Imported falciparum malaria among adults requiring intensive care: analysis of the literature

How to manage adult patients with malaria in the non-endemic setting

BACKGROUND

The diagnosis and management of malaria in non-endemic countries presents a continuing challenge. Plasmodium falciparum, which is capable to rapidly induce severe and life-threatening multiorgan disease, is the species most frequently diagnosed in Europe and North America.

OBJECTIVES

To summarise the more relevant diagnostic findings and clinical features of malaria observed in non-endemic settings and to provide an up-date of the key management decision points using three illustrative clinical scenarios of uncomplicated and severe malaria.

SOURCES

The discussion is based on relevant literature search spanning the last twenty years. Recommendations are based on available clinical guidelines including those of the World Health Organization (WHO), on observational studies conducted in non-endemic settings and, when available, with extrapolation from randomised studies from malaria endemic settings.

CONTENT

The following topics are covered: diagnosis, including the use of molecular biology; clinical characteristics; management with specific focus on complicated (severe) and uncomplicated malaria and on areas of resistance to available antimalarial drugs.

IMPLICATIONS

Malaria imported to non-endemic settings, especially Plasmodium falciparum malaria, is sometimes initially overlooked and the delayed diagnosis is responsible every year of preventable deaths. This review aims to raise awareness of malaria outside endemic countries and to provide clinicians with a practical guide for efficient diagnosis and targeted therapy to the different species involved.

Assessing viral metagenomics for the diagnosis of acute undifferentiated fever in returned travellers: a multicenter cohort study

BACKGROUND

Up to 45% of febrile returning travellers remain undiagnosed after a thorough diagnostic work-up, even at referral centres. Although metagenomic next-generation sequencing (mNGS) has emerged as a promising tool, evidence of its usefulness in imported fever is very limited.

METHODS

Travellers returning with fever were prospectively recruited in three referral clinics from November 2017 to November 2019. Unbiased mNGS optimised for virus detection was performed on serum samples of participants with acute undifferentiated febrile illness (AUFI), and results were compared to those obtained by reference diagnostic methods (RDM).

RESULTS

Among 507 returned febrile travellers, 433(85.4%) presented with AUFI. Dengue virus (n = 86) and Plasmodium spp. (n = 83) were the most common causes of fever. 103/433(23.8%) AUFI remained undiagnosed at the end of the follow-up.Metagenomic next-generation sequencing unveiled potentially pathogenic microorganisms in 196/433(38.7%) AUFI. mNGS identifications were more common in patients with a shorter duration of fever (42.3% in ≤5 days vs 28.7% in >5 days, P = 0.005). Potential causes of fever were revealed in 25/103(24.2%) undiagnosed AUFI and 5/23(21.7%) travellers with severe undiagnosed AUFI. Missed severe aetiologies included eight bacterial identifications and one co-infection of B19 parvovirus and Aspergillus spp.Additional identifications indicating possible co-infections occurred in 29/316(9.2%) travellers with AUFI, and in 11/128(8.6%) travellers with severe AUFI, who had received a diagnosis through RDM. The most common co-infections detected in severe AUFI were caused by Gram-negative bacteria. Serum mNGS was unable to detect >50% of infectious diagnoses achieved by RDM and also yielded 607 non-pathogenic identifications.

DISCUSSION

mNGS of serum can be a valuable diagnostic tool for selected travellers with undiagnosed AUFI or severe disease in addition to reference diagnostic techniques, especially during the first days of symptoms. Nevertheless, mNGS results interpretation presents a great challenge. Further studies evaluating the performance of mNGS using different sample types and protocols tailored to non-viral agents are needed.

