Effect of continuous-infusion zidovudine therapy on neuropsychologic functioning in children with symptomatic human immunodeficiency virus infection

Perinatally acquired HIV infection: long-term neuropsychological consequences and challenges ahead

Over the past three decades, perinatal HIV infection in the United States has evolved from a fatal disease to a manageable chronic illness. As the majority of youth with perinatal HIV infection age into adolescence and adulthood, management of this stigmatizing, transmittable disease in the backdrop of a cadre of environmental stressors presents challenges beyond those of other chronic illnesses. The neurologic and neuropsychological consequences of this neurotropic virus have important implications for the successful navigation of responsibilities related to increasingly independent living of this aging population. This article will review the neurologic and neuropsychological consequences of perinatal HIV infection and concomitant factors in the era of highly active antiretroviral therapy and will provide an overview of the neuropathology, pathogenesis, neuroimaging findings, and treatment of perinatal HIV infection, as well as recommendations for service provision and future research.

Poor health-related quality of life and abnormal psychosocial adjustment in Italian children with perinatal HIV infection receiving highly active antiretroviral treatment

To evaluate health-related quality of life (HRQL), social competence, and behavioral problems in children with perinatal HIV infection receiving highly active antiretroviral therapy (HAART), a cross-sectional study was performed at the Department of Pediatrics, University of Brescia. We evaluated HRQL, social competence, and behavioral problems in 27 HIV-infected children compared with age and sex-matched control subjects using the Pediatric Quality of Life Inventory (PedsQL) and the Child Behavior Checklist (CBCL), respectively. On the PedsQL 4.0 Generic Core Scale, HIV-infected subjects displayed significantly reduced physical (p=0.043) and psychosocial health (p=0.021) functioning, particularly at school (p=0.000), compared with healthy subjects, resulting in a significantly reduced total score (p=0.013). Assessment of social competence and the behavioral features of HIV-infected children by means of the CBCL revealed severe limitations of functioning in HIV-infected children who had impaired social ability. Children with HIV-RNA above the threshold level of 50 had higher scores on the CBCL delinquent behavior (p=0.021) and school competence (p=0.025) subsets. Although the introduction of HAART regimens has prolonged the survival of HIV-infected children, other factors, including disease morbidity and familial and environmental conditions, negatively affect their quality of life, thereby contributing to increased risk for behavioral problems.

Growing up with HIV: children, adolescents, and young adults with perinatally acquired HIV infection

Tremendous success in the prevention and treatment of pediatric HIV in high-resource countries has changed the face of the epidemic. A perinatally HIV-infected child now faces a chronic disease rather than a progressive, fatal one. However, these successes pose new challenges as perinatally HIV-infected youth survive into adulthood. These include maintaining adherence to long-term, likely life-long therapy; selecting successive antiretroviral drug regimens, given the limited availability of pediatric formulations and the lack of pharmacokinetic and safety data in children; and overcoming extensive drug resistance in multi-drug-experienced children. Pediatric HIV care now focuses on morbidity related to long-term HIV infection and its treatment. Survival into adulthood of perinatally HIV-infected youth in high-resource countries encourages expansion of pediatric treatment programs in low-resource countries, where most HIV-infected children live, and provides important lessons about how the epidemic changes with increasing access to antiretroviral therapy for children.

Neurodevelopmental trajectory of HIV-infected children accessing care in Kinshasa, Democratic Republic of Congo

OBJECTIVE

To assess the effect of HIV care (including highly active antiretroviral therapy if eligible) on neurodevelopment.

DESIGN

Prospective cohort study.

METHODS

Motor and mental development of 35 HIV-infected children (aged 18-71 months) was assessed at entry into care and after 6 and 12 months using age-appropriate tools. Developmental trajectory was compared with 35 HIV-uninfected, affected, and 90 control children using linear mixed-effects models. Effects of age (29 months) and timing of entry into care (before or after highly active antiretroviral therapy eligibility) were explored in secondary analyses.

RESULTS

At baseline, HIV-infected children had the lowest, control children the highest, and HIV-uninfected affected children intermediate mean developmental scores. After 1 year of care, HIV-infected children achieved mean motor and cognitive scores that were similar to HIV uninfected, affected children although lower compared with control children. Overall, HIV-infected children experienced accelerated motor development but similar gains in cognitive development compared with control children. Exploratory analyses suggest that younger children and those presenting early may experience accelerated greater gains in development.

CONCLUSIONS

HIV-infected children accessing care experience improved motor development, and may, if care is initiated at a young age or an early stage of the disease, also experience gains in cognitive development.

Impact of HAART and CNS-penetrating antiretroviral regimens on HIV encephalopathy among perinatally infected children and adolescents

OBJECTIVES

Prior to antiretroviral treatment, HIV-infected children frequently developed encephalopathy, resulting in debilitating morbidity and mortality. This is the first large study to evaluate the impact of HAART and central nervous system (CNS)-penetrating antiretroviral regimens on the incidence of HIV encephalopathy and survival after diagnosis of HIV encephalopathy among perinatally infected children.

DESIGN

A total of 2398 perinatally HIV-infected children with at least one neurological examination were followed in a US-based prospective cohort study conducted from 1993 to 2007.

METHODS

Trends in incidence rates over calendar time were described and Cox regression models were used to estimate the effects of time-varying HAART and CNS-penetrating antiretroviral regimens on HIV encephalopathy and on survival after diagnosis of HIV encephalopathy.

RESULTS

During a median of 6.4 years of follow-up, 77 incident cases of HIV encephalopathy occurred [incidence rate 5.1 cases per 1000 person-years, 95% confidence interval (CI) 4.0-6.3]. A 10-fold decline in incidence was observed beginning in 1996, followed by a stable incidence rate after 2002. HAART regimens were associated with a 50% decrease (95% CI 14-71%) in the incidence of HIV encephalopathy compared with non-HAART regimens. High CNS-penetrating regimens were associated with a substantial survival benefit (74% reduction in the risk of death, 95% CI 39-89%) after HIV encephalopathy diagnosis compared with low CNS-penetrating regimens.

CONCLUSION

A dramatic decrease in the incidence of HIV encephalopathy occurred after the introduction of HAART. The use of HAART was highly effective in reducing the incidence of HIV encephalopathy among perinatally infected children and adolescents. Effective CNS-penetrating antiretroviral regimens are important in affecting survival after diagnosis of HIV encephalopathy.

