Coma scales for children with severe falciparum malaria

Pharmacokinetics and clinical effects of phenytoin and fosphenytoin in children with severe malaria and status epilepticus

AIMS

Status epilepticus is common in children with severe falciparum malaria and is associated with poor outcome. Phenytoin is often used to control status epilepticus, but its water-soluble prodrug, fosphenytoin, may be more useful as it is easier to administer. We studied the pharmacokinetics and clinical effects of phenytoin and fosphenytoin sodium in children with severe falciparum malaria and status epilepticus.

METHODS

Children received intravenous (i.v.) phenytoin as a 18 mg kg-1 loading dose infused over 20 min followed by a 2.5 mg x kg(-1) 12 hourly maintenance dose infused over 5 min (n = 11), or i.v. fosphenytoin, administered at a rate of 50 mg x min(-1) phenytoin sodium equivalents (PE; n = 16), or intramuscular (i.m.) fosphenytoin as a 18 mg x kg(-1) loading dose followed by 2.5 mg x kg(-1) 12 hourly of PE (n = 11). Concentrations of phenytoin in plasma and cerebrospinal fluid (CSF), frequency of seizures, cardiovascular effects (respiratory rate, blood pressure, trancutaneous oxygen tension and level of consciousness) and middle cerebral artery (MCA) blood flow velocity were monitored.

RESULTS

After all routes of administration, a plasma unbound phenytoin concentration of more than 1 microg x ml(-1) was rapidly (within 5-20 min) attained. Mean (95% confidence interval) steady state free phenytoin concentrations were 2.1 (1.7, 2.4; i.v. phenytoin, n = 6), 1.5 (0.96, 2.1; i.v. fosphenytoin, n = 11) and 1.4 (0.5, 2.4; i.m. fosphenytoin, n = 6), and were not statistically different for the three routes of administration. Median times (range) to peak plasma phenytoin concentrations following the loading dose were 0.08 (0.08-0.17), 0.37 (0.33-0.67) and 0.38 (0.17-2.0) h for i.v. fosphenytoin, i.v. phenytoin and i.m. fosphenytoin, respectively. CSF: plasma phenytoin concentration ratio ranged from 0.12 to 0.53 (median = 0.28, n = 16). Status epilepticus was controlled in only 36% (4/11) following i.v. phenytoin, 44% (7/16), following i.v. fosphenytoin and 64% (7/11) following i.m. fosphenytoin administration, respectively. Cardiovascular parameters and MCA blood flow were not affected by phenytoin administration.

CONCLUSIONS

Phenytoin and fosphenytoin administration at the currently recommended doses achieve plasma unbound phenytoin concentrations within the therapeutic range with few cardiovascular effects. Administration of fosphenytoin i.v. or i.m. offers a practical and convenient alternative to i.v. phenytoin. However, the inadequate control of status epilepticus despite rapid achievement of therapeutic unbound phenytoin concentrations warrants further investigation.

[Treatment of children with malaria Plasmodium falciparum with derivatives artemisinin]

From January 1996 to December 1998, artemisinin derivatives were prescribed to 108 children infected with Plasmodium falciparum. The therapeutic effect was evaluated. Only children with moderate or severe malaria were included. Group I (intravenous artesunate; n = 62): 50.8% with moderate malaria and 49.2% with severe malaria; 53.2% with mild parasitemia, 22.6% with moderate parasitemia and 24.2% with high parasitemia; Group II (intramuscular artemether [Paluter ]; n = 46): 67.4% with moderate malaria and 32.6% with severe malaria; 52.2% with mild parasitemia, 36.2% with moderate parasitemia and 15.2% with high parasitemia; clinical amelioration and clearance of parasitemia showed no statistical difference between the groups. All patients cleared the parasitemia at the seventh day of follow-up (D7). In order to avoid recrudescence, mefloquine or clindamycin was used.