The Emergence of Travel-related Infections in Critical Care Units

Several tropical or geographically confined infectious diseases may lead to organ failure requiring management in an intensive care unit (ICU), both in endemic low- and middle-income countries where ICU facilities are increasingly being developed and in (nonendemic) high-income countries through an increase in international travel and migration. The ICU physician must know which of these diseases may be encountered and how to recognize, differentiate, and treat them. The four historically most prevalent "tropical" diseases (malaria, enteric fever, dengue, and rickettsiosis) can present with single or multiple organ failure in a very similar manner, which makes differentiation based solely on clinical signs very difficult. Specific but frequently subtle symptoms should be considered and related to the travel history of the patient, the geographic distribution of these diseases, and the incubation period. In the future, ICU physicians may also be more frequently confronted with rare but frequently lethal diseases, such as Ebola and other viral hemorrhagic fevers, leptospirosis, and yellow fever. No one could have foreseen the worldwide 2019-up to now coronavirus disease 2019 (COVID-19) crisis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was initially spread by travel too. In addition, the actual pandemic due to SARS-CoV-2 reminds us of the actual and potential threat of (re)-emerging pathogens. If left untreated or when treated with a delay, many travel-related diseases remain an important cause of morbidity and even mortality, even when high-quality critical care is provided. Awareness and a high index of suspicion of these diseases is a key skill for the ICU physicians of today and tomorrow to develop.

Fluid therapy for severe malaria

Fluid therapy is an important supportive measure for patients with severe malaria. Patients with severe malaria usually have normal cardiac index, vascular resistance, and blood pressure and a small degree of hypovolaemia due to dehydration. Cell hypoxia, reduced kidney function, and acidosis result from microcirculatory compromise and malarial anaemia, which reduce tissue oxygenation, not hypovolaemia. Hence, aggressive fluid loading does not correct acid-base status, enhance kidney function, or improve patient outcomes, and it risks complications such as pulmonary oedema. Individualised conservative fluid management is recommended in patients with severe malaria. Physical examination and physiological indices have limited reliability in guiding fluid therapy. Invasive measures can be more accurate than physical examination and physiological indices but are often unavailable in endemic areas, and non-invasive measures, such as ultrasound, are mostly unexplored. Research into reliable methods applicable in low-resource settings to measure fluid status and response is a priority. In this Review, we outline the current knowledge on fluid management in severe malaria and highlight research needed to optimise fluid therapy and improve survival in severe malaria.

Time for pragmatic, prospective clinical trials to determine the role of empirical antibacterial therapy in critically ill adults hospitalized with malaria

BACKGROUND

Children with severe falciparum malaria in malaria-endemic regions are predisposed to developing life-threatening bacterial co-infection. International guidelines therefore recommend empirical broad-spectrum antibacterial therapy in these children. Few studies have examined co-infection in adults, although it has been believed to be relatively rare; antibacterial therapy is therefore not routinely recommended in adults with falciparum malaria.

DISCUSSION

However, the fundamental pathophysiology of falciparum malaria in adults and children is the same; it is therefore unclear why adults would not also be predisposed to bacterial infection. Indeed, recent studies have identified bacteraemia in >10% of adults hospitalized with malaria. Some have suggested that these adults probably had bacterial sepsis, with the parasitaemia an incidental finding. However, it is usually impossible in resource-limited settings to determine-at presentation-whether critically ill, parasitaemic adults have severe malaria, bacterial sepsis, or both. Given the significant case-fatality rates of severe malaria and bacterial sepsis, the pragmatic initial approach would be to cover both possibilities.

CONCLUSIONS

Life-threatening bacterial co-infection may be more common in critically ill adults with malaria than previously believed. While further prospective data are awaited to confirm these findings, it might be more appropriate to provide empirical aantibacterial cover in these patients than current guidelines suggest.

Effect of Impregnated Mosquito Bed Nets on the Prevalence of Malaria among Pregnant Women in Foumban Subdivision, West Region of Cameroon

Background

Malaria is one of the major public health problems in many tropical developing countries including Cameroon. Impregnated mosquito bed nets are one of the control measures put in place by the WHO and adopted by the Cameroon's Ministry of Public Health to fight against malaria in pregnancy. This study was a population-based cross-sectional study that investigated the level of adherence, respondent's knowledge, altitude, and practices toward malaria prevention and control.

Methods

To investigate this, a sample size of 410 pregnant women who were inhabitants of Foumban Subdivision was examined. Data on net ownership versus usage, pregnancy status, and socioeconomic background were collected using a questionnaire. Parasitological tests for malaria parasites were carried out using peripheral blood samples obtained from finger pricks of the pregnant women for the preparation of thick blood smear and RDTs.

Results

Two hundred and eighteen tested positive (53.4%) with the highest prevalence occurring during the first trimester (79.6%) and in primigravidae (68.8%). Participants believed that mosquito bed nets can protect them against malaria infection. The highest number (81.0%) of the women who had mosquito nets acquired them during antenatal visits. Among those who possessed nets, 42.7% adhered to sleeping under them and few (50%) experienced problems of sweating, discomfort, and heat. Also, the study revealed a high prevalence rate of 63.8% for those who did not use nets during pregnancy as compared to those who owned and used them.

