N-acetylcysteine in severe falciparum malaria in Thailand

One hundred and eight patients with severe falciparum malaria underwent a placebo controlled trial with the antioxidant, N-acetylcysteine (NAC), as an adjunctive therapy along with standard intravenous artesunate therapy. Three NAC dosage regimens were used: an intravenous loading dose of 140 mg/kg followed by 70 mg/kg every four hours intravenously for up to 18 doses (Group 1); a single intravenous loading dose followed by oral NAC in the same amount as for Group 1 (Group 2); a regimen identical to Group 1 except that oral NAC was administered after the first 24 hours (Group 3). Fifty-four patients received placebo plus artesunate. Two critically ill patients died in Group 1. No patient sustained an adverse reaction to the NAC other than vomiting, and the deaths were attributed to severe disease with multiple organ involvement. The excellent results with NAC, the lack of adverse effects, and the rationale for NAC benefit supports the need for a large, double blind trial of NAC as an adjunctive therapy for severe malaria.     

Erythrocyte survival in severe falciparum malaria.

Erythrocyte survival was studied in 17 Thai patients (10 males, 7 females; aged 13-57 years) with severe falciparum malaria. To ensure radioisotopic labelling of cells before bone marrow recovery and survival analysis under near-steady state conditions, 51Cr labelling of autologous erythrocytes was performed at the time of admission (0 h) and calculation of mean cell lifespan (MCL) was based on semilogarithmic plots of corrected counts from 60 h onwards. Five patients received blood transfusions, all within 48 h of admission. The overall mean (+/- S.D.) MCL was short (44.1 +/- 21.7 days). Nontransfused patients had similar MCL values (43.6 +/- 20.4) to those of transfused patients (45.5 +/- 27.3 days, p greater than 0.8). Patients with and without palpable splenomegaly had MCL values which were not significantly different (54.1 +/- 28.8 vs. 37.2 +/- 12.3 days respectively, p greater than 0.1). There was no association between admission haematocrit or peripheral parasitaemia and MCL (p greater than 0.2 in each case), but there was an inverse correlation between total serum bilirubin and MCL (r = -0.49, p less than 0.025). There is accelerated destruction of non-parasitised erythrocytes in severe malaria resulting in a mean MCL that is half that found previously in healthy Thai volunteers (89.6 +/- 13.1 days, p less than 0.001) and significantly shorter than that reported previously in Thai patients with uncomplicated P. falciparum infections studied after parasite clearance (56.8 +/- 10.2 days, p less than 0.05).     

重症恶性脑型疟疾的细胞粘附机制

疟疾约占世界感染性疾病的 2 .3% ,仅次于急性肺炎球菌呼吸道感染 (3.5 % )和结核病 (2 .8% ) ,是世界上第 3位重要的感染性疾病。每年约有 15 0～ 2 70万患者死于疟疾 ,主要在非洲 ,其中大多是婴儿和 5岁以下儿童。在感染人的 4种疟原虫中 ,恶性疟原虫(Plasmodium falciparum,P.f)危害最严重 ,可引起多个重要脏器功能障碍 ,发生重症疟疾 ,病死率高达15 %～ 30 %。其中重症脑型疟疾死亡率最高 ,其病理基础是感染疟原虫的红细胞 (IRBC)在脑深部血管床内滞留 (sequestration) ,造成代谢、机能紊乱而出现多种临床表现。其病理机制有“沉积 (…     

Clearance kinetics of parasites and pigment-containing leukocytes in severe malaria

In tropical areas, where unsupervised use of antimalarial drugs is common, patients with an illness consistent clinically with severe malaria but with negative blood smears pose a management dilemma. Malaria pigment is evident in peripheral blood leukocytes in greater than 90% of patients with severe malaria. To characterize the clearance kinetics of parasitized erythrocytes and malaria pigment-containing leukocytes, sequential peripheral blood and intradermal smears were assessed in 27 adult Vietnamese patients with severe falciparum malaria. The clearance of parasitized erythrocytes and pigment- containing monocytes (PCMs) followed first order kinetics. The elimination of pigment-containing neutrophils (PCNs) was first order initially, but deviated from this when counts were low. Clearance of peripheral blood PCMs (median clearance time, 216 hours; range, 84 to 492 hours) was significantly slower than that of parasitized erythrocytes (median, 96 hours; range, 36 to 168 hours) or PCNs (median, 72 hours; range, 0 to 168 hours; P < .0001). Intradermal PCM clearance times were the longest of all (median, 12 days; range, 6 to 23 days; significantly longer than peripheral blood PCM clearance, P < .001). Twenty-one (88%) patients still had signs, symptoms, or laboratory features of severe malaria after parasite clearance but before phagocyte pigment clearance. Sixteen of the 23 surviving patients (70%; 95% confidence interval, 50% to 87%) still had intraleukocytic malaria pigment on peripheral blood films 72 hours after parasite clearance. Thus, by determining the distribution of malaria pigment in peripheral blood and intradermal phagocytes, the time since effective antimalarial treatment started can be estimated. Microscopy for intraleukocytic pigment is valuable in the differential diagnosis of severe febrile illnesses in malarious areas where uncontrolled use of antimalarial drugs is widespread.     

