Vasculitis

British Medical Journal, May 13, 2000 by C O S Savage, L Harper, P Cockwell, D Adu, A J Howie

ABC of arterial and vascular disease

Vasculitis is inflammation of blood vessel walls. The clinical and pathological features are variable and depend on the site and type of blood vessels that are affected. Diseases in which vasculitis is a primary process are called primary systemic vasculitides.

The main types of vasculitides can be described using clinical features and pathological findings according to the Chapel Hill Consensus Conference. These names and definitions will be followed in this article. Definitive classification of systemic vasculitis is unsatisfactory since aetiology and pathogenesis are rarely known, and clinical and histological features overlap. Vasculitis may also occur as a secondary feature in other diseases, such as systemic lupus erythematosus and rheumatoid arthritis.

Fever, night sweats, malaise, myalgia, and arthralgia are common in all types of vasculitis. Active vasculitis is usually associated with an acute phase response with an increase in C reactive protein concentration, erythrocyte sedimentation rate, or plasma viscosity.

Large vessel vasculitis

Giant cell arteritis (temporal arteritis)

Clinical features include unilateral throbbing headache, facial pain, and claudication of the jaw when eating. Visual loss is a feared symptom and may be sudden and painless, affecting part or all of the visual field. Diplopia may also occur. Giant cell arteritis is the most common type of primary systemic vasculitis with an incidence of 200/million population/year.

Treatment is with high dose corticosteroids (40-60 mg/day), which should be started as soon as the diagnosis is suspected to avoid visual loss. The diagnosis is confirmed by biopsy of the affected artery, done within 24 hours of starting corticosteroids. The corticosteroid dose may be reduced to 10 mg/day over six months and then more slowly to a maintenance of 5-10 mg/day. Maintenance treatment may be required for two years. The disease is monitored by measuring C reactive protein concentrations, erythrocyte sedimentation rate, or plasma viscosity.

Takayasu's arteritis

Takayasu's arteritis is most common in Asia and the Far East and affects women more than men. Disease of the arteries supplying the arms, head, neck, and heart leads to the aortic arch syndrome with claudication of the arm, loss of arm pulses, variation in blood pressure of more than 10 mm Hg between the arms, arterial bruits, angina, aortic regurgitation, syncope, stroke, and visual disturbance. The descending aortic syndrome may cause bowel ischaemia or infarction, renovascular hypertension, and renal impairment.

Diagnosis is by angiography or magnetic resonance angiography. Treatment of acute disease in patients with high C reactive protein concentration or erythrocyte sedimentation rate is with corticosteroids. Cytotoxic drugs such as cyclophosphamide can be added if steroids alone do not control the disease. Surgery or angioplasty may be required for stenoses once active inflammation has been controlled.

Medium vessel vasculitis

Polyarteritis nodosa

Polyarteritis nodosa is uncommon in the United Kingdom. It is associated with hepatitis B virus in some patients. Arterial disease leads to ischaemia or infarction within affected organs. The condition can affect the gut causing bleeding or perforation, the heart causing angina or myocardial infarction, the kidneys causing cortical infarcts leading to hypertension and renal failure, and the peripheral nerves causing mononeuritis multiplex. Hepatitis may reflect the presence of hepatitis B virus.

Diagnosis is based on the presence of arterial aneurysms on angiography of the renal, hepatic, splanchnic, or splenic circulations. Biopsy of affected muscle or nerve may confirm the presence of vasculitis. Treatment of polyarteritis associated with hepatitis B virus requires an antiviral drug such as interferon alfa combined with short course, high dose corticosteroids and plasma exchange. Non-hepatitis B virus polyarteritis usually responds to corticosteroids alone, although cyclophosphamide may be required for patients with more severe disease.

Kawasaki disease

Kawasaki disease affects children, usually under the age of 12 years. In Japan the incidence exceeds 100/100 000 children younger than 5 years but is less than 5/100 000 in this age group in the United Kingdom.

The most serious feature of Kawasaki disease is coronary artery disease; aneurysms occur in a fifth of untreated patients and may lead to myocardial infarction. They can be detected by echocardiography. High dose intravenous immunoglobulins reduce the prevalence of coronary artery aneurysms, provided that treatment is started within 10 days of onset of the disease. Low dose aspirin is recommended for thrombocythaemia.

Small vessel vasculitis associated with antineutrophil cytoplasmic antibody

Small vessel vasculitides are being recognised more frequently, mainly because of increased awareness. Estimates of incidence have increased from fewer than 5 cases per million population in the early 1980s to over 20 per million. The early symptoms of these disorders are non-specific with fever, malaise, arthralgia, myalgia, and weight loss, and patients in whom such symptoms are persistent should be screened for antineutrophil cytoplasmic antibodies (ANCA); have their erythrocyte sedimentation rate and C reactive protein concentration measured; and have their urine tested for blood with a dipstick. Early diagnosis is essential to prevent potentially life threatening renal and pulmonary injury. Delays in diagnosis are unfortunately common, and this often leads to serious morbidity. Once respiratory or renal disease develops, the course is usually rapidly progressive.