Cardiac function in Vietnamese patients with different dengue severity grades

Myocarditis manifestations in dengue cases: A systematic review and meta-analysis

BACKGROUND

Dengue fever is a zoonotic viral infection that raises a global alarm in the tropics and subtropics, with the potentially escalating into newer geographical regions. Severe dengue may be associated with fatal complications such as myocarditis. There is a paucity of available data on the prevalence of dengue-associated myocarditis. The objective of this systematic review and meta-analysis was to estimate the global prevalence of dengue-associated myocarditis.

METHODS

A systematic search was conducted utilizing the Cochrane library, PubMed, Scopus, ProQuest, Web of Science, and Preprint servers such as arXiv, medRxiv, bioRxiv, BioRN, ChiRN, ChiRxiv, and SSRN as of November 25, 2022. All primary studies (case series, cross-sectional, retrospective, and prospective) that reported confirmed cases of dengue myocarditis were included. The I2 statistic test assessed the heterogenic characteristics and publication bias was evaluated using Doi plot and Egger regression tests.

RESULTS

A total of 12 studies conducted between 2007 and 2022 with 2795 laboratory-confirmed dengue patients were included. Of the included cases, 502 were positive for myocarditis, with a prevalence of 2.4-78%. The pooled prevalence of dengue-induced myocarditis in the studied population was 21.0% (95% CI, 9 - 38%). The prediction interval was estimated to be 0.00 - 0.81.

CONCLUSION

Myocarditis in dengue patients is a significant and understudied complication in many aspects. To prevent dengue-associated myocarditis, appropriate measures such as early detection of cases and signs, symptoms-based diagnosis via electrocardiography and echocardiography, as well as relevant vector control policies must be implemented.

Dengue beyond fever-fatal dengue myocarditis and complete heart block: A case report and brief overview of cardiac manifestations of dengue fever

Dengue is an endemic viral fever transmitted by mosquitoes that may be asymptomatic or cause a nonspecific flu-like illness. The disease's most severe manifestations are dengue hemorrhagic fever and dengue shock syndrome. Various atypical manifestations have been observed that constitute the expanded dengue syndrome. Although uncommon, it is now known to cause cardiac complications that can be life-threatening and difficult to diagnose. We illustrate a case of a 16-year-old boy infected with dengue who experienced syncope, dizziness, and lethargy. His electrocardiogram showed third degree atrioventricular block which did not resolve with atropine and fluid resuscitation. After excluding all possible causes of complete heart block, transvenous pacing was done. A detailed workup was carried out that favored a diagnosis of subclinical myocarditis leading to complete heart block. The patient did not regain a normal rhythm and was considered for permanent pacemaker implantation. Myocarditis, pericarditis, rhythm disturbances, first- and second-degree atrioventricular blocks, and rarely third-degree heart blocks have been seen in dengue patients. However, a case of dengue illness associated complete heart blocks that is irreversible and necessitates a permanent pacemaker has never been described in the literature, and this is the first such case being reported. This article intends to increase clinicians' awareness, particularly those in dengue-endemic regions, about better recognition and comprehension of cardiac problems associated with dengue fever.

Frequency of pleural effusion in dengue patients by severity, age and imaging modality: a systematic review and meta-analysis

BACKGROUND

Identification of pleural effusion (PE) in dengue infection is an objective measure of plasma leakage and may predict disease progression. However, no studies have systematically assessed the frequency of PE in patients with dengue, and whether this differs across age and imaging modality.

METHODS

We searched Pubmed, Embase Web of Science and Lilacs (period 1900-2021) for studies reporting on PE in dengue patients (hospitalized and outpatient). We defined PE as fluid in the thoracic cavity detected by any imaging test. The study was registered in PROSPERO (CRD42021228862). Complicated dengue was defined as hemorrhagic fever, dengue shock syndrome or severe dengue.

