Madalitso Tembo

Dexamethasone treatment in childhood bacterial meningitis in Malawi: a randomised controlled trial

BACKGROUND Steroids are used as adjuvant treatment in childhood pyogenic meningitis to attenuate host inflammatory responses to bacterial invasion. We aimed to assess the effectiveness of dexamethasone in management of acute bacterial meningitis in a developing country. METHODS In a double-blind, placebo controlled trial, we included 598 children with pyogenic meningitis who had been admitted to the childrens wards of the Queen Elizabeth Central Hospital, Blantyre, Malawi. We did physical, neurological, developmental, and hearing assessments at 1 and 6 months after discharge. The primary outcome was overall death. Secondary outcomes included sequelae, in-hospital deaths, and death after discharge. Analysis was done by intention to treat. FINDINGS Of the 598 included children, 307 (51%) were assigned to dexamethasone and 295 (49%) to placebo. 338 (40%) of 598 patients had Streptococcus pneumoniae, 170 (28%) Haemophilus influenzae type b, 66 (11%) Neisseria meningitidis, and 29 (5%) Salmonella spp. 78 (13%) patients had no growth on culture. The number of overall deaths was the same in the two treatment groups (relative risk 1.00 [95% CI 0.8-1.25], p=0.93). At final outcome, sequelae were identified in 84 (28%) of children on steroids and in 81 (28%) on placebo (relative risk 0.99 [95% CI 0.78-1.27], p=0.97). The number of children dying in hospital did not differ between groups. INTERPRETATION Steroids are not an effective adjuvant treatment in children with acute bacterial meningitis in developing countries.

Bacteremia in Malawian Children with Severe Malaria: Prevalence, Etiology, HIV Coinfection, and Outcome

BACKGROUND Previous prospective studies of bacteremia in African children with severe malaria have mainly included children with cerebral malaria, and no study has examined the impact of human immunodeficiency virus (HIV) infection. We examined the prevalence and etiology of bacteremia and the impact of HIV infection on bacteremia in Malawian children with severe malaria, as well as the impact of bacteremia and HIV infection on outcome. METHODS From 1996 until 2005, blood for culture was obtained on admission from all children admitted with severe malaria during the rainy season to the Paediatric Research Ward at the Queen Elizabeth Central Hospital in Blantyre, Malawi. HIV testing was performed prospectively from 2001 to 2005 and retrospectively for those admitted from 1996 to 2000. Multivariate regression analysis examined independent risk factors for bacteremia and death. RESULTS Sixty-four (4.6%) of 1388 children with severe malaria had bacteremia; nontyphoidal Salmonellae (NTS) accounted for 58% of all bacteremias. The prevalence of any bacteremia and of NTS bacteremia was highest in children with severe malarial anemia (11.7% and 7.6%), compared with the prevalence in children with cerebral malaria and severe anemia (4.7% and 3.8%) and in those with cerebral malaria alone (3.0% and 0.9%). HIV infection status was determined in 1119 patients. HIV prevalence was 16% (and was highest in those with severe malaria anemia, at 20.4%), but HIV infection was not significantly associated with bacteremia. Neither bacteremia nor HIV infection was associated with death. CONCLUSIONS Antibiotics are not routinely indicated for children with severe malaria in this region, in which HIV is endemic. However, antibiotic therapy should be used to treat NTS infection if bacteremia is suspected in children with severe malarial anemia.

Cytokine Expression in the Brain in Human Cerebral Malaria

Evidence from clinical studies and murine models supports a role for cytokines in the pathogenesis of human cerebral malaria (CM). In this study, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate expression of mRNA for transforming growth factor (TGF)-beta, interleukin (IL)-1beta, and tumor necrosis factor (TNF)-alpha in human postmortem tissue. Immunohistochemistry was used to examine the distribution of cytokine protein. TGF-beta was expressed in normal brain, in CM, and in meningitis and encephalitis. IL-1beta was absent from normal brain but was detected in CM and other cerebral infections. TNF-alpha mRNA was expressed only in CM, although TNF-alpha protein was also seen in meningitis. Cytokine mRNA expression in the brain did not correlate with the density of parasitized erythrocytes detected using RT-PCR for major surface protein-2. This report of RT-PCR on postmortem human tissues infected with CM demonstrates induction of the proinflammatory cytokines TNF-alpha and IL-1beta in the brain.