The impact of environmental risk factors on HIV-associated cognitive decline in children

Both the human immunodeficiency virus (HIV) and environmental stress have been independently associated with decreased cognitive functioning in children. Given that they are also known to have a strong relationship with each other, the present study sought to test the hypothesis that children in conditions of high environmental risk would be at greater risk for the cognitive complications related to immunosuppression. A retrospective review was conducted to examine the records of 141 children treated at a large pediatric AIDS clinic from 1993 to 2000. CD4+ lymphocyte levels were recorded from laboratory results and IQ scores were recorded from routine psychological evaluations. Key indicators of environmental risk were collected and combined into one measure of overall environmental risk. Pearson product moment correlations were conducted to examine the relationship between environmental risk, age-adjusted CD4 and IQ. Results indicated a significant correlation between CD4 and IQ, with higher levels of immunocompetence predicting higher IQ scores. When subjects were dichotomized based on their environmental risk score, there was no relationship between CD4 count and IQ in the low environmental risk group. In contrast, CD4 was positively associated with IQ in the high environmental risk group. It is proposed that this may be due to gp120 levels in immunocompromised children being particularly toxic to the hippocampus and cortex under conditions of high stress but not so under conditions of low stress.

Immunologic, virologic, and neuropsychologic responses in human immunodeficiency virus-infected children receiving their first highly active antiretroviral therapy regimen

Our objective was to measure the early dynamics, evolution, and durability over 96 wk of immunologic responses in children receiving their first highly active antiretroviral therapy (HAART) regimen. The study was designed as a prospective, single-arm study. Twelve human immunodeficiency virus (HIV)-infected children (median age, 11.8 yr) were enrolled. All subjects received stavudine, nevirapine, and ritonavir. Serial measurements included HIV viral load, lymphocyte subsets, thymic volume by computed tomography (CT), neurocognitive testing, and brain CT. Baseline median CD4(+) T cell count was 589 cells/mm(3) , viral load was 3.9 log(10) HIV RNA copies/mL, and thymic volume was 16.3 cm(3) . Ten children had an undetectable viral load at week 48. Eight maintained an undetectable viral load at 96 wk. The median increase in absolute CD4(+) T cell count was 225 cells/mm(3) by week 48, and 307 cells/mm(3) by week 96. The median increase in naive (CD45RA(+) CD62L(+) ) CD4(+) T cells was 133 cells/mm(3) by week 48, and 147 cells/mm(3) by week 96. The median number of naive CD8(+) T cells increased from 205 to 284 cells/mm(3) by week 24; this increase was sustained to week 96. The number of B cells increased and was associated with a decrease in immunoglobulin levels. The number of natural killer cells was stable. There were no significant changes in thymic volume. Most children exhibited stable cognitive function over the course of the study. We conclude that, in this cohort of relatively immunocompetent HIV-infected children, an initial HAART regimen was associated with rapid and sustained increases in total CD4(+) T cells, in naive CD4(+) and CD8(+) T cells, and in B cells through 96 wk.

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.

Cognitive functioning in school-aged children with vertically acquired HIV infection being treated with highly active antiretroviral therapy (HAART)

In today's era of highly active antiretroviral therapy (HAART), few children with HIV-1 infection experience severe central nervous system (CNS) manifestations indicative of encephalopathy. However, little is known about the neurocognitive strengths and weaknesses of HIV-infected children treated with HAART. This cross-sectional study is the first to systematically investigate the relation between cognitive functioning and medical markers in HIV-infected children and adolescents treated with HAART with varying levels of computed tomography (CT) brain scan abnormalities. The Wechsler Intelligence Scale for Children-Third Edition was administered to 41 vertically infected children (mean age = 11.2 years) treated with HAART for at least 1 year. Other procedures at the time of testing included CT brain scans and collection of CD4 cell counts and plasma HIV1 RNA PCR. Although global cognitive functioning among participants was in the Average range, children with minimal to moderate CT brain scan abnormalities scored significantly lower than children with normal scans on composite measures of cognitive functioning and five specific subtests, especially tasks involving executive functions. Furthermore, children with worse immune status (CD4+ counts < or = 500) scored lower on subtests measuring processing speed. Viral load was unrelated to cognitive test scores. Thus, children with HIV being treated with HAART remain at risk for developing CNS disease. Findings emphasize the importance of conducting neuropsychological assessments in this population, particularly for children with cortical atrophy and absolute CD4+ cell counts < or = 500.

Effects of highly active antiretroviral therapy (HAART) on psychomotor performance in children with HIV disease

OBJECTIVE

This study assesses the effects of HAART on psychomotor performance of symptomatic HIV-infected children. It is one of the first studies to look at neurobehavioral functioning in children infected with HIV in resource-limited countries.

DESIGN

A longitudinal pilot study of vertically HIV-infected children at the HIV Netherlands Australia Thailand Research Collaboration Center in Bangkok, Thailand.

METHODS

A total of 34 children participated in the study of whom 16 had never received antiretroviral (ARV) therapy and were about to start HAART (Newly treated children), 7 did not receive antiretroviral therapy (Untreated children) and 11 had been treated with HAART for more than one year (HAART experienced children). All children were administered 4 psychomotor tasks at baseline and after 4 months. The Newly treated and the Untreated children were also evaluated after 12 months.

RESULTS

In general, the children performed similarly on all psychomotor tasks at baseline. After 12 months of HAART, there was a significant increase in CD4% in the Newly treated group. Overall, psychomotor performance did not change at the 4-month evaluation in all groups. At the 12-month evaluation psychomotor performance had deteriorated substantially on all tasks in both the Newly treated and the Untreated children.

CONCLUSIONS

There was no significant difference in psychomotor functioning between children newly treated, previously treated and untreated with HAART over the course of one year. Psychomotor performance deteriorated after 12 months of HAART, which provides important indications concerning the lack of benefits of HAART on psychomotor functions in children despite immunologic reconstitution. Further research with larger sample sizes is needed to confirm these findings.

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.

Youths and HIV/AIDS: psychiatry's role in a changing epidemic

OBJECTIVE

To review the past 10 years of published research on human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) in the United States, including psychosocial and psychiatric risk factors, epidemiology, biology, neurocognitive and psychiatric sequelae, disclosure issues, prevention strategies, and biological and behavioral treatments.

METHOD

Researchers reviewed the English-language literature with a focus on child and adolescent risk factors associated with HIV/AIDS, prevention, and treatment.

