Vasculitis

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October 18, 2001

QUESTION: How often does vasculitis present as myositis?

Hoffman, M.D. responds:

Although myalgias are a common complaint among patients with different

forms of vasculitis, frank vasculitis/myositis is infrequent. Consider

these examples:

Type of Vasculitis .....

Giant cell arteritis ..... Frequency of myalgias = 30-50%

Takayasu's arteritis ... Frequency of myalgias = 30-60%

Wegener's granulomatosis....Frequency of myalgias = 40-70%

Polyarteritis nodosa....Frequency of myalgias = 30-80%

Churg Strauss syndrome....Frequency of myalgias = 30-50%

Whereas these relatively high frequencies have been noted in various

series, muscle biopsy proof of vasculitis/myositis or increase in muscle

enzymes is anecdotal.

One could argue that vasculitis is the cause of myalgias/myositis or

arthralgias but is under-recognized because of accrual bias. (Biopsies

are not usually done.) However, consider that clinicians have long

recognized myalgias to be a common feature of many systemic illnesses

that are completely reversible and not associated with vasculitis. This

would suggest that events such as cytokine release, in the setting of

certain systemic illnesses, may play an important role but not one that

leads to ischemia, infarction, or sufficient injury to muscle to cause

muscle enzyme elevation in peripheral blood.