RESULTS

The search identified 2,157 studies of which 85 studies were eligible for inclusion. The studies (n = 31 children, n = 10 adults, n = 44 mixed age) involved 12,800 patients (30% complicated dengue). The overall frequency of PE was 33% [95%CI: 29 to 37%] and the rate of PE increased significantly with disease severity (P = 0.001) such that in complicated vs. uncomplicated dengue the frequencies were 48% and 17% (P < 0.001). When assessing all studies, PE occurred significantly more often in children compared to adults (43% vs. 13%, P = 0.002) and lung ultrasound more frequently detected PE than conventional chest X-ray (P = 0.023).

CONCLUSIONS

We found that 1/3 of dengue patients presented with PE and the frequency increased with severity and younger age. Importantly, lung ultrasound demonstrated the highest rate of detection. Our findings suggest that PE is a relatively common finding in dengue and that bedside imaging tools, such as lung ultrasound, potentially may enhance detection.

Recent outbreak of dengue in Bangladesh: A threat to public health

Background and Aims

The dengue virus is widespread throughout Bangladesh and significantly contributes to morbidity and mortality. One effective method for preventing further dengue epidemics is to reduce mosquito breeding at the most opportune period each year. This study aims to determine dengue prevalence in 2022 by comparing previous years' data and estimating the period of this disease's most significant incidence.

Methods

From the beginning of 2008-December 15, 2022, we looked at the monthly reports of cases made to the Bangladesh Institute of Epidemiology, Disease Control, and Research.

Results

According to our findings, there were 61089 confirmed dengue cases in 2022, with 269 fatalities - the highest annual death toll for this disease since 2000. Almost one-third (32.14%) of all dengue deaths in Bangladesh occurred in 2022 (1 January-15 December), highlighting the severity of the threat posed by this disease in the coming year. Furthermore, we observe that the months in the second half of any year in Bangladesh are the most at risk for dengue transmission. In 2022, Dhaka city and Chittagong are hit the hardest (incidence: 63.07% vs. 14.42%; morality: 63.34% vs. 24.16%), showing the relevance of population density in spreading this fatal disease.

Conclusion

Statistics show an increase in dengue cases every day, and the year 2022 will be marked as the peak of the disease's death prevalence. Both the individuals and the government of Bangladesh need to take action to reduce the dissemination of this epidemic. If not, the country will soon be in great peril.

Association of Neutrophil Mediators With Dengue Disease Severity and Cardiac Impairment in Adults

BACKGROUND

Cardiac impairment contributes to hypotension in severe dengue (SD). However, studies examining pathogenic factors affecting dengue-associated cardiac impairment are lacking. We examined the role of neutrophil mediators on cardiac impairment in clinical dengue.

METHODS

We prospectively enrolled adult patients with dengue and controls. Cardiac parameters were measured using a bioimpedance device. Neutrophils mediators were measured, including myeloperoxidase (MPO) and citrullinated histone H3.

RESULTS

We recruited 107 dengue patients and 30 controls. Patients with dengue were classified according to World Health Organization 2009 guidelines (44 with dengue fever [DF], 51 with DF with warning signs, and 12 with SD). During critical phase, stroke index (P < .001), cardiac index (P = .03), and Granov-Goor index (P < .001) were significantly lower in patients with dengue than in controls. During critical phase, MPO was significantly higher in patients with dengue than in controls (P < .001) and also significantly higher in patients with SD than in those with DF. In addition, MPO was inversely associated with the stroke, cardiac, and Granov-Goor indexes, during the critical phase, and longitudinally as well.

CONCLUSIONS

Cardiac function was decreased, and MPO increased, during with critical phase in patients SD compared with those with DF and controls. MPO may mediate dengue-associated cardiac impairment.