Conclusion

The findings indicated that increased access to impregnated mosquito bed nets is required to lower the risk of malaria infection amongst pregnant women. The Cameroon government should improve health education to families within the locality and pursue an integrated approach to fight against mosquitoes during the rainy season.

Descriptive Acute Respiratory Distress Syndrome (ARDS) in adults with imported severe Plasmodium falciparum malaria: A 10 year-study in a Portuguese tertiary care hospital

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe complication of malaria that remains largely unstudied. We aim to describe the development of ARDS associated with severe P. falciparum malaria, its management and impact on clinical outcome.

METHODS

Retrospective observational study of adult patients admitted with severe P. falciparum malaria in an Intensive Care Unit (ICU) of a tertiary care hospital from Portugal from 2008 to 2018. A multivariate logistic regression analysis was used to identify factors associated with the development of ARDS, defined according to Berlin Criteria. Prognosis was assessed by case-fatality ratio, nosocomial infection and length of stay.

RESULTS

98 patients were enrolled, of which 32 (33%) developed ARDS, a median of 2 days after starting antimalarial medication (IQR 0-4, range 0-6). Length of stay in ICU and in hospital were significantly longer in patients who developed ARDS: 13 days (IQR 10-18) vs 3 days (IQR 2-5) and 21 days (IQR 15-30.5) vs 7 days (IQR 6-10), respectively. Overall case-fatality ratio in ICU was 4.1% and did not differ between groups. The risk of ARDS development is difficult to establish.

CONCLUSION

ARDS is a hard to predict late complication of severe malaria. A low threshold for ICU admission and monitoring should be used. Ideally patients should be managed in a centre with experience and access to advanced techniques.

Management of severe imported malaria in adults

Severe malaria accounts for approximately 10% of all cases of imported malaria in France; cases are mainly due to Plasmodium falciparum, while other Plasmodium species are possible but uncommon (P. vivax, P. knowlesi, P. malariae, and P. ovale). On the basis of WHO criteria for endemic areas, the French criteria defining severe imported malaria in adults have been progressively adapted to the European healthcare level. Management of severe imported malaria is a diagnostic and treatment emergency and must be initially conducted in the intensive care unit. Anti-infective treatment is now based on intravenous artesunate, which must be available in every hospital of the country likely to receive severe imported malaria patients. Intravenous quinine is thus used as a second-line treatment and is restricted to limited indications. Critical care management of organ failure is essential, particularly in patients presenting with very severe malaria. To date, no adjunctive therapy (including exchange transfusion) has demonstrated clear beneficial effects.

Prise en charge du paludisme grave d’importation de l’adulte

En France, le paludisme grave d’importation concerne environ 12 à 14 % des accès palustres et implique très majoritairement Plasmodium falciparum. À partir de la définition du paludisme grave de l’Organisation mondiale de la santé utilisée en zone d’endémie palustre, la définition française du paludisme grave d’importation de l’adulte a été adaptée aux données et au contexte européens. La prise en charge du paludisme grave est une urgence diagnostique et thérapeutique qui doit être réalisée initialement en réanimation. Le traitement curatif du paludisme grave d’importation repose maintenant sur l’artésunate intraveineux (IV) qui doit être disponible dans chaque hôpital susceptible de recevoir ces patients. Dès lors, la quinine IV devient un traitement de seconde ligne réservé à quelques circonstances. La prise en charge symptomatique des défaillances d’organes est primordiale, notamment au cours des formes les plus sévères. Enfin, aucun traitement adjuvant n’a prouvé, à ce jour, son efficacité en pratique clinique.

Circulating microRNAs in malaria infection: bench to bedside

Severe malaria has a poor prognosis with a morbidity rate of 80% in tropical areas. The early parasite detection is one of the effective means to prevent severe malaria of which specific treatment strategies are limited. Many clinical characteristics and laboratory testings have been used for the early diagnosis and prediction of severe disease. However, a few of these factors could be applied to clinical practice. MicroRNAs (miRNAs) were demonstrated as useful biomarkers in many diseases such as malignant diseases and cardiovascular diseases. Recently it was found that plasma miR-451 and miR-16 were downregulated in malaria infection at parasitic stages or with multi-organ failure involvement. MiR-125b, -27a, -23a, -150, 17-92 and -24 are deregulated in malaria patients with multiple organ failures. Here, the current findings of miRNAs were reviewed in relation to clinical severity of malaria infection and emphasized that miRNAs are potential biomarkers for severe malaria infection.