RESULTS

Substantial scientific advances have occurred over the past two decades leading to decreased morbidity and mortality in the United States from AIDS-related opportunistic infections. At the same time, rates of HIV infection are increasing in teenagers, young women, and minorities, and growing numbers of youths are living with an infected family member. Understanding HIV risk behavior requires a broad theoretical framework. Comprehensive HIV prevention programs have led to reduced risk behavior among HIV-affected youths and teens at risk of infection. Biological and behavioral treatments of HIV infection continue to evolve and have led to longer life span, improved quality of life, and fewer psychiatric problems.

CONCLUSIONS

HIV/AIDS has significant mental health implications, and psychiatry can play a critical role in curbing the epidemic. With minimal effort, mental health professionals can adapt and apply the strategies that they use to treat psychiatric symptoms to prevent HIV transmission behaviors.

Incidence and prevalence of HIV encephalopathy in children with HIV infection receiving highly active anti-retroviral therapy (HAART)

OBJECTIVE

To describe neurologic outcomes in children infected with HIV in the era of highly active anti-retroviral therapy (HAART), including rates of progressive HIV encephalopathy (PHE) and clinical sequelae among PHE survivors.

STUDY DESIGN

Neurobehavior and school placement was assessed prospectively in the year 2000 in 126 children infected with HIV. PHE, developmental delay, and attention deficit disorder (ADHD) were the main outcome variables analyzed. Predictors of PHE were assessed in controlled analysis among age-matched controls.

RESULTS

The rate of active PHE in 2000 was 1.6% (n = 2), and the prevalence of arrested PHE was 10% (n = 13). Residual motor and cognitive sequelae and need for special education was found in the majority of survivors. PHE relapse occurred in 3 (23%) children with previously arrested PHE. Viral load (VL) was the only significant factor associated with PHE. HIV or PHE was not associated with ADHD. Isolated developmental delay was not associated with HIV.

CONCLUSIONS

PHE is an infrequent and reversible complication of HIV infection that responds to HAART and that may relapse if control of the virus is lost. Children with arrested PHE show higher rates of residual neurologic, cognitive, and scholastic impairments compared with children who never had PHE. Children with arrested PHE are the group of children with HIV infection most at risk for PHE, in the form of a relapse.

Neuropsychological functioning and viral load in stable antiretroviral therapy-experienced HIV-infected children

OBJECTIVE

Neuropsychological functioning and its correlation with viral load were investigated for previously treated HIV-infected children who underwent a change in treatment regimen.

METHODS

Thirteen age-appropriate measures of cognitive, neurologic, and behavioral functioning were administered to 489 HIV-infected children who were aged 4 months to 17 years and had been treated previously for at least 16 weeks with antiretroviral therapy. These clinically and immunologically stable children were randomized onto 1 of 7 drug treatment combinations, 6 of which included a protease inhibitor (PI), and evaluated prospectively for 48 weeks with respect to changes in neuropsychological performance and viral load.

RESULTS

Neuropsychological functioning was significantly poorer at baseline for the HIV-infected children as compared with established norms for their age. Children with higher viral load had poorer cognitive, both-hands fine-motor, and neurologic signs at baseline, but single-hand fine-motor and behavioral functioning were not correlated with viral load. After 48 weeks of treatment with PI-containing combination therapy, there was significant improvement in only the vocabulary score. Neuropsychological changes did not differ among the 6 PI-containing combination regimens. At week 48, even children with a viral load response below the level of detection (RNA < or =400 copies/mL) still showed poorer neuropsychological functioning compared with established norms.

CONCLUSION

Poor neuropsychological functioning was seen for HIV-infected children and was worse for children with higher viral loads. Only 1 measure of neuropsychological functioning showed improvement after treatment with PI-containing combination therapy, and the extent of that improvement was relatively minor. Treatment strategies for children with HIV disease need to be reevaluated so that they consider restoration of neuropsychological functioning in addition to lowering the viral load.

Cognitive decline with immunologic and virologic stability in four children with human immunodeficiency virus disease

This case series describes 4 children with vertically acquired human immunodeficiency virus (HIV) infection who exhibited immunologic, virologic, and clinical stability while on a protease inhibitor-containing highly active antiretroviral therapy (HAART) regimen, yet demonstrated significant cognitive decline as measured by standardized intelligence tests. A retrospective review of 107 patient records of children with HIV infection on HAART treatment protocols was conducted. Four patients were identified who responded to protease inhibitor-containing HAART therapy with sustained viral load suppression, and stable immunologic and medical parameters, yet demonstrated significant cognitive decline. Such discordance between biological and clinical markers previously has been reported in adults with HIV disease but not in children. This observed decline in neurocognitive functioning despite stable medical parameters suggests that HAART regimens that are effective for systemic disease may not be as effective for the central nervous system (CNS), perhaps because the antiretrovirals do not penetrate adequately into the CNS. Of note, 3 of these 4 patients did not have zidovudine (ZDV) included in their HAART regimen. The only patient who was treated with ZDV containing regimen received 90 mg/m(2) every 6 hours, which is at the lower end of the recommended ZDV pediatric full-dose range (90 mg/m(2) to 120 mg/m(2)). Two of the 4 patients began ZDV at 120 mg/m(2) every 6 hours following the decline in their cognitive test scores and subsequently showed improved or stable functioning as evidenced by the results of follow-up psychometric testing. Long-term prospective studies using both systemic and CNS measures are necessary to further investigate the effects of HAART in children with HIV disease. Longitudinal cognitive assessments of children receiving HAART appear indicated to identify cognitive decline and to provide appropriate therapeutic intervention when manifestations of HIV-related CNS disease progression occur.

Neurological and developmental effects of HIV and AIDS in children and adolescents

HIV-related encephalopathy is an important problem in vertically infected children with HIV. Infected infants may manifest early, catastrophic encephalopathy, with loss of brain growth, motor abnormalities, and cognitive dysfunction. Even without evidence of AIDS, infected infants score lower than serorevertors on developmental measures, particularly language acquisition. Children with perinatal or later transfusion-related infection generally are roughly comparable developmentally to their peers until late in their course. Symptoms similar to adult AIDS dementia complex are occasionally seen in adolescents with advanced AIDS, including dementia, bradykinesia, and spasticity. Opportunistic CNS infections such as toxoplasmosis and progressive multifocal leukoencephalopathy are less common in children and adolescents than in adults. Increasing evidence suggests that aggressive antiretroviral treatment may halt or even reverse encephalopathy. Neuroimaging changes may precede or follow clinical manifestations, and include early lenticulostriate vessel echogenicity on cranial ultrasound, calcifying microangiopathy on CT scan, and/or white matter lesions and central atrophy on MRI. Differential diagnosis of neurological dysfunction in an HIV-infected infant includes the effects of maternal substance abuse, other CNS congenital infections, and other causes of early static encephalopathy. Initial entry of HIV into the nervous system occurs very early in infection. The risk of clinical HIV encephalopathy increases with very early age of infection and with high viral loads. Virus is found in microglia and brain derived macrophages, not neurons. The neuronal effect of HIV is probably indirect, with various cytokines implicated. Apoptosis is the presumed mechanism of damage to neurons by HIV.