Potential role of transthoracic echocardiography for screening LV systolic dysfunction in patients with a history of dengue infection. A cross-sectional and cohort study and review of the literature

Background

Dengue virus can affect the cardiovascular system and men may be at higher risk of severe complications than women. We hypothesized that clinical dengue virus (DENV) infection could induce myocardial alterations of the left ventricle (LV) and that these changes could be detected by transthoracic echocardiography.

Methodology/Principal findings

We examined individuals from Acre in the Amazon Basin of Brazil in 2020 as part of the Malaria Heart Study. By questionnaires we collected information on self-reported prior dengue infection. All individuals underwent transthoracic echocardiography, analysis of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). We included 521 persons (mean age 40±15 years, 39% men, 50% urban areas) of which 253 (49%) had a history of dengue infection. In multivariable models adjusted for clinical and sociodemographic data, a history of self-reported dengue was significantly associated with lower LVEF (β = -2.37, P < 0.01) and lower GLS (β = 1.08, P < 0.01) in men, whereas no significant associations were found in women (P > 0.05). In line with these findings, men with a history of dengue had higher rates of LV systolic dysfunction (LVEF < 50% = 20%; GLS < 16% = 17%) than those without a history of dengue (LVEF < 50% = 7%; GLS < 16% = 8%; P < 0.01 and 0.06, respectively).

Conclusions/Significance

The findings of this study suggest that a clinical infection by dengue virus could induce myocardial alterations, mainly in men and in the LV, which could be detected by conventional transthoracic echocardiography. Hence, these results highlight a potential role of echocardiography for screening LV dysfunction in participants with a history of dengue infection. Further larger studies are warranted to validate the findings of this study.

Clinical and prognostic relevance of sST2 in adults with dengue-associated cardiac impairment and severe dengue

BACKGROUND

Dengue can be complicated by severe outcomes including cardiac impairment, and the lack of reliable prognostic biomarkers poses a challenge in managing febrile dengue patients. Here, we investigated the functionality of soluble suppressor of tumorigenicity (sST2) as a predictive marker of severe dengue and its association in dengue-associated cardiac impairment.

METHODS

Plasma samples, aged >16 years, collected from 36 dengue fever, 43 dengue with warning signs, 11 severe dengue (collected at febrile, critical and recovery phases) and 30 controls were assayed for plasma levels of sST2, troponin T and N-terminal (NT)-pro hormone brain natriuretic peptide (NT-proBNP) by ELISA. Cardiac parameters: stroke index (SI), cardiac index (CI) and Granov-Goor Index (GGI) were measured with a bioimpedance device during the different phases for dengue subjects and once for the controls.

PRINCIPAL FINDINGS

In the febrile, critical and early recovery phases, sST2 levels were significantly elevated in dengue participants and sST2 levels increased with increasing disease severity (P < 0.01 for all). sST2 concentrations were negatively correlated with SI (r = -0.48; P < 0.001, r = -0.55; P < 0.001), CI (r = -0.26; P = 0.02, r = -0.6: P < 0.001) and GGI (r = -0.44; P < 0.001, r = -0.57; P < 0.001) in the critical and early recovery phases. In contrast, sST2 levels in the febrile and critical phases, were positive correlated to troponin T (r = 0.44, P < 0.001; r = 0.22, P = 0.03, respectively) and NT-proBNP (r = 0.21, P = 0.03; r = 0.35, P < 0.001). ROC analysis demonstrated sST2 as a good biomarker of severe dengue in the critical phase, AUROC 0.79, P < 0.001.

CONCLUSION/SIGNIFICANCE

sST2 levels were elevated in patients with dengue especially in cases of severe dengue. Furthermore, increased sST2 levels were associated with cardiac indicators suggesting lower cardiac performance. While further research is needed to demonstrate its clinical utility, sST2 may be a useful prognostic biomarker of severe dengue.

Cardiovascular sequelae of dengue fever: a systematic review

BACKGROUND

: Dengue is the most important viral diseases globally and a majority of symptomatic infections result in a benign course. However, a small number of patients develop severe manifestations, including myocardial impairment, arrhythmias, and fulminant myocarditis.

