Neurological complications of HIV infection

More than half of HIV - infected persons develop symptomatic neurological disease. The nervous system is extensively involved with no part of the neuraxis being immune from the virus. Beisdes the brain and spinal cord, the peripheral nerves and muscles may be affected. Neurological complications typically occur with advanced disease and profound immunosuppression, hence a knowledge of the CD4 lymphocyte count is of paramount importance. Since many of the conditions are amenable to treatment, a proper diagnosis and therapy may decrease morbidity in the already curtailed life span of the patient. Some opportunistic neurological infection is a result of latent/persistent infection requiring lifelong secondary prophylaxis e.g. toxoplasma encephalitis and cryptococcal meningitis. Neuroaids does not follow the law of parsimony i.e. a single entity may not be responsible for the entire constellation of signs and symptoms. HIV infection is the commonest cause of dementia in people under the age 50 in the developed world. Cryptococcosis is the commonest infection affecting the nervous system in HIV positive patients. Tuberculosis has seen a resurgence following the out break of AIDS. CNS lymphoma is the commonest cause of raised ICP followed by tuberculoma, toxoplasmosis and brain abscess. Most patients with paraparesis have a typical HIV associated vacuolar myelopathy, A distal predominantly sensory neuropathy is the initial feature of insult to peripheral nerves. Muscle involvement may be due to polymyositis and HIV associated wasting syndrome but may also be aggravated by drugs (e.g. zidoudine).