Developmental impairments following severe falciparum malaria in children

OBJECTIVE: Neurological deficits are reported in children after cerebral malaria (CM) but little is known about the prevalence and characteristics of persisting neurocognitive consequences. The prevalence of developmental impairments following other complications of falciparum malaria, such as multiple, prolonged or focal seizures, is not known. Thus, our objective was to investigate the long-term developmental outcome of CM and malaria with complicated seizures (M/S). METHODS: We followed up a cohort of children previously exposed to CM or M/S and children unexposed to either condition. All children between 6 and 9 years of age, exposed to CM, and an equal number of children exposed to M/S were identified from databases of hospital admissions from 1991 to 1998. The unexposed group was randomly selected from a census database. The children's performance was measured using assessments of cognition, motor, speech and language, hearing and vision. A parental questionnaire was used to identify children with epilepsy. RESULTS: CM group scores were significantly lower than unexposed group scores on the assessments of higher level language (adjusted mean difference -1.63, 95% CI: -2.99 to -0.27), vocabulary (-0.02, 95% CI: -0.04 to -0.01), pragmatics (OR 2.81, 95% CI: 1.04-7.6) and non-verbal functioning (-0.33, 95% CI: -0.61 to -0.06). The areas of significantly reduced functioning for the M/S group were concentrated on phonology (OR 2.74, 95% CI: 1.26-5.95), pragmatics (OR 3.23, 95% CI: 1.2-8.71) and behaviour (OR 1.8, 95% CI: 1.0-3.23). The performance of the active epilepsy group was significantly poorer than that of the group without epilepsy on the tests of comprehension, syntax, pragmatics, word finding, memory, attention, behaviour and motor skills. CONCLUSIONS: CM and M/S are associated with developmental impairments. If these impairments persist, this may have implications for least 250,000 children in Sub-Saharan Africa each year. Active epilepsy significantly increases the risk of cognitive and behavioural problems in children with a history of severe malaria.     

Prognostic value of thrombocytopenia in African children with falciparum malaria

Thrombocytopenia is a common finding in malaria, but its prognostic value has not been addressed in children. The relationship between thrombocytopenia (platelet count < 100,000/mm3 on admission) and severity and outcome was investigated prospectively in children hospitalized with falciparum malaria in Dakar, Senegal, an area that is hypoendemic for malaria. Of 288 falciparum cases, 215 matched the 2000 World Health Organization definition of severe malaria. Median platelet counts were lower (98,000/mm3 versus 139,000/mm3; P < 0.02) among severe cases than in mild cases, and in children who died than among those who recovered (68,500/mm3 versus 109,000/mm3; P < 0.002). In severe cases, children presenting with a platelet count < 100,000/mm3 were more likely to die (odds ratio [OR] = 6.31, 95% confidence interval [CI] = 2.0-26.0). Moreover, multivariate analysis identified thrombocytopenia as an independent predictor of death (OR = 13.3, 95% CI = 3.2-55.1). Our data show an association between thrombocytopenia and either severity or prognosis in childhood falciparum malaria.     

Changes in platelet count in uncomplicated and severe falciparum malaria

This study investigated alterations in platelet counts pre- and post-treatment with artemisinin derivatives in uncomplicated and severe falciparum malaria. Serial platelet counts were taken over 4 weeks for 110 uncomplicated and 110 severe falciparum malaria patients admitted to the Hospital for Tropical Diseases during 2005-2008. On admission, prior to treatment, thrombocytopenia was found in 73.6% of uncomplicated falciparum malaria patients and 90.9% of severe falciparum malaria cases. Platelet levels significantly lower in severe malaria cases. Although initial platelet counts were lower than normal in both study groups, they slowly increased significantly over time, and approached normal levels by several weeks post-treatment. No bleeding was evident during treatment, and none of the patients required a platelet transfusion. Platelet transfusions are not required for malaria patients with thrombocytopenia who have no bleeding.     

Automated erythrocytapheresis in the treatment of severe falciparum malaria

Removal of parasitized erythrocytes is generally considered to be of value as adjunctive therapy in severe falciparum malaria with high parasitaemia. This is commonly achieved by exchange transfusion. We describe three cases of severe falciparum malaria treated by automated erythrocytapheresis (red cell exchange) in addition to quinine and conventional supportive therapy. Erythrocytapheresis consists of removal of the red-cell fraction by apheresis. Plasma, leukocyte and platelet fractions are returned to the patient. In all cases, dramatic reduction in parasitaemia was achieved within 2 h with subsequent complete clinical recovery. Erythrocytapheresis has significant advantages over exchange transfusion in terms of speed, efficiency, haemodynamic stability and retention of plasma components such as clotting factors and may thus represent an improvement in adjunctive therapy for severe malaria.     