AREAS COVERED

This review outlines the incidence of cardiovascular (CV) manifestations of dengue. Electronic databases, including PubMed/MEDLINE, EMBASE, Scopus, and CINAHL were searched for articles incorporating cardiac manifestations of dengue fever (DF).

EXPERT OPINION

: Included studies involved 6,773 patients and 3,122 (46.1%) exhibited at least one cardiac manifestation with DF. Electrocardiogram (ECG) abnormalities (30.6%) included sinus bradycardia (8.8%), non-specific ST-T changes (8.6%), ST depression (7.9%), and T-wave inversion (2.3%). Mechanical sequelae were present in 10.4%, including left ventricular (LV) systolic dysfunction (5.7%), and myocarditis (2.9%). Pericardial involvement was noted as pericarditis (0.1%), pericardial effusion (1.3%), and pericardial tamponade (0.1%). Apart from that, the cardiac injury was depicted through a rise in cardiac enzymes (4.5%). The spectrum of CV manifestations in dengue is broad, ranging from subtle ST-T changes to fulminant myocarditis. This can be a cause of hemodynamic collapse during the critical phase of capillary leakage. Use of contemporary techniques in diagnosing cardiac involvement should be employed for rapid diagnosis and treatment in DF.

Characteristics of hemodynamic parameters after fluid resuscitation and vasoactive drugs administration in pediatric shock: A prospective observational study

Background

Prior studies have shown that septic shock survivors had a normal cardiac index (CI) and systemic vascular resistance index (SVRI). However, this feature seems to be questionable in other-caused shock, since several factors are associated with the hemodynamic profile. This study aims to describe hemodynamic profiles (preload, inotropy, afterload, stroke volume, and cardiac output) after fluid resuscitation and vasoactive therapy in children with shock.

Methods

Children aged 1 month to 18 years old with shock conditions were included in this study. Fluid resuscitation was administered following the American College of Critical Care Medicine (ACCM) protocol. Hemodynamic profiles were assessed at 1 and 6 h from the start of fluid resuscitation. Grouping of the subjects was determined by the USCOM examination in 1st hour until the end of the study and we divided into 3 groups.

Results

At 1 h, group 1 (low CI) was 14% (CI:2.5[1.2–3.2]L/min/m²), group 2 (normal CI) was 66% (CI:4.2[3.4–5.8]L/min/m²), and group 3 (high CI) was 20% (CI:7.1[6.1–9.4]L/min/m²). SVRI was higher in groups 1 and 2 compared to group 3 (p < 0.05). Group 1 and 2 revealed fluid-refractory shock (SVV:25[12–34]% and 29(13–58)%, respectively), lower Smith-Madigan Inotropy Index (SMII) and higher Potential to Kinetic Ratio (PKR) compared to group 3 (p < 0.05). Group 3 revealed fluid-responsive shock (Stroke Volume Variation (SVV):32[18–158]%), higher SMII and lower PKR. At 6th hour, CI in all groups were normal (group 1:3.5[1.2–7.5]; group 2:4.0[1.7–6.1]; group 3:6.0[3.1–6.2]). However, 71.4% and 54.5% of subjects in groups 1 and 2, respectively, still revealed low inotropy. Group 3 revealed a significant increase in SVRI and PKR (p < 0.01).

Conclusions

Most pediatric shock patients were hypodynamic. Even when the CI was normal, the preload, inotropy, and afterload may still be abnormal. It represented the inotropy as a key to hemodynamic.

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Describe the macrocirculation parameter (preload, inotropy, afterload) in children with shock.

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Most pediatric shock tend to be hypodynamic.

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Fluid and vasoactive agent therapy should be guided by combination of the hemodynamic parameters.

