Clinical disease of the nervous system accounts for a significant degree of morbidity in a high percentage of patients with HIV infection (Table 48-1). The neurologic problems that occur in HIV-infected individuals may be either primary to the pathogenic processes of HIV infection or secondary to opportunistic infections or neoplasms. Among the more frequent opportunistic diseases that involve the CNS are toxoplasmosis, cryptococcosis, progressive multifocal leukoencephalopathy, and primary CNS lymphoma. Other less common problems include mycobacterial infections; syphilis; and infection with CMV, HTLV-1, Trypanosoma cruzi, or Acanthamoeba. Overall, secondary diseases of the CNS have been reported to occur in approximately one-third of patients with AIDS. These data antedate the widespread use of cART, and this frequency is considerably lower in patients receiving effective antiretroviral drugs. Primary processes related to HIV infection of the nervous system are reminiscent of those seen with other lentiviruses, such as the Visna-Maedi virus of sheep.
TABLE 48-1NEUROLOGIC DISEASES IN PATIENTS WITH HIV INFECTION |Favorite Table|Download (.pdf) TABLE 48-1NEUROLOGIC DISEASES IN PATIENTS WITH HIV INFECTION
Primary CNS lymphoma
The current U.S. CDC classification system for HIV infection and AIDS categorizes people on the basis of clinical conditions associated with HIV infection and CD4+ T lymphocyte measurement. A confirmed HIV case can be classified in one of five HIV infection stages (0, 1, 2, 3, or unknown). If there was a negative HIV test within 6 months of the first HIV infection diagnosis, the stage is 0, and remains 0 until 6 months after diagnosis. Advanced HIV disease (AIDS) is classified as stage 3 if one or more specific opportunistic illness has been diagnosed (Table 48-2). Otherwise, the stage is determined by CD4 test results and immunologic criteria (Table 48-3). If none of these criteria apply (e.g., because of missing information on CD4 test results), the stage is U (unknown).
TABLE 48-2CDC STAGE 3 (AIDS)-DEFINING OPPORTUNISTIC ILLNESSES IN HIV INFECTION |Favorite Table|Download (.pdf) TABLE 48-2CDC STAGE 3 (AIDS)-DEFINING OPPORTUNISTIC ILLNESSES IN HIV INFECTION
|Bacterial infections, multiple or recurrenta |
|Candidiasis of bronchi, trachea, or lungs |
|Candidiasis of esophagus |
|Cervical cancer, invasiveb |
|Coccidioidomycosis, disseminated or extrapulmonary |
|Cryptococcosis, extrapulmonary |
|Cryptosporidiosis, chronic intestinal (>1 month’s duration) |
|Cytomegalovirus disease (other than liver, spleen, or nodes), onset at age >1 month |
|Cytomegalovirus retinitis (with loss of vision) |
|Encephalopathy attributed to HIV |
|Herpes simplex: chronic ulcers (>1 month’s duration) or ...|