Immune mimicry in malaria: Plasmodium falciparum secretes a functional histamine-releasing factor homolog in vitro and in vivo

The Plasmodium falciparum translationally controlled tumor protein (TCTP) is a homolog of the mammalian histamine-releasing factor (HRF), which causes histamine release from human basophils and IL-8 secretion from eosinophils. Histamine, IL-8, and eosinophils have been reported to be elevated in patients with malaria. This study was undertaken to determine whether malarial TCTP is found in the plasma of malaria-infected patients and to determine whether it has HRF biologic activity. Malarial TCTP was found in lightly infected human volunteers and in heavily infected Malawian children, but not in uninfected patients. Recombinant malarial TCTP, like HRF, stimulated histamine release from basophils and IL-8 secretion from eosinophils in vitro. Whereas malarial TCTP was less active than HRF, the concentrations that were effective in vitro could be achievable in vivo. These data suggest that malarial TCTP, present in human plasma during a malarial illness, may affect host immune responses in vivo.

Efficacy of rectal artesunate compared with parenteral quinine in initial treatment of moderately severe malaria in African children and adults: a randomised study

BACKGROUND Many patients with malaria of increasing severity cannot take medicines orally, and delay in injectable treatment can be fatal. We aimed to assess the reliability of absorption, antimalarial efficacy, and tolerability of a single rectal dose of artesunate in the initial management of moderately severe falciparum malaria. METHODS 109 children and 35 adults were randomly assigned to rectal artesunate (single dose of about 10 mg/kg) or parenteral quinine treatment (10 mg/kg at 0, 4, and 12 h). The primary endpoint was the proportion of patients with peripheral asexual parasitaemia of less than 60% of that at baseline after 12 h. Secondary endpoints were clinical response and concentrations of drug in plasma. Analysis was by intention-to-treat. FINDINGS All artesunate-treated patients had pharmacodynamic or pharmacokinetic evidence of adequate drug absorption. 80 (92%) of 87 artesunate-treated children had a 12 h parasite density lower than 60% of baseline, compared with three of 22 (14%) receiving quinine (relative risk 0.09 [95% CI 0.04-0.19]; p<0.0001). In adults, parasitaemia at 12 h was lower than 60% of baseline in 26 (96%) of 27 receiving artesunate, compared with three (38%) of eight receiving quinine (relative risk 0.06 [0.01-0.44]; p=0.0009). These differences were greater at 24 h. Clinical response was equivalent with rectal artesunate and parenteral quinine. INTERPRETATION A single rectal dose of artesunate is associated with rapid reduction in parasite density in adults and children with moderately severe malaria, within the initial 24 h of treatment. This option is useful for initiation of treatment in patients unable to take oral medication, particularly where parenteral treatment is unavailable.

The effect of HIV infection on paediatric bacterial meningitis in Blantyre, Malawi

Aim: To compare presentation, progress, and outcome of acute bacterial meningitis in HIV seropositive and seronegative children. Methods: A double blind randomised placebo controlled study of the use of dexamethasone as adjuvant therapy in acute bacterial meningitis, in children aged 2 months to 13 years, was carried out from July 1997 to March 2001. A total of 598 children were enrolled, of whom 459 were tested for HIV serostatus. Results: Of the 459 children, 34% were HIV seropositive. Their presentation was similar to HIV seronegative children but more were shocked on arrival at hospital (33/157 v 12/302), and more had a focus of infection (85/157 v 57/302). HIV positive children had a higher incidence of Streptococcus pneumoniae infections (52% v 32%). Sixty four cases relapsed; 67% were in HIV positive patients. The mortality in HIV positive children was 65% compared with 36% in HIV negative children. The number of survivors in each group was similar. Hearing loss was more common in HIV negative than HIV positive children (66.3% v 47.2%). Steroid therapy had no influence on meningitis in HIV positive children, but the mortality in HIV negative children was 61% in children given steroids, and 39% in those who did not receive steroids. Conclusion: HIV seropositive children who develop bacterial meningitis have a high mortality and are prone to recurrent disease. There is an urgent need to prevent both primary and recurrent infections.