Early cardiovascular involvement in dengue fever: A prospective study with two-dimensional speckle tracking echocardiography

Cardiac abnormalities in dengue infection have been conventionally identified by clinical manifestations. The primary objective of our prospective observational study was to assess true cardiovascular involvement and early myocarditis in 150 hospitalised, confirmed cases of dengue fever, through myocardial strain detection using two-dimensional speckle tracking echocardiography. Myocarditis was defined on the basis of European Society of Cardiology (ESC) 2013 criteria. Cardiac biomarkers, namely, creatine phosphokinase myocardial band was elevated in 28.6% and Troponin-T in 23.3% patients. Electrocardiography was abnormal in 64.6% while 6% patients had two-dimensional structural echocardiographic abnormalities. Myocardial dysfunction was suspected in 27.3% based on ESC criteria and strain analysis. The severe dengue group had lower longitudinal strain [−16.4 (6.3)] and circumferential strain [−15.7 (6.7)]. Two-dimensional speckle tracking echocardiography was found to be useful in improving the understanding of early myocardial mechanics in dengue fever.

Morphological Aspects and Viremia Analysis of BALB/c Murine Model Experimentally Infected with Dengue Virus Serotype 4

Ever since its brief introduction in the Brazilian territory in 1981, dengue virus serotype 4 (DENV-4) remained absent from the national epidemiological scenario for almost 25 years. The emergence of DENV-4 in 2010 resulted in epidemics in most Brazilian states. DENV-4, however, remains one of the least studied among the four DENV serotypes. Despite being known as a mild serotype, DENV-4 is associated with severe cases and deaths and deserves to be investigated; however, the lack of suitable experimental animal models is a limiting factor for pathogenesis studies. Here, we aimed to investigate the susceptibility and potential tropism of DENV-4 for liver, lung and heart of an immunocompetent mice model, and to evaluate and investigate the resulting morphological and ultrastructural alterations upon viral infection. BALB/c mice were inoculated intravenously with non-neuroadapted doses of DENV-4 isolated from a human case. The histopathological analysis of liver revealed typical alterations of DENV, such as microsteatosis, edema and vascular congestion, while in lung, widespread areas of hemorrhage and interstitial pneumonia were observed. While milder alterations were present in heart, characterized by limited hemorrhage and discrete presence of inflammatory infiltrate, the disorganization of the structure of the intercalated disc is of particular interest. DENV-4 RNA was detected in liver, lung, heart and serum of BALB/c mice through qRT-PCR, while the NS3 viral protein was observed in all of the aforementioned organs through immunohistochemistry. These findings indicate the susceptibility of the model to the serotype and further reinforce the usefulness of BALB/c mice in studying the many alterations caused by DENV.

Electrocardiographic Changes in Dengue Fever: A Review of Literature

Dengue fever is a prevalent viral disease that primarily affects tropical nations. Although most symptomatic infections have a relatively benign course, a small percentage of patients experience severe clinical symptoms, such as bleeding and endothelial dysfunction, which can lead to hypovolemic shock and cardiovascular collapse. Dengue fever is now known to involve the heart by inducing myocardial inflammation, arrhythmias, and, in rare cases, fulminant myocarditis, up to 13% in severe dengue. Conduction abnormalities can range from benign sinus bradycardia to fulminant tachyarrhythmias and atrioventricular blocks. Although most conduction disturbances are benign and transient, they can occasionally aggravate pre-existing conditions and even be fatal. Unlike other viral myocarditis like hepatitis C induced myocarditis, dengue causes mainly transient changes, and long-term complications like dilated cardiomyopathy are not noted. There is indeed a paucity of data on how to assess and treat individuals with conduction abnormalities. In this review, the authors have discussed the wide variety of conduction abnormalities seen in dengue, their pathophysiology, clinical consequences, and a method for evaluating and managing these individuals.

Cardiac evaluation in adults with dengue virus infection by serial echocardiography

Background

Dengue virus infection (DVI) is a major health problem in many parts of the world. Its manifestations range from asymptomatic infections to severe disease. Although cardiac involvement has been reported in DVI, its incidence has not yet been well established.