Severe Plasmodium falciparum malaria in the intensive care unit: A 6-year experience in Milano, Italy

BACKGROUND

Severe imported Plasmodium falciparum malaria is a potentially life-threatening disease with a reported mortality rate of 5-10% when patients are admitted to the Intensive Care Unit.

METHODS

To retrospectively review the clinical aspects, the value of severity predictive scores and the management of patients with severe P. falciparum malaria admitted to an ICU in Milano, Italy between January 2010 and December 2015.

RESULTS

Twelve patients were included: seven were male and five female with a median age of 43 years. All were initially treated with intravenous quinine. Median parasitaemia upon admission was 14,5% (range 1-20%). At the time of ICU admission, 3 patients (25%) had 5 or more World Health Organization criteria for severe malaria while another 6 of them developed one or more of the latter during their stay in ICU. Five required mechanical ventilation because of respiratory failure due to ARDS. Four patients required renal replacement therapy. Three patients underwent blood exchange transfusion. All patients survived.

CONCLUSIONS

Our retrospective evaluation of adults patients admitted to the ICU with severe imported P. falciparum malaria demonstrated a favourable outcome. Severity predictive scores currently in use probably overestimate the risk of malaria mortality in patients treated in health care systems of high income countries.

Urinalysis and Clinical Correlations in Patients with P. vivax or P. falciparum Malaria from Colombia

BACKGROUND

Urinalysis is a poorly reviewed diagnostic tool in malaria patients; its application can show the presence of severe malaria.

METHODS

Urinalysis was performed in a total of 620 patients diagnosed with malaria by thick blood smear; complications were classified according to WHO major criteria for severity and minor criteria according to the Colombian malaria guideline.

RESULTS

Severe or moderate clinical complications were diagnosed in 31.1% of patients, hepatic dysfunctions were diagnosed in 25.8%, anemia was diagnosed in 9.8%, thrombocytopenia was diagnosed in 7.7%, renal dysfunction was diagnosed in 4.8%, neurological and pulmonary complications were diagnosed in 2.1% and 2.4%, hypoglycemia was diagnosed in 1.1% of patients with blood glucose analysis, and acidosis was diagnosed in 10 of 25. Bilirubinuria was found in 24.3%, associated with urobilinuria, proteinuria, and increased specific gravity; urobilinuria was found in 30.6% associated with elevated serum bilirubin and alanine aminotransferase; 39.2% had proteinuria, associated with higher blood urea nitrogen, serum bilirubin, aspartate, alanine-transaminase, hematuria, and increased specific gravity. Severe or moderate liver and renal complications were associated with proteinuria and bilirubinuria. Urobilinuria was associated with thrombocytopenia and neurological and hepatic dysfunction. Ketonuria was associated with neurological dysfunctions.

CONCLUSIONS

The most frequent alterations in the urinalysis were bilirubinuria, proteinuria, urobilinuria, and increased specific gravity, related to thrombocytopenia and liver, kidney, and neurological alterations.

Severe vivax malaria: a prospective exploration at a tertiary healthcare centre in Southwestern India

Plasmodium vivax is recognized to cause severe malaria and mortality. We aimed to determine the proportion of disease severity, the spectrum of complications, underlying non-infectious comorbidities and predictors of severity in monoinfection P. vivax malaria among adults at a tertiary healthcare centre in Southwestern India. A prospective cohort study was conducted among microscopically confirmed monoinfection P. vivax acute malaria patients aged, ≥18 years. Cases with pregnancy and concomitant febrile illnesses including mixed malaria were excluded. Cases were distinguished as either 'severe' or 'non-severe' P. vivax malaria as per the definitions laid by the World Health Organization. Of total 511 acute P. vivax cases studied, 23.9% (122/511) had severe malaria. The proportion of severity did not vary between microscopy alone and additional nPCR proved monoinfection P. vivax subgroups. There was no significant difference (p = 0.296) in the occurrence of non-infectious comorbidities among non-severe (9.0%, 35/389) and severe (12.3%, 15/122) vivax groups. Multiple complications despite early parasite clearance resulted in delayed casualty in two cases, indicating overall case fatality rate of 3/1000 cases. Age >40 years, rising respiratory rate, total bilirubin, serum creatinine and falling hemoglobin were the independent predictors of disease severity in this vivax malaria cohort. Total and direct bilirubin and serum urea had good discriminatory performance for severe vivax malaria. Total bilirubin should be considered as an important prognostic marker while managing P. vivax malaria. Patients with multiple complications must be treated cautiously as there may be delayed deterioration leading to mortality despite parasite clearance.

