Gary 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.