Methods

From July 2016 to January 2018, patients hospitalized at the Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Thailand, with dengue virus infection confirmed by positive NS1 or positive dengue immunoglobulin M findings, participated in the study. We characterized the incidence and change in cardiac function by serial echocardiography and levels of troponin-T and creatine kinase-myocardial band (CK-MB) on the day of admission, the day of defervescence, the first day of hypotension (if any), and at 2 week follow-up.

Results

Of the 81 patients evaluated, 6 (7.41%) exhibited elevated biomarker levels. There was no difference in clinical presentation amongst dengue fever, dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), except for the amount of bleeding. Cardiac involvement was found in 22.2% of patients: 3 (3.70%) had left ventricular systolic dysfunction, 3 (3.70%) had transient diastolic dysfunction, 6 (7.41%) had increased levels of at least one cardiac biomarker (troponin-T or CK-MB), and 6 (7.41%) had small pericardial effusion. Myocarditis was suspected in only two patients (with DHF); thus, myocarditis was uncommon in patients with dengue virus infection. Three patients developed DSS during admission and were transferred to the intensive care unit.

Conclusion

Cardiac involvement in adults with dengue infection was common, ranging from elevated cardiac biomarker to myocarditis. Abnormalities in cardiac function had resolved spontaneously by the day of follow-up, without specific treatment. We found that DHF was a significant risk factor for cardiac involvement. Echocardiography is the investigation of choice for evaluating the haemodynamic status of patients with DVI, especially in severe dengue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06639-x.

Knowledge gaps in the epidemiology of severe dengue impede vaccine evaluation

The most severe consequences of dengue virus infection include shock, haemorrhage, and major organ failure; however, the frequency of these manifestations varies, and the relative contribution of pre-existing anti-dengue virus antibodies, virus characteristics, and host factors (including age and comorbidities) are not well understood. Reliable characterisation of the epidemiology of severe dengue first depends on the use of consistent definitions of disease severity. As vaccine trials have shown, severe dengue is a crucial interventional endpoint, yet the infrequency of its occurrence necessitates the inclusion of thousands of study participants to appropriately compare its frequency among participants who have and have not been vaccinated. Hospital admission is frequently used as a proxy for severe dengue; however, lack of specificity and variability in clinical practices limit the reliability of this approach. Although previous infection with a dengue virus is the best characterised risk factor for developing severe dengue, the influence of the timing between dengue virus infections and the sequence of dengue virus infections on disease severity is only beginning to be elucidated. To improve our understanding of the diverse factors that shape the clinical spectrum of disease resulting from dengue virus infection, prospective, community-based and clinic-based immunological, virological, genetic, and clinical studies across a range of ages and geographical regions are needed.

Dengue hemorrhagic fever and cardiac involvement

Dengue viral infection (DVI) is one of the world’s most significant viral infections spreading. Most of the patients have been asymptomatic, with relatively benign clinical manifestations and outcomes. However, a small number of patients have progressed to severe dengue diseases, including hemorrhage, multi-organ impairment, and increased vascular leakage causing hypovolemic shock, which can cause cardiovascular collapse and death. Numerous lines of evidence have demonstrated that DVI could also cause cardiac dysfunction, arrhythmias, and severe myocarditis. The treatment for dengue hemorrhagic fever (DHF) patients remains symptomatic and supportive, with close monitoring of hemodynamic status. The contributory role of cardiac dysfunction in DHF patients has potentially critical implications on the management. This review will address the current knowledge of cardiac involvement in DHF patients and the management strategy to reduce the fatality outcome.

Incidence of Cardiac Manifestations in Children with Dengue Fever: A Cross-sectional Study

OBJECTIVE

The aim of our study was to explore the incidence of cardiac involvement in children with dengue infection admitted in a tertiary care hospital and to evaluate the features of cardiac involvement with the severity of dengue fever.