Neuroscience research in AIDS

1. The human immunodeficiency virus invades the central nervous system early after infection where it later gives rise to cognitive, motor, and behavioral manifestations in children and adults. 2. Ranging from mild impairments to frank dementia, CNS manifestations can be diagnosed and measured with standard neuropsychological test batteries. 3. Great strides have been made with treatment: CNS manifestations are treatable, as are depression, psychosis, and delirium which sometimes accompany HIV disease at different stages. 4. With startling advances in antiretroviral therapy and lower mortality, patients face a constellation of new concerns stemming from HIV's transformation to a more chronic disease. 5. There are many compelling research directions ahead, including the psychosocial impact of living with HIV as a chronic disease, the development of medications expressly targeted to the CNS, and basic research on neuropathogenesis, including trafficking of virus into the CNS.

Timing of perinatal human immunodeficiency virus type 1 infection and rate of neurodevelopment. The Women and Infant Transmission Study Group

BACKGROUND

Identifying HIV-1-infected children who are at greatest risk for disease-related morbidities is critical for optimal therapeutic as well as preventive care. Several factors have been implicated in HIV-1 disease onset and severity, including maternal and infant host characteristics, viral phenotype and timing of HIV-1 infection. Early HIV-1 culture positivity, i.e. intrauterine infection, has been associated with poor immunologic, virologic and clinical outcomes in children of HIV-infected women. However, a direct effect of timing of infection on neurodevelopmental outcome in infancy has not yet been identified.

METHODS

Serial neurodevelopmental assessments were performed with 114 infants vertically infected with HIV-1 in a multicenter natural history, longitudinal study. Median mental and motor scores were compared at three time points. Longitudinal regression analyses were used to evaluate the neurodevelopmental functioning of children with early positive cultures and those with late positive cultures.

RESULTS

Early infected infants scored significantly lower than late infected infants by 24 months of age and beyond on both mental (P = 0.05) and motor (P = 0.03) measures. Early HIV-1 infection was associated with a decline in estimated motor scores of 1 standard score point per month compared with 0.28 point in the late infected group (P < 0.02). Estimated mental scores of the early infected group declined 0.72 point/ month, whereas the average decline of the late infected group was 0.30 point/month (P < 0.13).

CONCLUSION

Early HIV-1 infection increases a child's risk for poor neurodevelopmental functioning within the first 30 months of life.

Nutritional Contributions to the CNS Pathophysiology of HIV-1 Infection and Implications for Treatment

Nutritional deficiencies are commonplace in patients with human immunodeficiency virus type 1 (HIV-1) infection, and recent research has indicated that nutritional factors may play an important role in the pathogenesis of HIV-1 disease. Although nutritional deficiencies are unlikely to be the primary causative factor in disease progression, they may contribute to cognitive dysfunction, neurologic abnormalities, mood disturbance, and immune dysregulation associated with HIV-1 infection. Furthermore, deficiencies of specific micronutrients have been associated with increased risk of HIV-1-associated mortality. This article will briefly summarize the role of macronutrient deficiency, the interactions of specific micronutrient deficiencies with neuropsychiatric functioning, and the role of these factors in HIV-1 disease progression. Since recent research has shown that normalization of many nutritional deficits and supplementation beyond normal levels are associated with improvements in neuropsychiatric functioning, potential treatment implications will also be discussed.

Neurologic, neurocognitive, and brain growth outcomes in human immunodeficiency virus-infected children receiving different nucleoside antiretroviral regimens. Pediatric AIDS Clinical Trials Group 152 Study Team

OBJECTIVES

To compare the impact of three different nucleoside reverse transcriptase inhibitor regimens, zidovudine (ZDV) monotherapy, didanosine (ddI) monotherapy, and ZDV plus ddI combination therapy, on central nervous system (CNS) outcomes in symptomatic human immunodeficiency virus (HIV)-infected children.

METHODS

Serial neurologic examinations, neurocognitive tests, and brain growth assessments (head circumference measurements and head computed tomography or magnetic resonance imaging studies) were performed in 831 infants and children who participated in a randomized double-blind clinical trial of nucleoside reverse transcriptase inhibitors. The Pediatric AIDS Clinical Trials Group study 152 conducted between 1991 and 1995 enrolled antiretroviral therapy-naive children. Subjects were stratified by age (3 to <30 months of age or 30 months to 18 years of age) and randomized in equal proportions to the three treatment groups.

RESULTS

Combination ZDV and ddI therapy was superior to either ZDV or ddI monotherapy for most of the CNS outcomes evaluated. Treatment differences were observed within both age strata. ZDV monotherapy showed a modest statistically significant improvement in cognitive performance compared with ddI monotherapy during the initial 24 weeks, but for subsequent protection against CNS deterioration no clear difference was observed between the two monotherapy arms.

CONCLUSIONS

Combination therapy with ZDV and ddI was more effective than either of the two monotherapies against CNS manifestations of human immunodeficiency virus disease. The results of this study did not indicate a long-term beneficial effect for ZDV monotherapy compared with ddI monotherapy.

New Thoughts on Pathogenesis and Diagnosis of Encephalitis

Knowledge regarding the pathogenesis of viral encephalitis, defined as inflammation and destruction of the central nervous system (CNS) from viral infection and the resulting immune response, has improved with advances in molecular biology techniques and recent advances in immunology and neuroscience research. An increasingly complex understanding has developed with regard to viral CNS infection. In addition to advances in viral genetics exploring increased viral spread and neurovirulence, improved understanding from research on neurochemistry, neurodevelopment, and cytokine expression in the CNS has led to new hypotheses regarding the mechanism of CNS damage during viral CNS infection. This review explores three advances in the understanding of viral encephalitis in the past few years: 1) the relationship between viral load and extent of viral CNS disease, 2) chemokines and their role in the CNS inflammatory response as well as in the pathogenesis of encephalitis, and 3) secondary damage from the release of neurotoxins during encephalitis. By examining this research, the reviewers intend to introduce novel therapeutic modalities that are developing for the management of patients with viral encephalitis beyond the timely use of antiviral therapy.

