PAN is ANCA negative.
Kawasaki disease (KD) is a self-limiting disorder, however if untreated, coronary-artery aneurysms can be a fairly common complication. KD is most common in Japan and is the leading cause of acquired paediatric heart disease worldwide.
Presentation is usually preceded by several days of gastrointestinal or respiratory symptoms with or without irritability (potentially due to aseptic meningitis). Diagnostic criteria has been developed however some features of the disease are not included.
[Abbreviated] Criteria: fever (with no other explanation) of at least 5 days PLUS 4 of 5 below:
[!]Consider the diagnosis of Kawasaki disease in any child with an unexplained febrile exanthematous illness - particularly if persisting >4 days.
Management: aspirin and intravenous immunoglobulin. Relapse can occur.
Large vessel vasculitis is characterised by inflammation of the aorta and its major branches.
The two main large vessel vasculitides are:
GIANT CELL ARTERITIS (TEMPORAL ARTERITIS):
Giant cell arteritis (GCA) has a predilection for the extra-cranial branches of the carotid artery, with the temporal arteries being commonly affected.
GCA is the commonest vasculitis. It occurs more frequently in women and usually occurs in patients aged over 50.
American College of Rheumatology (ACR) criteria for GCA diagnosis, 3/5 needed:
(A helpful tip is to remember the number 50!)
Takayasu's arteritis (TA) results in stenoses, occlusion, dilatation and aneurysm formation.
TA has a mean onset of age at 30 and is more common in asian persons.
The progression of TA is usually from an inflammatory phase (systemic symptoms) to development of ischemic symptoms.
American College of Rheumatology (ACR) criteria for TA diagnosis, 3/6 needed:
Autoimmune rheumatic disorders. Medicine, February 2010; 38:2.
Robbins Basic Pathology. Kumar et al. 8th Edition.
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