Pharmacokinetics and anticonvulsant effects of diazepam in children with severe falciparum malaria and convulsions

AIMS: Convulsions are a common complication of severe malaria in children and are associated with poor outcome. Diazepam is used to terminate convulsions but its pharmacokinetics and pharmacodynamics have not been studied in this group. Accordingly, we carried out a comparative study of the pharmacokinetics of intravenous (i.v.) and rectal (p.r.) diazepam. METHODS: Twenty-five children with severe malaria and a convulsion lasting >5 min were studied. Sixteen children received diazepam intravenously (i.v.; 0.3 mg kg(-1)) and nine rectally (p.r.; 0.5 mg kg(-1)). Plasma diazepam concentrations were measured by reversed phase high-performance liquid chromatography. The duration of convulsions, depth of coma, respiratory and cardiovascular parameters were monitored. RESULTS: Median maximum plasma diazepam concentrations of 634 (range 402-1507) ng ml(-1) and 423 (range 112-1953) ng ml(-1) were achieved at 5 and 25 min following i.v. and p.r. administration, respectively. All patients except three (one i.v. and two p.r.) achieved plasma diazepam concentration >200 ng ml(-1) within 5 min. Following p.r. administration, plasma diazepam concentrations were more variable than i.v. administration. A single dose of i.v. diazepam terminated convulsions in all children but in only 6/9 after p.r. administration. However, nine children treated with i.v. and all those treated with p.r. diazepam had a recurrence of convulsions occurring at median plasma diazepam concentrations of 157 (range: 67-169) and 172 (range: 74-393) ng ml(-1) , respectively. All the children in the i.v. and four in the PR diazepam group who had recurrence of convulsions required treatment. None of the children developed respiratory depression or hypotension. CONCLUSIONS: Administration of diazepam i.v. or p.r. resulted in achievement of therapeutic concentrations of diazepam rapidly, without significant cardio-respiratory adverse effects. However, following p.r. administration, diazepam did not terminate all convulsions and plasma drug concentrations were more variable.     

Developmental disorders in embryos of the frog Xenopus laevis induced by chloroacetanilide herbicides and their degradation products

Pesticides are known to transform in the environment, but so far the study of their effects in the environment has concentrated on the parent compounds, thereby neglecting the effects of the degradation products. The embryotoxic, developmental, and teratogenic effects of chloroacetanilide herbicides and their environmentally stable aniline degradation products were investigated in this study in view of the massive application of alachlor and metolachlor. Embryos at midblastula to early gastrula stages of a locally abundant African clawed frog Xenopus laevis were used as test organisms. The embryos were exposed to the test chemicals for 96 h in each experiment. Alachlor is more embryotoxic (the concentration causing 50% embryo lethality, 96-h LC50 = 23 microM [6.1 mg/L]) and teratogenic (teratogenic index [TI] = 1.7) than metolachlor (96-h LC50 = 48 microM [13.6 mg/L], TI = 0.2). The degradation products of alachlor and metolachlor, respectively, 2,6-diethylaniline (96-h LC50 = 13 microM [19.4 mg/L], TI = 2.1) and 2-ethyl-6-methyaniline (96-h LC50 = 509 microM [68.8 mg/L], TI = 2.7), are less embryotoxic but more teratogenic than their parent compounds. The most common teratogenic effects observed were edema for alachlor as opposed to axial flexures and eye abnormalities for 2,6-diethylaniline and 2-ethyl-6-methylaniline. Metolachlor is found to be an example of a nonteratogenic herbicide that upon degradation loses toxicity but gains teratogenicity, and both the herbicides, metolachlor and alachlor, are potential sources of teratogenic transformation products.     

Hemozoin differentially regulates proinflammatory cytokine production in human immunodeficiency virus-seropositive and -seronegative women with placental malaria

Pregnant women are at an increased risk for malarial infection. Plasmodium falciparum accumulates in the placenta and is associated with dysregulated immune function and poor birth outcomes. Malarial pigment (hemozoin) also accumulates in the placenta and may modulate local immune function. In this study, the impact of hemozoin on cytokine production by intervillous blood mononuclear cells from malaria-infected placentas was investigated. There was a dose-dependent, suppressive effect of hemozoin on production of gamma interferon (IFN-gamma), with less of an effect on tumor necrosis factor alpha (TNF-alpha) and interleukin-10, in human immunodeficiency virus-seronegative (HIV(-)) women. In contrast, IFN-gamma and TNF-alpha production tended to increase in HIV-seropositive women with increasing hemozoin levels. Production patterns of cytokines, especially IFN-gamma in HIV(-) women, followed different trends as a function of parasite density and hemozoin level. The findings suggest that the influences of hemozoin accumulation and high-density parasitemia on placental cytokine production are not equivalent and may involve different mechanisms, all of which may operate differently in the context of HIV infection. Cytokine production dysregulated by accumulation of hemozoin or high-density parasitemia may induce pathology and impair protective immunity in HIV-infected and -uninfected women.     