Early language development in children exposed to or infected with human immunodeficiency virus

OBJECTIVES

To compare language development in infants and young children with human immunodeficiency virus (HIV) infection to language development in children who had been exposed to HIV but were uninfected, and (among subjects with HIV infection) to compare language development with cognitive and neurologic status.

DESIGN

Prospective evaluation of language development in infected and in exposed but uninfected infants and young children.

SETTING

Pediatric Infectious Disease Clinic, State University of New York-Health Science Center at Syracuse.

SUBJECTS

Nine infants and young children infected with HIV and 69 seropositive but uninfected infants and children, age 6 weeks to 45 months.

RESULTS

Mean Early Language Milestone Scale, 2nd edition (ELM-2) Global Language scores were significantly lower for subjects with HIV infection, compared with uninfected subjects (89.3 vs 96.2, Mann-Whitney U test). The proportion of subjects scoring >2 SD below the mean on the ELM-2 on at least one occasion also was significantly greater for subjects with HIV infection, compared with uninfected subjects (4 of 9 infected subjects, but only 5 of 69 uninfected subjects; Fisher's exact test). Seven of the 9 subjects with HIV infection manifested deterioration of language function. Four manifested unremitting deterioration; only 1 of these 4 demonstrated unequivocal abnormality on neurologic examination. Three subjects with HIV infection and language deterioration showed improvement in language almost immediately after the initiation of antiretroviral drug treatment. Magnetic resonance imaging or computed tomography of the brain were performed in 6 of 7 infected subjects with language deterioration, and findings were normal in all 6. ELM-2 Global Language scaled scores showed good agreement with the Bayley Mental Developmental Index or the McCarthy Global Cognitive Index (r = 0. 70). Language deterioration, or improvement in language after initiation of drug therapy, coincided with or preceded changes in global cognitive function, at times by intervals of up to 12 months.

CONCLUSIONS

Language deterioration occurs commonly in infants and young children with HIV infection, is seen frequently in the absence of abnormalities on neurologic examination or central nervous system imaging, and may precede evidence of deterioration in global cognitive ability. Periodic assessment of language development should be added to the developmental monitoring of infants and young children with HIV infection as a means of monitoring disease progression and the efficacy of drug treatment.

Neurodevelopmental/neuroradiologic recovery of a child infected with HIV after treatment with combination antiretroviral therapy using the HIV-specific protease inhibitor ritonavir

BACKGROUND

Neurodevelopmental impairment has been identified in children infected with human immunodeficiency virus (HIV). The frequency and spectrum of neurologic impairment are greater in children than those reported for adults. In children, HIV is known to enter the central nervous system early in the course of the disease. The presentation of pediatric neuro-acquired immune deficiency syndrome ranges from static (eg, nonprogressive developmental delay) to progressive encephalopathy (eg, acquired microcephaly, pyramidal tract signs, and spasticity). It has been demonstrated that antiretroviral agents can improve or even reverse the course of neurologic impairment in children. These changes have been attributed to various degrees of central nervous system drug penetration. Increasingly, protease inhibitors and combination antiretroviral therapy using reverse transcriptase inhibitors are being used in the treatment of children infected with HIV. The addition of a protease inhibitor to nucleoside analogue therapy has been reported to delay disease progression and prolong life in adults with moderate to advanced HIV disease. No data currently exist on the impact of combination therapy using two nucleoside analogues and a protease inhibitor on neurodevelopmental and neurologic function in children with HIV infection. The following case report presents the effects of combination therapy using ritonavir in a child infected with HIV.

CASE REPORT

An 8-year, 2-month-old African-American boy was infected with HIV through vertical transmission. Regular monitoring of the patient's neurodevelopmental status has been conducted as part of his participation in longitudinal research protocols. For the first 51/2 years of life, his neurodevelopmental status was normal, with cognitive functioning as measured by standardized psychometric tools solidly in the average range. Speech and language skills were age-appropriate. Tests of gross and fine motor functioning as well as evaluation of overall neurodevelopmental status suggested normal development. Magnetic resonance imaging (MRI) of the brain was consistently normal. His family reported that adaptive functioning, peer and family relationships, and behavior were all within normal limits. School reports indicated consistently that the patient was performing at age and grade level, with respect to both academic achievement and behavior. Initial concerns regarding the patient's development were expressed by both his family and school at age 6 years, 6 months. These concerns included difficulty with classroom work, decreased attention, word-finding problems, fatigue, staring spells, and loss of strength. His family and school reported a marked loss of skills acquired previously. Results of formal psychological and speech and language evaluation reflected statistically significant drops in test scores from baseline, with both delayed and atypical skills evident. The patient's condition worsened rapidly. Within a few months, he was no longer able to use sentences to communicate. Cognitive testing was attempted, but he was unable to participate because of significant fatigue, limited attention, and inability to communicate verbally. His family described periods of disorientation and confusion, lethargy, and disinterest in age-appropriate activities. He became agitated and overstimulated easily both in small group settings and in crowds. He demonstrated both fine and gross motor impairments. When frustrated, he displayed infantile and autistic-like behavior. MRI with contrast showed diffuse atrophy as well as mild prominence of the ventricles and sulcii compared with baseline assessment. In addition to fatigue and neurologic symptoms, wasting syndrome was diagnosed, with loss of percentiles in both weight and height by age 71/2 years. Low-grade elevation of liver function tests and amylase was noted. Blood cultures for mycobacteria were negative, as were serologic tests for hepatitis. (ABSTRACT TRUN

Receptive and expressive language function of children with symptomatic HIV infection and relationship with disease parameters: a longitudinal 24-month follow-up study

OBJECTIVES

To longitudinally assess the receptive and expressive language functioning of children with symptomatic HIV disease and to explore the relationship between immune status, computed tomography (CT) brain scan abnormalities, and language dysfunction over time.

METHODS

Children with symptomatic HIV infection were administered an age-appropriate standardized comprehensive language test and general cognitive measure prior to starting antiretroviral therapy (n = 44) and again after 6 months (n = 29) and 24 months (n = 17). CD4 percentage and CT brain scans were also obtained at each evaluation.

RESULTS

Expressive language was significantly more impaired than receptive language at the baseline, 6- and 24-month evaluations. No significant changes over time were found in receptive or expressive language from baseline to after 6 months of antiretroviral therapy, but despite treatment, language scores declined significantly between 6 and 24 months. Overall cognitive function, however, remained stable from baseline to 24 months. Age-adjusted CD4 percentage increased significantly over the initial 6 months, then remained stable. Overall CT brain scan severity ratings did not change significantly over 24 months.

