Clinical features and treatment interventions for human immunodeficiency virus-associated neurologic disease in children

Neurologic and neurodevelopmental manifestations of pediatric HIV/AIDS: a global perspective

Neurodevelopmental abnormalities associated with HIV infection have been described since the first reports of pediatric AIDS in the 1980s. Before antiretroviral therapy (ART) became widely available, progressive HIV-1 encephalopathy (PHE) was reported in the US in 13-35% of children with HIV-1 infection and in 35-50% of children with AIDS. Introduction of ART can prevent PHE and reverse PHE present at ART initiation, but a high prevalence of residual problems has been described. Even though 90% of HIV-infected children live in the developing world, few children have access to ART and little is known regarding the neurological manifestations of perinatal HIV infection in those regions. Mechanisms of pediatric HIV-1 neuropathogenesis and factors associated with neurodevelopmental abnormalities in perinatally infected children are not yet fully understood. Studies have demonstrated that HIV-1 enters the CNS soon after infection and may persist in this compartment over the entire course of HIV-1 infection. The CNS is a distinct viral reservoir, differing from peripheral compartments in target cells and antiretroviral penetration. Neurotropic HIV-1 likely develops distinct genotypic characteristics in response to this unique environment. We reviewed the literature on pediatric neuroAIDS and identified gaps in the current knowledge.

Interaction between Plasmodium falciparum and human immunodeficiency virus type 1 on the central nervous system of African children

Plasmodium falciparum and human immunodeficiency virus type 1 (HIV-1) infections are common in children living in sub-Saharan Africa (SSA). Both of these pathogens affect the central nervous system (CNS). Most HIV-1 infection of children in this region is acquired from infected mothers, particularly during breast-feeding and at the time of delivery. Over a third of children infected by birth will have died before their first birthday, before overt CNS manifestations have developed. The most common manifestations of primary CNS infection include neurodevelopmental delay, impaired brain growth, motor deficits, and behavioral problems. These deficits may also result from infections, neoplasm, or stroke. Cognitive impairments become more evident if the child survives for longer, but in Africa, children rarely survive past their fifth birthday. In malaria endemic areas, severe falciparum malaria usually develops after 6 months of age, and most of the CNS manifestations are more common in children over 1 year old. About 11% of children develop neurological deficits following cerebral malaria, most of which improve within 2 years of the insult. However, up to 24% of children may have neurocognitive impairments following severe malaria. The effect of milder malaria and coincidental parasitization on cognitive function is unknown. Other comorbidities that are common in SSA, such as malnutrition or micronutrient deficiencies, may influence children's neurodevelopment. The coinfection of malaria and HIV-1 may aggravate the neurodevelopmental impairments documented in these children. However, to date there are little published data, although it may have a profound effect of children living in SSA.

HIV-1 encephalopathy among perinatally infected children: Neuropathogenesis and response to highly active antiretroviral therapy

HIV-1 encephalopathy among perinatally infected children in the United States was initially defined by a classic triad of findings that included: (1) developmental delay, (2) secondary or acquired microcephaly, and (3) pyramidal tract neuromotor deficits. The most severe form of this disorder typically occurred among young children who developed rapidly progressive disease in concert with profound immunosuppression, and Pneumocystis jiroveci pneumonitis (PCP). The neuropathogenesis of this disorder appears to involve a cascade of viral products, various cytokines and chemokines, and neurotransmitters which promote ongoing inflammation, excitation, and overstimualtion of the N-methyl-D-aspartate type receptor (NMDAR) system. These subsequently lead to neuronal injury and death secondary to apoptosis or necrosis, astrocytosis, as well as dentritic and synaptic damage. The frequency of the most severe forms of encephalopathy among children has dropped dramatically since the introduction of highly active antiretroviral therapy (HAART). Of concern, however, is the possibility that a more insidious form of this disorder may be occurring presently among older vertically infected children as a result of inadequate penetration of HAART agents into the cerebrospinal fluid (CSF). This paper will review what published data there is as yet that bears on this question.

Neurocognitive outcomes in pediatric HIV

Cognitive impairment has long been associated with the natural history of HIV among vertically infected children. In children, HIV may have a direct or indirect impact on the developing brain, may lead to global or highly specific consequences, and may be responsible for minor cognitive consequences or, conversely, long-term and severe disability. This differential impact is related to multiple factors that influence the individual expression of the virus in any given child. This review provides an overview of the relevant literature on neurocognitive outcomes for infants, children, and youth vertically infected with HIV, with attention to those factors impacting neurocognitive outcome within a developmental framework. Research findings in both the era preceding and following the introduction of combined therapies are reviewed, since many of the issues identified prior to state-of-the-art treatment currently available in the United States and other developed countries still apply in much of the developing world. Intervention issues and directions for future research are also discussed.

Neurologic aspects of HIV infection in infants and children: therapeutic approaches and outcome

Central nervous system (CNS) HIV-related disorders frequently have devastating consequences. Significant progress has been made in the early diagnosis and treatment of the HIV-infected patient. As a result, the prevalence and natural history of neurologic illnesses have changed. This paper reviews the epidemiology, clinical manifestations, and neuropathogenesis of HIV-related CNS disorders. Advances in antiretroviral therapy, neuroprophylaxis, and neuroprotective strategies are also discussed.

Effect of combination antiretroviral therapy on cerebrospinal fluid HIV RNA, HIV resistance, and clinical manifestations of encephalopathy

OBJECTIVES

This study evaluated the effect of treatment with abacavir/lamivudine/zidovudine versus lamivudine/zidovudine on cerebrospinal fluid (CSF) human immunodeficiency virus (HIV) RNA and clinical manifestations of HIV encephalopathy in children.

STUDY DESIGN

HIV-infected children 7 months to 10 years of age (n = 23) were studied. CSF and plasma were obtained at baseline and weeks 8, 16, and 48. Genotype analysis of HIV was attempted at baseline and week 48. Neurologic evaluations were performed at baseline and weeks 16, 32, and 48.

RESULTS

At baseline, 83% of children had >2.00 log(10) copies/mL HIV RNA in CSF, but only 10% had HIV RNA measurable at week 48. Among children in whom paired genotyping of HIV was possible, 8 of 11 had identical patterns in both CSF and plasma at baseline, whereas at week 48, only 1 of 9 children had similar patterns. Neurologic abnormalities were observed in 83% of children at baseline but only 35% of children at week 48 (P =.004), suggesting a benefit of treatment.

CONCLUSIONS

Antiretroviral therapy was associated with a decline in CSF HIV RNA and an improvement in neurologic status. The development of genotypic mutations was different in CSF and plasma, suggesting discordant viral evolution. These results suggest that antiretroviral treatment in children should include agents with activity in the CNS.