Acute bacterial meningitis in children admitted to a rural Kenyan hospital: increasing antibiotic resistance and outcome

BACKGROUND

Acute bacterial meningitis (ABM) is an important cause of mortality in Africa, but most studies are based in urban referral hospitals. Poor laboratory facilities make diagnosis difficult, and treatment is limited to inexpensive antibiotics.

METHODS

We retrospectively reviewed data from children admitted with ABM to a Kenyan district hospital from 1994 through 2000. We calculated the minimum incidence in children admitted from a defined area. We also examined the antibiotic susceptibility patterns.

RESULTS

We identified 390 cases (1.3% of all admissions) of whom 88% were <5 years old. The apparent minimum annual incidence in children younger than 5 years of age increased from 120 to 202 per 100,000 between 1995 and 2000 (P < 0.001). Increasing the lumbar punctures performed by including prostrated or convulsing children significantly increased the number of cases detected (P < 0.005). The most common organisms in infants <3 months were streptococci and Enterobacteriaceae. Streptococcus pneumoniae (43.1%) and Haemophilus influenzae (41.9%) were predominant in the postneonatal period. The overall mortality was 30.1%, and 23.5% of survivors developed neurologic sequelae. Chloramphenicol resistance of H. influenzae rose from 8% in 1994 to 80% in 2000 (P < 0.0001) accompanied by an apparent increase in mortality. A short history, impaired consciousness and hypoglycemia were associated with death. Prolonged coma and low cerebrospinal fluid glucose were associated with neurologic sequelae.

CONCLUSION

ABM in rural Kenya is a severe illness with substantial mortality and morbidity. Prognosis could be improved by broadening the criteria for lumbar puncture and use of appropriate antibiotics.

Inter-observer variation in the assessment of clinical signs in sick Tanzanian children

We assessed the inter-observer agreement in identification of a range of 24 clinical signs associated with disease presentation in 327 children aged < 5 years admitted to hospital in January-June 1999 in Ifakara, southern Tanzania. Children with diagnoses of malaria, pneumonia, diarrhoea, anaemia and malnutrition were examined independently by 2 clinical officers. Findings were recorded on a standard proforma. The Kappa-statistic was used to assess inter-observer agreement for each sign. Physical signs were more likely to be agreed upon by clinicians if they involved inspection than if they involved auscultation. The signs included in the Integrated Management of Childhood Illness (IMCI) algorithm were found to be largely appropriate (Kappa-scores > 0.41) although there was only fair agreement (Kappa-score 0.21-0.40) in the detection of neck stiffness and chest indrawing and slight agreement in the detection of dehydration (Kappa-score 0.199). All objective neurological signs were less reliably assessed in infants than in older children. The difficulties surrounding the diagnosis of impaired consciousness in young children should increase vigilance in the diagnosis and management of neurological complications of illnesses in infancy.

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.

Cerebral malaria

Cerebral malaria may be the most common non-traumatic encephalopathy in the world. The pathogenesis is heterogeneous and the neurological complications are often part of a multisystem dysfunction. The clinical presentation and pathophysiology differs between adults and children. Recent studies have elucidated the molecular mechanisms of pathogenesis and raised possible interventions. Antimalarial drugs, however, remain the only intervention that unequivocally affects outcome, although increasing resistance to the established antimalarial drugs is of grave concern. Artemisinin derivatives have made an impact on treatment, but other drugs may be required. With appropriate antimalarial drugs, the prognosis of cerebral malaria often depends on the management of other complications-for example, renal failure and acidosis. Neurological sequelae are increasingly recognised, but further research on the pathogenesis of coma and neurological damage is required to develop other ancillary treatments.

Neurological manifestations of falciparum malaria

Plasmodium falciparum remains one of the most common causes of central nervous system infection worldwide. Recently, differences between the pathophysiology of cerebral malaria in African children and nonimmune adults have been discovered, new syndromes occurring after malaria infection described, and mechanisms for the pathogenesis proposed. In addition, new antimalarial agents have been examined worldwide and initial studies on supportive studies conducted. This paper reviews these new advances, putting them into the perspective of the more established knowledge.