The incidence and clinical progression of HIV encephalopathy among 128 HIV-perinatally infected children were studied at multiple US centers by the Women and Infants Transmission Study Group. During a median follow-up of 24 months, HIV encephalopathy was diagnosed in 27 (21%), with a median survival of 14 months and a mortality rate of 41%. In the encephalopathy cases, immunosuppression was present in 20 (74%), hepatosplenomegaly or lymphadenopathy in 63%, and cardiomyopathy in 30%. Failure to gain weight predated the onset of encephalopathy in infected infants. HIV infected children without encephalopathy had a lower incidence of hepatosplenomegaly (29%) and cardiomyopathy (2%), diagnosed in the first 3 months of life. Risk of encephalopathy was related to a high viral load in infancy. 
COMMENT. Encephalopathy is a frequent complication of perinatally acquired HIV infection, occurring in one in 5 infants. A high viral load during the neonatal period, failure to thrive, and early signs of organomegaly and lymphadenopathy are risk factors for HIV encephalopathy.