METHODS

This was a cross-sectional study conducted from September 2014 to August 2016. A total of 130 patients with confirmed dengue NS1 antigen or IgM antibody positivity between the ages of 1 month and 18 years were evaluated. On the third day of admission, blood samples for cardiac markers were collected, and electrocardiograms (ECG) and echocardiograms were performed for each patient.

RESULTS

Of the 130 dengue patients in the study, 60 (46.2%) were males and 70 (53.8%) were females (male to female ratio, 1:1.16). Cardiac involvement was present in 60 (46.2%) children and was more prominent in children with severe dengue (72.7%), followed by dengue with warning symptoms (53.8%) and dengue fever (28.6%). There was no significant correlation between cardiac involvement and primary/secondary dengue. Both ECG and echocardiography changes were significantly correlated with dengue severity, as opposed to cardiac markers.

CONCLUSIONS

Cardiac involvement was present in children with dengue. Evaluation with ECG, echocardiography, and cardiac markers such as creatine phosphokinase-myocardial band (CPK-MB) are required for the management of cardiac complications in children with dengue. Our study showed an association between cardiac involvement and the severity of dengue. Further studies should be framed, and follow-up of dengue patients with cardiac involvement is necessary for therapeutic management.

Causes of death among dengue patients causes of death among hospitalized adults with dengue fever in Tainan, 2015: Emphasis on cardiac events and bacterial infections

INTRODUCTION

The 2015 dengue outbreak in southern Taiwan caused substantial mortality. We analyzed the causes of death among these patients.

MATERIALS AND METHODS

This retrospective study was conducted at a medical center in Tainan from August 2015 to December 2015. Dengue was diagnosed based on the detection of serum dengue NS1 antigen, IgM, or viral RNA in the blood. Causes of death were retrieved from chart reviews by three clinicians.

RESULTS

There were 4488 cases of dengue in the study hospital, with an in-hospital fatality rate of 1.3% (60 cases). The mean age of the 60 fatal cases was 73 years, among whom 90% were aged ≥65 years. Twenty-eight (46.7%) patients died of severe dengue, and 29 (48.3%) deaths were possibly related to dengue. Of the latter, 24 (40%) died of secondary infections. Thirteen cardiac arrest events, including out-of-hospital (5 events) and in-hospital (8) cardiac arrests in the emergency department, occurred during the dengue epidemic. Seven (53.8%) patients did not receive medical aid before the event. Of the 40 deaths that occurred within one week after hospitalization, 60% died of severe dengue. In contrast, 50% of 20 deaths that occurred one week after hospitalization were related to hospital-acquired infections, mainly pneumonia.

CONCLUSION

Of 60 fatal cases, with a predominance of elderly patients, deaths were related to severe dengue within the first week after admission and secondary infections thereafter. The absence of medical care before cardiac arrest events highlights the importance of health education for warning signs of dengue.

Cardiovascular disorders in hospitalized patients with dengue infection

INTRODUCTION

Cardiac complications in dengue patients are not uncommon and are not diagnosed, since they are usually mild and self-limiting.

OBJECTIVES

To characterize the cardiovascular manifestations in hospitalized patients with dengue infection.

METHODS

We conducted an observational, analytical, longitudinal, prospective epidemiological study, which included 427 patients treated at Manuel Fajardo Clinical-Surgical Teaching Hospital with diagnosis of dengue infection since April 2017 to April 2018.

RESULTS

Cardiovascular manifestations (19.7%), mainly heart rate disorders (sinus bradycardia [13.8%], atrial [4.9%] and ventricular [4.0%] extrasystoles) were frequent in dengue infection patients. Pericarditis and myocarditis were diagnosed in 1.6% and 0.2% respectively. These disorders were self-limiting in 83.3% of cases and occurred in the first days of the onset of fever in 75.0%. Advanced age (OR=1.70), male sex (OR=1.94), decreased platelet count (OR=1.13) and dengue with warning signs (OR=3.29) were related to a higher probability of presenting cardiovascular disorders in the course of a dengue infection.

