Neurological complications of HIV-1 infection, due either to the immunosuppression (opportunistic infections and neoplasms) or the neurotropism of the virus, are common and add considerably to the morbidity and mortality of the infection
Their frequency varies according to the stage of the disease. They have been reported to represent 10-15% of symptomatic primo-infection, and are the first manifestation of AIDS in 10-20% of symptomatic HIV-1 infection cases.
Their prevalence in clinical studies has been estimated to range from 40 to 70%, and a prospective study revealed that neurological findings were present in 90% of AIDS patients examined by a neurologist [1]. Some autopsy series showed brain lesions in up to 100% of patients [2, 3].The incidence rate of HIV-1-associated neurological diseases has significantly decreased since the introduction of combined multitherapies, generally including a protease inhibitor (PI) and HAART (highly active antiretroviral therapy), and the widespread use of prophylactic medications for opportunistic infections [4]. From a neurological point of view, however, the success of HAART is tempered by the occurrence of numerous drug-related neurotoxic effects (neuropathies, seizures, mitochondrial myopathy, psychiatric disorders, etc.), the immune reconstitution’s pathology [5], the sanctuary provided by the nervous system for lentiviruses, and the development of resistance mutations with subsequent decline in CD4 cell counts. The incidence of HIV-1-associated neurological complications may begin to rise again because HIV-1 infection is now becoming a chronic disease [4]. Uncommon types of brain infection and new forms of encephalopathy are arising [6] and questions are emerging about the development of some neurodegenerative diseases. For all these reasons, the nervous system is still the second most frequently affected organ in HIV infection [7].
Among neurological complications in HIV-1 infection, cerebrovascular events were described long before the HAART era [8]. Yet, little is known about their real frequency and their specific etiologies [2, 9]. Several methodological limitations in the published literature have been noted, including the definition of stroke, the unclear identification of etiologies and the potential confounders, and the small sample size of the studies [10, 11]. Moreover, the epidemiology of human immunodeficiency virus (HIV) infection has changed in recent years, especially in Western countries. New infections in persons over the age of 50 have increased and seropositive individuals are aging due to the widespread use of HAART [reviewed in 12]. HIV-1-infected patients are therefore at higher risk for cerebrovascular diseases whatever the cause.