MUSCLE DISEASE, HIV AND ZIDOVUDINE - THE SPECTRUM OF MUSCLE DISEASE IN HIV-INFECTED INDIVIDUALS TREATED WITH ZIDOVUDINE

Eleven patients with AIDS or AIDS-related complex who developed muscle -related symptoms whilst taking zidovudine were investigated. The clin ical details of a further ten patients who did not undergo muscle biop sy are also outlined. The clinical features, quantitative muscle stren gth testing, electromyographic findings, serial creatine kinase levels , muscle biopsy appearance on light microscopy and the effects of zido vudine withdrawal and rechallenge are described. The spectrum of muscl e disease encountered included four cases of frank myopathy diagnosed using clinical, electrophysiological and histological criteria, four p atients with mild weakness and myalgia in whom muscle biopsies were no rmal, three patients with myalgia only and a mild increase in the inte rstitial cell infiltrate shown by biopsy. The patients presenting with myopathy showed no improvement on withdrawal of zidovudine but respon ded to immunosuppressive therapy with steroids and, in one case, thali domide prescribed incidentally. At present, it is not yet possible to clinically define a specific zidovudine-induced myopathy that is disti nct from the other effects of HIV infection on muscle structure and fu nction. Our experience suggests that zidovudine may be implicated as a myotoxin in some patients, particularly those with myalgia and mild w eakness. In those patients with severe weakness, and with biopsy findi ngs of necrosis and inflammation, the drug effects may be difficult to separate from the primary effects of HIV.