CONCLUSION

Expressive language was consistently more impaired than receptive language over 24 months, further supporting an earlier finding that expressive language was differentially affected by HIV in children with symptomatic disease. Both receptive and expressive language declined significantly after 24 months despite antiretroviral therapy, although overall cognitive function remained stable. Thus, functioning in some domains may be more vulnerable to the effects of HIV and global measures of cognitive ability may mask such differential changes in specific brain functions.

Pharmacotherapy of HIV dementia

OBJECTIVE

To review the clinical presentation and management of cognitive impairment associated with central nervous system HIV type 1 (HIV-1) infection.

DATA SOURCES

A MEDLINE search pertaining to HIV-related dementia (HIV-D) and pharmacologic management was performed. Additional literature was obtained from reference lists of the identified articles.

STUDY SELECTION AND DATA EXTRACTION

All clinical trials and case reports evaluating pharmacologic efficacy in terms of clinical response, cerebrospinal fluid (CSF) changes, and neuropathology were considered for inclusion. Selection was not restricted by study design because most information consists of open uncontrolled trials and case reports.

DATA SYNTHESIS

HIV-D is characterized by a triad of disturbances in cognition, motor performance, and behavior in adults. Children present with developmental delay, cognitive impairment, poor brain growth, and other neurologic symptoms. The exact pathophysiologic mechanisms of HIV-D are not known. Numerous pharmacologic agents (e.g., nucleoside reverse transcriptase inhibitors, pentoxifylline, nitroglycerin, memantine, nimodipine, peptide T) are under investigation for management of HIV-D. Zidovudine is the most thoroughly investigated medication, with patients developing HIV-D less frequently and showing improvement on neuropsychological, CSF, and neuropathologic evaluations. Sustained response to zidovudine lasts 6 months to 1 year and optimal response is achieved at higher, but less tolerated, dosages. HIV-D patients frequently have comorbid psychiatric disorders requiring psychopharmacologic agents and are sensitive to the adverse effects of these medications.

CONCLUSIONS

HIV-D is a devastating complication of HIV-1 infection. Zidovudine is the therapy of choice for prevention and management of cognitive impairment in symptomatic HIV-infected patients and patients with AIDS. Recommendations for other medications cannot be made secondary to lack of data. The management of HIV-D may include multiple agents as more data become available regarding combination therapy. Well-designed controlled trials are needed to evaluate the efficacy of established treatments and investigational medications in the management of HIV-D.

Vertical human immunodeficiency virus-1 infection: involvement of the central nervous system and treatment

Involvement of the central nervous system (CNS) contributes substantially to morbidity and mortality of vertical infection with the human immunodeficiency virus (HIV)-1. The clinical spectrum ranges from minor developmental disabilities to severe and progressive encephalopathy. Progression of the disease varies considerably. Both direct viral and indirect host-related pathogenic mechanisms have been proposed. The diagnosis depends on neurological and neurodevelopmental assessments. So far, HIV-1-specific antiviral treatment has shown limited effects on neurological manifestations in symptomatic children. Thus, efforts are needed to improve prevention and treatment of CNS involvement. It is still unclear whether early use of antiretroviral agents is of benefit.

CONCLUSION

Since experience of treatment of HIV-1 infections in adults cannot easily be translated to children, paediatric clinical trials are needed to answer questions specific to the unique characteristics of children.

A novel approach to the determination and characterization of HIV dementia

BACKGROUND

Neuropsychological studies of the pattern and extent of cognitive impairment in HIV-infected patients have mostly used deviations from control values and/or cut-off scores as criteria for classification of dementia. There is, however, no agreement as to how to define impairment, and classification is imprecise.

METHOD

The current study used a dementia classification matrix, developed with a step-wise linear discriminant analysis of neuropsychological data from patients with primary neurodegenerative dementias, to classify symptomatic HIV patients as demented or non-demented, and further to differentiate cortical and subcortical dementia patterns. Thirty-two male and 2 female patients (mean age 39 +/- 2) with symptomatic HIV disease (mean absolute CD4 count 195 +/- 41) participated in the study.

RESULTS

Thirty-five per cent of patients were classified as demented. Of these, 83% showed a subcortical pattern and 17% a cortical profile of deficits. Significant differences between patients classified as subcortically demented and those categorized as normal on neuropsychological measures associated with subcortical integrity further validated the classification. Measures of psychiatric status between subgroups were similar.

CONCLUSION

Since certain treatments may delay or reverse cognitive deficits, the use of an objective classification method based on discriminant analysis may help to identify patients who may benefit from therapy.

Interrelations among patterns of change in neurocognitive, CT brain imaging and CD4 measures associated with anti-retroviral therapy in children with symptomatic HIV infection

The interrelationships of patterns of change and variability between baseline and after 6 months of anti-retroviral therapy in neurocognitive, brain imaging, and immune measures were studied in 77 children with symptomatic HIV disease. Overall improvement in CNS structure/function after 6 months of anti-retroviral therapy was limited; new intracerebral calcifications tended to occur and old ones tended to progress in young children with vertically acquired HIV infection, despite treatment. Substantial inter-individual differences in change were however observed. Factors which explained part of the variance in the magnitude and direction of change were baseline structural and functional abnormalities, rating of degree of CNS penetration of the drug protocol, and concurrent changes on other variables. These preliminary data suggest that CNS specific effects of therapies as well as pretreatment status of CNS function/structure need to be taken into consideration when evaluating future trials of anti-retroviral therapy for children with symptomatic HIV infection.