Trauma in rural Kenya

Background: Trauma in Africa is an increasingly significant problem. The aims of this study were to document the epidemiology and clinical management of trauma in a rural Kenyan hospital and from this to highlight important areas for the medical training of doctors managing trauma in similar situations.

Methods: Prospective audit of 202 consecutive trauma patients admitted to Kijabe Hospital.

Results: The mean patient age was 31, 77% were males. The median Injury Severity Score (ISS) was nine. The median distance to hospital was 60 km, with a 9 h delay in presentation. Injury mechanisms included road traffic accidents 52%, fall 22%, assaults 13% and burns 6%. The main injuries were limb fractures, soft tissue injuries, head injury and haemo/pneumothorax. Common interventions included fracture management, wound debridement, chest drain insertion, blood transfusion and skin grafting. The overall mortality rate was 3.5%.

Conclusion: With appropriate resources and training, good trauma outcomes are possible. The importance of access to hospital care and orthopaedic training are highlighted.     

Increased prevalence of epilepsy associated with severe falciparum malaria in children

PURPOSE: Multiple, prolonged, generalized, or focal seizures are common in children with severe malaria, with or without coma. In other contexts, such seizures have been associated with the development of epilepsy. The relation between falciparum malaria and epilepsy is undetermined; thus we measured the prevalence and characteristics of epilepsy in children with a history of severe malaria. METHODS: We took a detailed epilepsy history from the parents of 487 children (aged 6-9 years) to compare the prevalence of epilepsy between three exposure groups: children with a history of cerebral malaria (CM), malaria and complicated seizures (M/S), or those unexposed to either complication. Each child had an EEG and was classified as having active, inactive, or no epilepsy. RESULTS: An increased prevalence of epilepsy was seen in children previously admitted with CM [9.2%; OR, 4.4; 95% confidence interval (CI), 1.4-13.7] or M/S (11.5%; OR, 6.1; 95% CI, 2.0-18.3) compared with the unexposed group (2.2%). The most commonly reported seizure types were tonic-clonic (42%), focal becoming secondarily generalized (16%), and both (21%). Twenty-six percent of the active epilepsy group initially had EEG abnormalities. CONCLUSIONS: These results suggest that children exposed to CM or M/S have an increased propensity for epilepsy relative to children unexposed to these complications. The prevalence of epilepsy associated with CM is similar to that reported after other severe encephalopathies. The prevalence associated with M/S is more than twice that reported after complicated febrile seizures.     

Changing patterns of orphan care due to the HIV epidemic in western Kenya

The HIV/AIDS epidemic has given rise to major demographic changes including an alarming number of orphans in sub-Saharan Africa. The study describes a rural community in western Kenya in which one out of three children below 18 years of age had lost at least one biological parent-and one out of nine had lost both. The main problems these children faced were lack of school fees, food and access to medical care. The high number of orphans has overwhelmed the traditional mechanisms for orphan care, which were based on patrilineal kinship ties. Thus, 28% of the orphans were looked after by culturally "inappropriate" categories such as matrilineal kin or strangers. Furthermore, many of the caretakers were themselves not capable due to ill health or old age. Factors such as poverty, negative attitudes, and traditional funeral customs made the orphans' situation even worse. The authors conclude that though community-based interventions are urgently needed as the most appropriate way to address the issue, the complex, local reality in which cultural factors, kinship ties, and poverty are interwoven needs to be taken into consideration if sustainable solutions are to be found.     

Preventing mother-to-child transmission of HIV in Western Kenya: operational issues

OBJECTIVES: To improve uptake in a program to prevent mother-to-child HIV transmission and describe lessons relevant for prevention of mother-to-child transmission programs in resource-poor settings. METHODS: Implementation of a pilot project that evaluates approaches to increase program uptake at health facility level at New Nyanza Provincial General Hospital, a public hospital in western Kenya, an area with high HIV prevalence. Client flow was revised to integrate counseling, HIV testing, and dispensing of single-dose nevirapine into routine antenatal services. The number of facilities providing PMCT services was expanded to increase district-wide coverage. Main outcome measures were uptake of counseling, HIV testing, nevirapine, and estimated program impact. RESULTS: Uptake of counseling and testing improved from 55 to 68% (P < 0.001), nevirapine uptake from 57% to 70% (P < 0.001), and estimated program impact from 15% to 23% (P = 0.03). Aggregate reports compare well with computer-entered data. CONCLUSION: Addressing institutional factors can improve uptake, but expected program impact remains low for several reasons, including relatively low efficacy of the intervention and missed opportunities in the labor room.