The ‘vasculitides’ encompass a wide range of diseases with considerable overlap between them. Many different classifications have been suggested and only better understanding of these conditions will clarify the situation. In the meantime, they are usually classified according to the predominant type of vessel involvement.
Polyarteritis nodosa (PAN) group
here is much overlap within this group. The classic PAN is a rare condition and, unlike other connective tissue disorders, it usually presents in middle-aged men. It is accompanied by severe systemic manifestations and its association with hepatitis B antigenaemia suggests a vasculitis secondary to the deposition of immune complexes. Pathologically, there is fibrinoid necrosis of vessel walls with microaneurysm formation, thrombosis and infarction.
Classic PAN does not involve the lung. The Churg-Strauss syndrome is associated with allergic angiitis and granuloma formation accompanied by an intense eosinophilic infiltration that affects the pulmonary arteries and causes asthma and pneumonia.
Microscopic polyarteritis is an inflammation of capillaries involving many organs, e.g. kidneys and the lungs resulting in pulmonary haemorrhage.
ANCA is particularly associated with microscopic polyarteritis and is usually negative in classic PAN. It may playa role in the pathogenesis of this condition.
In classic PAN the initial features are non-specific, being fever, malaise, severe weight loss, myalgia and arthralgia. Later the most characteristic features are renal impairment, hypertension, polyneuropathy, lung disease and cardiac problems, including arrhythmia, heart failure and myocardial infarction. The polyneuropathy in vasculitic disorders characteristically takes the form of a mononeuritis multiplex . A migratory arthralgia or arthritis with fever are seen, and abdominal pain, due to liver and gastrointestinal tract involvement, is common. Death is usually from renal disease.
The ESR is raised but the diagnosis depends upon either histological examination of biopsy material from an affected organ or angiographic demonstration of microaneurysms in hepatic, intestinal or renal vessels.
Treatment is with corticosteroids, usually in combination with immunosuppressive drugs such as azathioprine. Essential mixed cryoglobulinaemia In this disorder a cutaneous vasculitis is associated with cryoglobulinaemia. It is exacerbated by exercise and the cold, and there is an association with hepatitis B infection. Multisystem involvement occurs as in other connective tissue disorders.
Vasculitis associated with granulomas
Two forms of vasculitis associated with granulomas are Wegener’s granulomatosis and the Churg-Strauss syndrome. Wegener’s granulomatosis classically consists of the triad of upper respiratory tract granuloma, fleeting pulmonary shadows, and glomerulonephritis; it is discussed.
Polymyalgia rheumatica and giantcell arteritis
Polymyalgia rheumatica and giant-cell artentis (also known as temporal or cranial arteritis) can be regarded as two conditions at the ends of a spectrum, with giantcell arteritis as the basic pathological lesion. The cause is unknown. Occasionally the syndrome of polymyalgia is due to some underlying condition, e.g. a severe infection or a malignancy.
Polymyalgia rheumatica is characterized by pains and morning stiffness in the proximal muscles of the shoulder and pelvic girdle, and a high ESR. The onset is sudden. It is rare before the age of 50 years and usually occurs in those aged 60-70 years. Women are three times more commonly affected than men. Severe pains and stiffness occur in the girdle muscles and also in the muscles of the cervical and lumbar spines. The hands and feet are never affected. Early morning stiffness often causes difficulty in getting out of bed. Systemic symptoms include malaise, anorexia, weight loss and a low-grade fever. Painful restriction of movement of the shoulders and hips is characteristic. The distribution of joint involvement is bilateral and symmetrical. Occasionally knees and wrists are involved. There may be no physical signs if the patient is examined in the afternoon when the stiffness has worn off.
Headache, particularly if localized and accompanied by temporal tenderness and loss of pulsation, suggests a temporal arteritis, which rarely occurs with polymyalgia.
ESR is usually raised to a very high level (around 100 mm hour-I) but returns to normal with treatment.
MILD NORMOCHROMIC NORMOCYTIC ANAEMIA is present.
RHEUMATOID FACTOR TESTS are negative, though false-positive results are found particularly in older people.
SERUM ALKALINE PHOSPHATASE LEVELS are sometimes raised but return to normal with treatment. There is no specific test. It is not usual to carry out a temporal artery biopsy in polymyalgia, although a giantell arteritis can be demonstrated in 20% of cases. Temporal artery biopsy is often performed in temporal arteritis, but is not necessary in classic cases.
Corticosteroids are the treatment of choice in polymyalgia rheumatica, starting with 15 mg of prednisolone daily. NSAIDs are less effective and, as they do not control the arteritis, should not be used. Treatment should be started imediately the diagnosis is made and before waiting for the results of tests, in order to prevent irreversible blindness, although this is rare in the absence of temporal arteritis. With steroid therapy, patients feel better within days, though mobilization of stiff shoulders may take a month or two. The dose of prednisolone is slowly reduced over the course of the next 2 years in amounts not exceeding 1 mg and at intervals not less than 1 month. Relapses are common. In most patients it is posseble to stop treatment after 2-4 years.