Population pharmacokinetics of artesunate and dihydroartemisinin following intra-rectal dosing of artesunate in malaria patients

Background Intra-rectal artesunate has been developed as a potentially life-saving treatment of severe malaria in rural village settings where administration of parenteral antimalarial drugs is not possible. We studied the population pharmacokinetics of intra-rectal artesunate and the relationship with parasitological responses in patients with moderately severe falciparum malaria. Methods and Findings Adults and children in Africa and Southeast Asia with moderately severe malaria were recruited in two Phase II studies (12 adults from Southeast Asia and 11 children from Africa) with intensive sampling protocols, and three Phase III studies (44 children from Southeast Asia, and 86 children and 26 adults from Africa) with sparse sampling. All patients received 10 mg/kg artesunate as a single intra-rectal dose of suppositories. Venous blood samples were taken during a period of 24 h following dosing. Plasma artesunate and dihydroartemisinin (DHA, the main biologically active metabolite) concentrations were measured by high-performance liquid chromatography with electrochemical detection. The pharmacokinetic properties of DHA were determined using nonlinear mixed-effects modelling. Artesunate is rapidly hydrolysed in vivo to DHA, and this contributes the majority of antimalarial activity. For DHA, a one-compartment model assuming complete conversion from artesunate and first-order appearance and elimination kinetics gave the best fit to the data. The mean population estimate of apparent clearance (CL/F) was 2.64 (l/kg/h) with 66% inter-individual variability. The apparent volume of distribution (V/F) was 2.75 (l/kg) with 96% inter-individual variability. The estimated DHA population mean elimination half-life was 43 min. Gender was associated with increased mean CL/F by 1.14 (95% CI: 0.36–1.92) (l/kg/h) for a male compared with a female, and weight was positively associated with V/F. Larger V/Fs were observed for the patients requiring early rescue treatment compared with the remainder, independent of any confounders. No associations between the parasitological responses and the posterior individual estimates of V/F, CL/F, and AUC0–6h were observed. Conclusions The pharmacokinetic properties of DHA were affected only by gender and body weight. Patients with the lowest area under the DHA concentration curve did not have slower parasite clearance, suggesting that rectal artesunate is well absorbed in most patients with moderately severe malaria. However, a number of modelling assumptions were required due to the large intra- and inter-individual variability of the DHA concentrations.

Hearing loss in Malawian children after bacterial meningitis: incidence and risk factors

We had an objective to describe the incidence and risk factors for hearing loss following acute bacterial meningitis in children admitted to the Queen Elizabeth Central Hospital (QECH), Blantyre, Malawi. A double‐blind placebo‐controlled trial was designed from July 1997–March 2001 to determine whether early steroid therapy would reduce overall mortality and morbidity in childhood bacterial meningitis. The QECH, Blantyre, Malawi is a teaching and referral public hospital that serves the Blantyre area and receives referrals from throughout southern Malawi. Participants were children aged 2 months to 13 years, admitted with a diagnosis of bacterial meningitis, and the main outcome measures were mortality and morbidity following bacterial meningitis. Three hundred and ninety‐nine of 598 (66.7%) children survived; 33.6% were due to S. pneumoniae, 30% to Haemophilus influenzae type b, 15% to Neisseria meningitides, and 16% had no growth on CSF culture. Two hundred and sixty‐eight (67%) survivors had reliable hearing tests of whom 38% had impaired hearing, 77% of which was bilateral. Independent risk factors for hearing loss were the causative agent, presentation with a low coma score (52% vs. 34%, p = 0.006), a first CSF sample with a positive Gram stain for bacteria (65% vs. 44.3%, p = 0.003), a WBC < 100/cmm (p = 0.01), or a high protein level (50% if > 2000 mg/dl vs. 11% if <100 mg/dl). Associated neurological sequelae were highly associated with hearing impairment (p = 0.000012). We conclude that bacterial meningitis is the cause of many childrens hearing impairment. Immunization against S. pneumoniae and H. influenzae would prevent many cases. Better first line antibiotics may reduce audiological damage. Deaf children in poorer parts of the world need more and vocal advocacy.