HIV-1-related encephalopathy in infants compared with children and adults

Objective: To characterize the specificities of HIV-1-related encephalopath y in children. Methods: Comparison of patients from the French Perinatal Co hort of children born to HIV-1-infected mothers and followed from birth wit h the French SEROCO Cohort of adults with a known date of infection. Our st udy examines 1) the characteristics of encephalopathy with onset before 1 y ear, after 1 year, and in adults, and 2) the maternal and birth characteris tics of infants who developed AIDS before 1 year and went on to develop eit her encephalopathy or opportunistic infection. Results: The incidence of en cephalopathy was higher in children than in adults during the first year (9 .9% versus 0.3%) and intermediate during the second year (4.2% versus 0%) a fter infection but was similar thereafter (less than 1% per year in each gr oup). The resulting cumulative incidence at 7 years postinfection reached 1 6% in children and 5% in adults. Encephalopathy that developed before 1 yea r 1) was more frequently an isolated symptom of AIDS, 2) was associated wit h a reduction of intrauterine brain growth, 3) was associated with a very l ow level of HIV-1 RNA in CSF, 4) occurred at a higher level of immunocompet ence after taking into account the decrease in CD4 lymphocytes with age, an d 5) was not prevented by zidovudine treatment during gestation. Conclusion s: Early encephalopathy in infants has a different pathophysiologic mechani sm than that occurring in children, which in turn shows similarities with t hat observed in adults. Early encephalopathy is probably related to the occ urrence of pathologic events during late fetal life.