Therapeutic aspects of retroviral disease

Retroviruses of the nervous system cause HTLV-1-associated myelopathy and HIV-associated diseases. The treatment of HTLV-1 disease is essentially conservative; there is no effective drug treatment and therefore patients should be simply supported and reassured. If appropriate, other members of the family should be tested for HTLV-1 disease and counselled. The effects of HIV on the nervous system are much more complex. Therapy must take account of the diverse complications of HIV disease. Patients are probably best managed in specialized clinics which can cope with the different manifestations of the disease. Zidovudine (AZT) is the only effective anti-HIV drug that is licensed. It is indicated in complicated seroconversion disease and for any manifestation of HIV progression including AIDS dementia complex. Management of severe neurological disease depends critically on the ability to diagnose and treat CNS-specific opportunistic infections. Whether zidovudine is indicated for early asymptomatic disease when CD4 counts are below 500 microliters-1 is controversial. The main problems of zidovudine are reversible anaemia which results in about 30% of patients not tolerating long-term use, and the development of drug resistance which may be associated with clinical failure of the drug. Other, new and experimental drug treatments are discussed but none of them has as yet shown any convincing evidence of efficacy. Future improvements in treatment appear to depend on the development of effective multiple drug regimens (concurrently or sequentially) which will overcome the challenge of drug resistance.