Surveillance and response strategy in the malaria post-elimination stage: case study of Fujian province

Malaria used to be a serious health problem in Fujian province in the past, but no local malaria transmission has been found since 2000. In order to eliminate the potential residual cases and prevent re-introduction of malaria so as to achieve the final goal of malaria elimination in Fujian province, various strategy and intervention approaches were tailored to the local settings. For instance, the monitoring of febrile patients by blood smear examinations and vector surveillance and control were strengthened in addition to the routine intervention in the mountainous area of Fujian province, where malaria was highly endemic and the mosquito Anopheles anthropophagus distributed with a high vectorial capacity. There were two local cases who got infected due to imported cases found in the building site of an expressway in 2004 and 2005, respective. All other imported malaria cases were detected during post-elimination stage through surveillance system. Based on results from post-transmission surveillance, malaria transmission has been interrupted in Fujian province for 13 years. Therefore, post-transmission surveillance and response is an important intervention to maintain the malaria elimination achievements in Fujian province.

Severity in Plasmodium vivax malaria claiming global vigilance and exploration--a tertiary care centre-based cohort study

BACKGROUND

Mounting reports on severe Plasmodium vivax malaria from across the globe have raised concerns among the scientific community. However, the risk of P. vivax resulting in complicated malaria and mortality is not as firmly established as it is with Plasmodium falciparum. This study was conducted to determine the severity proportion and factors associated with severity in cases of vivax and falciparum malaria.

METHODS

Adult patients microscopically diagnosed to have P. vivax/P. falciparum infections from the year 2007-2011 were evaluated based on their hospital records. Severe malaria was defined as per the World Health Organization's guidelines. Comparison was made across species and binary logistic regression was used to determine risk factors of severity.

RESULTS

Of 922 malaria cases included in the study, P. vivax was the largest (63.4%, 95% confidence interval (CI) 60.3-66.5%) infecting species, followed by P. falciparum (34.4%, 95% CI 31.3-37.5%) and their mixed infection (2.2%, 95% CI 1.3-3.2%). Severity in P. vivax and P. falciparum was noted to be 16.9% (95% CI 13.9-19.9%) and 36.3% (95% CI 31.0-41.6%) respectively. Plasmodium falciparum had significantly higher odds [adjusted odds ratio (95% CI), 2.80 (2.04-3.83)] of severe malaria than P. vivax. Rising respiratory rate [1.29 (1.15-1.46)], falling systolic blood pressure [0.96 (0.93-0.99)], leucocytosis [12.87 (1.43-115.93)] and haematuria [59.36 (13.51-260.81)] were the independent predictors of severity in P. vivax. Increasing parasite index [2.97 (1.11-7.98)] alone was the independent predictor of severity in P. falciparum. Mortality in vivax and falciparum malaria was 0.34% (95% CI -0.13-0.81%) and 2.21% (95% CI 0.59-3.83%), respectively. Except hyperparasitaemia and shock, other complications were associated (P < 0.05) with mortality in falciparum malaria. Pulmonary oedema/acute respiratory distress syndrome was associated (P = 0.003) with mortality in vivax malaria. Retrospective design of this study possesses inherent limitations.

CONCLUSIONS

Plasmodium vivax does cause severe malaria and mortality in substantial proportion but results in much lesser amalgamations of multi-organ involvements than P. falciparum. Pulmonary oedema/acute respiratory distress syndrome in P. vivax infection could lead to mortality and therefore should be diagnosed and treated promptly. Mounting complications and its broadening spectrum in 'not so benign' P. vivax warrants global vigilance for any probable impositions.