输入性重症脑型恶性疟1例报告

患者，男性，34岁，农民，汉源县三郊乡永河村人，因寒战、发热7d。昏迷12h于2006年5月5日入院。7d前患者无明显诱因下出现寒战、发热（39．5℃）（为不规则发热，4～5h后热退，无出汗）伴头昏、呕吐、乏力、腹胀、纳差，在当地诊所治疗无好转，12h前出现昏迷，四肢强直，口吐泡沫，送入本院。     

Fluid management of severe falciparum malaria in African children

Most African children with severe malaria who die do so on the day of admission as a result of the complications of falciparum malaria. We highlight the value of a rapid structured triage assessment to look for emergency signs that will prioritize initial management and implementation of basic life support. This can be delivered with few resources and by non-specialist medical personnel. Reduction in case fatality can only come through the wider appreciation of the need for and application of supportive therapies to treat the life-threatening complications. Hypovolaemia has emerged as a common feature of children presenting with severe malaria complicated by acidosis. Early recognition and prompt treatment may lead to improvements in outcome. We discuss the new evidence supporting the role of hypovolaemia in severe malaria and potential treatment options whilst awaiting the results of clinical trials.     

Cerebral venous and dural sinus thrombosis in severe falciparum malaria

Common causes of coma in falciparum malaria are cerebral malaria, hypoglycaemia and electrolyte disturbances. Focal deficits due to arterial infarcts may sometimes occur in children, but are rare in adults. Three adults with falciparum malaria who had fever, altered consciousness and focal neurological deficits (one of whom also had seizures) are being reported here. CT scan of the brain revealed haemorrhagic infarction of the cerebral cortex and subcortical white matter with surrounding oedema suggestive of venous infarction in all three patients. The diagnosis of cerebral venous thrombosis was missed in the first patient, and was detected only at autopsy. In the next two patients, superior sagittal sinus thrombosis was confirmed angiographically. Only one patient survived; the other two died of increased intracranial pressure. Two of the three patients also had Plasmodium vivax co-infection. A hypercoagulable state resulting from severe malaria may be responsible for this rare and potentially fatal complication. Cerebral malaria may be associated with raised intracranial pressure due to cerebral oedema. Cerebral venous thrombosis may worsen this and adversely affect outcome. This diagnosis should be suspected in patients with severe malaria who develop focal neurological deficits and confirmed by appropriate imaging; judicious use of local thrombolytic therapy may help improve outcome.     

Levamisole inhibits sequestration of infected red blood cells in patients with falciparum malaria

BACKGROUND: Sequestration of infected red blood cells (iRBCs) in the microcirculation is central to the pathophysiology of falciparum malaria. It is caused by cytoadhesion of iRBCs to vascular endothelium, mediated through the binding of Plasmodium falciparum erythrocyte membrane protein-1 to several endothelial receptors. Binding to CD36, the major vascular receptor, is stabilized through dephosphorylation of CD36 by an alkaline phosphatase. This is inhibited by the alkaline phosphatase-inhibitor levamisole, resulting in decreased cytoadhesion. METHODS: Patients with uncomplicated falciparum malaria were randomized to receive either quinine treatment alone or treatment with a single 150-mg dose of levamisole as an adjunct to quinine. Peripheral blood parasitemia and parasite stage distribution were monitored closely over time. RESULTS: Compared with those in control subjects, peripheral blood parasitemias of mature P. falciparum parasites increased during the 24 h after levamisole administration (n=21; P=.006). The sequestration ratio (between observed and expected peripheral blood parasitemia) of early trophozoite and midtrophozoite parasites increased after levamisole treatment, with near complete prevention of early trophozoite sequestration and >65% prevention of midtrophozoite sequestration. CONCLUSION: These findings strongly suggest that levamisole decreases iRBC sequestration in falciparum malaria in vivo and should be considered as a potential adjunctive treatment for severe falciparum malaria. TRIAL REGISTRATION: Current Controlled Trials identifier: 15314870.     

Microvascular sequestration of parasitized erythrocytes in human falciparum malaria: a pathological study

Thirty-nine falciparum malaria autopsy cases from the Hospital for Tropical Diseases, Mahidol University, Bangkok, Thailand were divided into two groups that had had either cerebral malaria (CM) or non-cerebral malaria (NCM). We then studied significant pathological differences between these groups in order to investigate the correlation between parasitized erythrocyte (PRBC) sequestration in small blood vessels in the brain, heart, lungs and small intestines. We found that the percentage of PRBC sequestration in the organs which we studied was higher in the CM patients than in the NCM patients. The difference of PRBC sequestration among the organs of two groups was significant (P less than 0.05). In the CM group, the average percentage of PRBC sequestration in the brain was significantly higher than in the heart, lungs and small intestines (P less than 0.05). No statistically significant difference was found between PRBC sequestration in the brains, hearts, lungs and small intestines in the NCM group (P greater than 0.05). Our study indicates that severity of malaria in the CM patients depends on PRBC sequestration, especially in the brain. A combination of functional disturbances of the other organs, in addition to the cerebral pathology, may augment the severity of the disease.