Myositis during Borrelia burgdorferi infection (Lyme disease).

During the second stage of an illness caused by Borrelia burgdorferi, a young woman developed a myopathic syndrome characterised by severe muscular pains, incapacitating weakness of the proximal limb and the neck, as well as the bulbar muscles and elevated serum CK levels. Muscle biopsy revealed a non-inflammatory necrotising myopathy. B. burgdorferi infection was confirmed by a considerable rise of specific IgG antibodies. A course of high dose steroids alleviated the myalgias, but paresis began to improve only after treatment with antibiotics. Our observations confirm that B burgdorferi can cause, through an undertermined mechanism, a necrotising myopathy, in addition to the wide spectrum of already known neurological complications.