Clinical comparison of adult and pediatric NeuroAIDS

Human Immunodeficiency Virus type-1 (HIV-1)-associated neurologic disease occurs as the initial presenting clinical manifestation of acquired immunodeficiency syndrome (AIDS) in 3-7% of infected patients, but in up to 18% of children and adolescents (Janssen, 1992; Janssen et al., 1992; Scott et al., 1989; Mintz et al., 1989a; Epstein et al., 1986). The overall prevalence of dementia in adult AIDS patients is 7.3-11.3% (Janssen, 1992), but up to 30-60% of children with AIDS manifest an analogous progressive encephalopathy (Epstein et al., 1986; Belman et al., 1988; Mintz, 1992; The European Collaborative Study, 1990). As a result of both direct and indirect effects of HIV-1 infection of the central nervous system (CNS), a distinct clinical and pathologic picture has emerged of insidious and severe neurologic deterioration, termed "AIDS Dementia Complex" (ADC) in adults, and "HIV-1-associated Progressive Encephalopathy" (PE) in children (Working Group, 1991) (see Table 1). In the severe manifestations of this pariah, there is little dispute as to the necessity of CNS HIV-1 infection for precipitating the cascade of adverse neurologic symptoms, although the pathogenic mechanisms of neurologic dysfunction and destruction--whether a result of direct cellular infection of HIV, secondarily produced and upregulated cytotoxic cytokines, or co-infection with opportunistic pathogens--remains an area of active research (Epstein and Gendelman, 1993; Fiala et al., 1993; Wiley and Nelson, 1988; Saito et al., 1994; Koenig et al., 1986; Sharer, 1992). Furthermore, the existence of systemic immune deficiency renders the CNS susceptible to opportunistic infection (OI), particularly in adult patients, adding further to morbidity and mortality (Clifford and Campbell, 1992). With the introduction of antiretroviral nucleoside analogues, there have been reports of a decreasing incidence of ADC (Portegies et al., 1989; Day et al., 1992), and amelioration--at least temporarily--of PE in children (Pizzo et al., 1988; Mintz and Epstein, 1992; Brouwers et al., 1990; Mintz et al., 1990). This appends further evidence to the central precipitating role of CNS HIV-1 infection.

Neurologic syndromes

It is now well recognized that HIV-1 associated CNS disease may complicate the course of HIV-1 infection and AIDS in infants and children. It is also well recognized that the neurologic dysfunction in these young patients adds significantly to the morbidity of the disease and is often a devastating complication. It is apparent that HIV-1 CNS infection in infants and young children is complicated by numerous developmental issues. The effects, direct and indirect, of HIV-1 on the developing nervous system must be considered. The effects of HIV-1 on the immature immune system must also be considered. Moreover, the possible effects of HIV-1 on the many complex interactions between these two systems during development will clearly also require investigation. In order to care for these children and to design rational approaches for treatment and prevention, it is now critical to develop a better understanding of how HIV-1 affects the developing nervous system.

Zidovudine. An update of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Zidovudine remains the mainstay in the treatment of patients infected with human immunodeficiency virus (HIV). The drug delays disease progression to acquired immunodeficiency syndrome (AIDS) and to AIDS-related complex (ARC), reduces opportunistic infections, and increases survival in patients with advanced HIV infection. There is evidence to suggest that zidovudine also delays disease progression in patients with mild symptomatic disease. Although one study has shown zidovudine to have no significant beneficial effects on survival or disease progression in patients with asymptomatic HIV infection, several other studies have shown zidovudine to delay disease progression in this patient group. Results from related ongoing studies are awaited with interest. Zidovudine reduces the incidence of AIDS dementia complex (ADC) and appears to prolong survival in these patients, and improves other neurological complications of HIV infection. The drug also appears to enhance the efficacy of interferon-alpha in patients with Kaposi's sarcoma. Although zidovudine is widely used as postexposure prophylaxis following accidental exposure to HIV, its efficacy in preventing seroconversion is unclear. Whether zidovudine prevents vertical transmission also remains to be determined. The overall efficacy of zidovudine in the treatment of children with HIV infection appears similar to that in adults despite more rapid disease progression in younger patients. Zidovudine-resistant isolates can emerge as early as after 2 months' therapy, and primary infection with zidovudine-resistant strains has been documented. Both zidovudine resistance and the syncytium-inducing HIV phenotype appear to be associated with poor clinical outcome. However, zidovudine resistance may revert on drug withdrawal or switching to an alternative therapy. Zidovudine-associated haematotoxicity may be dose-limiting. Nonhaematological adverse events associated with zidovudine therapy are generally mild and usually resolve spontaneously. Dosages of approximately 500 to 600 mg/day appear to be at least as effective as dosages of 1200 to 1500 mg/day and are better tolerated in patients with less advanced disease. However, optimal dosage are unclear. Despite beneficial effects, zidovudine monotherapy is not curative. There is evidence to suggest that the concomitant administration of zidovudine with didanosine or zalcitabine is effective in patients with HIV disease progression despite receiving zidovudine monotherapy, and there is some evidence that concomitant zidovudine plus didanosine therapy is more effective than alternating monotherapy. However, results from studies of combination therapy in asymptomatic patients, and from comparative combination therapy studies are awaited. Cotherapy with agents that augment haematopoiesis allows the continuation of therapeutic zidovudine dosages.(ABSTRACT TRUNCATED AT 400 WORDS)

A screening test for subtle cognitive impairment early in the course of HIV infection

The authors report on the use of the Rey-Osterrieth Complex Figure Copy (ROC) and Memory (ROM) test as a bedside screening measure of cognitive impairment in 67 HIV-seropositive persons (43 men, 24 women). HIV-seropositive individuals scored significantly worse than 49 HIV-seronegative matched individuals (33 men, 16 women) in the control group on the ROC (P = 0.045, effect size = 0.39), but not on the ROM test. The scores did not correlate with stage of HIV infection, CD4a cell counts, cerebrospinal fluid parameters, or measures of affective state. No gender effects on performance were noted. It is concluded that while cognitive deficits may occur early in asymptomatic HIV disease, the ROC/ROM test as the authors used it is not a useful screening tool for clinicians. The study also suggests that the growing number of HIV-positive women should be included in neuropsychological studies of early HIV disease.

Pediatric AIDS: a longitudinal comparative MRI and CT brain imaging study

Fourteen consecutive children with acquired immune deficiency syndrome (AIDS) (age range, 4 months to 11 years; median 4 years) were studied prospectively comparing nonenhanced cranial magnetic resonance imaging (MRI) and computed tomographic (CT) scans. MRI and CT were performed twice: at time of entry into protocol and again at 1 year. In addition, sequential neurologic (every 2 months) and neuropsychological examinations (every 6 months) were performed. At entry, 12 children had abnormal neurologic examinations; of these, 10 had developmental delay; two children were normal by developmental history and neurologic examination. Five children performed in the normal range on a standardized neuropsychological test, whereas nine children showed significant delays in verbal or motor/perceptual development. Following 1 year of study, four children had normal and six had abnormal neurologic examinations (six stable and four improved). Neuropsychological examinations were normal in five children and abnormal in five (seven stable, one improved, and two deteriorated). At entry, the following neuroradiographic abnormalities were seen: brain parenchymal volume loss (eight, MR = CT), cervical lymphatic enlargement (four, MR = CT), striatal-thalamic calcification (one, CT > MR), delayed myelination (one, MR > CT), and focal white-matter lesions (one, MR > CT). At 1 year the following neuroradiographic changes were seen: brain parenchymal volume loss (10, MR = CT; two improved, eight stable); cervical lymphatic enlargement (one, MR = CT; three improved, one stable), striatal-thalamic calcification (one, CT > MR; one new), and focal white-matter lesions (one, MR > CT; one stable).(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid serologic testing with immune-complex-dissociated HIV p24 antigen for early detection of HIV infection in neonates. Southern California Pediatric AIDS Consortium

BACKGROUND

Serologic detection of human immunodeficiency virus (HIV) infection in neonates is complicated by the presence of immune complexes, consisting of passively transferred maternal antibodies and HIV antigens. A new, rapid assay has been designed to disrupt these immune complexes in order to permit the detection of a specific HIV antigen. We evaluated the efficacy of this assay in detecting HIV infection in neonates.

METHODS

We measured p24 antigen in blood samples from both infected and uninfected children of HIV-infected mothers. The samples were treated with glycine hydrochloride to dissociate the immune complexes, followed by neutralization with TRIS-hydrochloric acid. A commercial HIV p24 antigen assay was then used, with an optical density greater than 0.120 at a wavelength of 450 nm defined as indicating a positive result.

RESULTS

Of eight cord-blood samples from neonates with proved HIV infection, five were positive for immune-complex-dissociated p24 antigen. For two other neonates the first postnatal sample, obtained on days 12 and 18, was positive. There was no follow-up sample for the eighth neonate. Of 22 uninfected neonates, 20 were negative on the cord-blood assay. Two neonates had positive cord-blood samples, but the first postnatal sample was negative. Thus, the tests with early postnatal samples identified the HIV-infection status correctly for all 29 children who could be evaluated. In a separate group of 78 children (median age, 188 weeks), the specificity of the test was 100 percent and the sensitivity 81 percent.

CONCLUSIONS

The immune-complex-dissociated HIV p24 antigen assay is a rapid, simple serologic test that may be of value in diagnosing HIV infection in neonates born to HIV-infected women.

Phase I evaluation of zidovudine administered to infants exposed at birth to the human immunodeficiency virus

This study evaluated the safety, tolerability, and pharmacokinetics of zidovudine administered intravenously and orally to infants born to women infected with the human immunodeficiency virus. Thirty-two symptom-free infants were enrolled before 3 months of age. The pharmacokinetics of zidovudine were evaluated in each infant after single intravenously and orally administered doses of zidovudine on consecutive days, and during long-term oral administration of the drug for 4 to 6 weeks. As new patients were enrolled, doses of zidovudine were progressively increased from 2 to 4 mg/kg. Therapy was continued for up to 12 months in 7 of the infants proved to be infected with human immunodeficiency virus. Zidovudine was generally well tolerated; 20 children (62.5%) had anemia (hemoglobin level < 10.0 gm/dl) during therapy and 9 (28.1%) had neutropenia (neutrophil count < or = 750 cells/mm3); these hematologic abnormalities usually resolved spontaneously. The total body clearance of zidovudine increased significantly with age, from an average of 10.9 ml/min per kilogram in infants < or = 14 days of age to 19.0 ml/min per kilogram in older infants (p < 0.0001). Concurrently, there was a significant decrease in serum half-life from 3.12 hours in infants < or = 14 days to 1.87 hours in older infants (p = 0.0002). Oral absorption was satisfactory and bioavailability decreased significantly with age, from 89% in infants < or = 14 days to 61% in those > 14 days of age (p = 0.0002). Plasma concentrations of zidovudine were calculated to be in excess of 1 mumol/L (0.267 micrograms/ml) for 4.12 +/- 1.86 hours and 2.25 +/- 0.78 hours after oral doses of 2 mg/kg in infants younger than 2 weeks and 3 mg/kg in older infants, respectively. We conclude that zidovudine administered at oral doses of 2 mg/kg every 6 hours to infants aged less than 2 weeks and 3 mg/kg every 6 hours to infants older than 2 weeks resulted in plasma concentrations that are considered virustatic against human immunodeficiency virus. Zidovudine was well tolerated by infants at these doses.

Zidovudine therapy in combination with intravenous immunoglobulin in HIV infected children

There is little published data on concomitant use of zidovudine and intravenous immunoglobulin (IV IgG). In this paper we review our experience of four HIV-1 infected children treated with zidovudine for periods of 19-33 months (mean 26.5 months) subsequent to starting IV IgG for period of 18-20 months (mean 19 months). In these children the only clear benefit we found was in one child who had developed HIV encephalopathy which resolved after starting zidovudine. The respective roles of zidovudine and intravenous immunoglobulin in HIV-1 infected children need to be clarified in larger comparative trials.

Acquired immunodeficiency syndrome and the child's central nervous system

Human immunodeficiency virus-1 (HIV-1) associated central nervous system disease may complicate the course of HIV-1 infection in infants and children. Neurologic dysfunction in these young patients adds significantly to the morbidity of the disease and is often a devastating complication. It is apparent that HIV-1 infection in infants and young children is complicated by numerous developmental parameters. The developmental stage of the nervous and immune systems when exposed to the virus is likely to interact in complex ways with HIV-1 variables. In order to care for these children and to design rational approaches for treatment and prevention, it is now critical to develop a better understanding of how HIV-1 affects the developing nervous system.

Clinical manifestations, management and therapy of HIV infection in children

Perinatal infection accounts for the majority of cases of HIV infection in children both in developed and developing countries. Transmission may occur in utero, intrapartum or postpartum as a result of breast-feeding. The actual risk of transmission through breast-feeding is unknown. The majority of infants reported to be infected through breast milk have been infected as a result of a recently acquired HIV infection in the mother. Infants with HIV infection frequently present with clinical symptoms early in life. There is a broad spectrum of clinical findings in paediatric HIV infection, with opportunistic infections and multiorgan system involvement being common. The management of infants born to seropositive mothers includes routine paediatric care as well as careful clinical and laboratory monitoring for evidence of HIV infection. Infants who are seronegative with normal clinical and immunological findings at 18 months of age are considered uninfected. The prognosis and outcome of infants with HIV infection have improved considerably with earlier diagnosis and the availability of specific antiviral therapy. Modalities of therapy include frequent medical evaluation, aggressive diagnosis and treatment of infection, prophylaxis for Pneumocystis carinii infection, the use of intravenous gamma-globulin and specific antiviral therapy, such as zidovudine, didanosine or other drugs in development through clinical trials. HIV infection in children is a chronic illness and requires a comprehensive, family-oriented approach to care. With longer survival, children require support systems and an atmosphere of care and understanding to give them a good quality of life as well as prolonged survival.