CONCLUSIONS

Cardiovascular manifestations in dengue patients are frequent, and are related to advanced age, male sex, as well as severe forms of the disease.

Myocarditis Prevalence in Paediatric Dengue Infection: A Prospective Study in Tertiary Hospital in Yogyakarta, Indonesia

Awareness of cardiac involvement in dengue infection has potentially valuable management implications. To determine the prevalence of myocarditis in dengue severity, we conducted prospective study of paediatric dengue illness at Dr. Sardjito General Hospital, a tertiary hospital in Yogyakarta, Indonesia, from period of July 2015 to May 2016. World Health Organization (WHO) Dengue Guideline 2011 classification system was used. Diagnosis of dengue infection was made based on either by dengue serology and/or NS1 test. Myocarditis was assessed based on elevation of cardiac enzymes, as creatine kinase (CK), creatine kinase-MB (CK-MB), Troponin I (TnI) and by electrocardiography (ECG). Proportion between groups was compared using the Fisher's exact test. We analysed 50 children with diagnosis of dengue fever (DF), 12 of dengue haemorrhagic fever (DHF) and 23 of dengue shock syndrome (DSS). Myocarditis diagnosed in 53%, 75% and 96% of DF, DHF and DSS, respectively. We found that myocarditis was more prevalent significantly in DSS than DF (p = 0.003).

Beyond thrombocytopaenia, haemorrhage and shock: the expanded dengue syndrome

Dengue infection classically presents with fever, thrombocytopaenia, and varying degrees of plasma leakage, giving rise to shock. However, a myriad of other manifestations, involving the cardiovascular system, the nervous system, the liver, the kidneys, the gut and the haematological system have been reported in dengue. This review summarizes these varied presentations.

Case Report: Right Hemispheric Neuroimaging Abnormalities in a Patient with Dengue Encephalopathy

Dengue encephalitis and dengue encephalopathy are frequent neurological complications of systemic dengue virus infection. Neuroimaging is normal in approximately 50% of patients. Common imaging abnormalities involve periventricular structures, including the basal ganglion, thalamus, and periventricular white matter. We describe an unusual case of dengue encephalopathy with unilateral imaging abnormalities involving the right cerebral hemisphere and mimicking the involvement of the right middle cerebral artery.

Development of standard clinical endpoints for use in dengue interventional trials

Dengue is a major public health problem worldwide. Although several drug candidates have been evaluated in randomized controlled trials, none has been effective and at present, early recognition of severe dengue and timely supportive care are used to reduce mortality. While the first dengue vaccine was recently licensed, and several other candidates are in late stage clinical trials, future decisions regarding widespread deployment of vaccines and/or therapeutics will require evidence of product safety, efficacy and effectiveness. Standard, quantifiable clinical endpoints are needed to ensure reproducibility and comparability of research findings. To address this need, we established a working group of dengue researchers and public health specialists to develop standardized endpoints and work towards consensus opinion on those endpoints. After discussion at two working group meetings and presentations at international conferences, a Delphi methodology-based query was used to finalize and operationalize the clinical endpoints. Participants were asked to select the best endpoints from proposed definitions or offer revised/new definitions, and to indicate whether contributing items should be designated as optional or required. After the third round of inquiry, 70% or greater agreement was reached on moderate and severe plasma leakage, moderate and severe bleeding, acute hepatitis and acute liver failure, and moderate and severe neurologic disease. There was less agreement regarding moderate and severe thrombocytopenia and moderate and severe myocarditis. Notably, 68% of participants agreed that a 50,000 to 20,000 mm³ platelet range be used to define moderate thrombocytopenia; however, they remained divided on whether a rapid decreasing trend or one platelet count should be case defining. While at least 70% agreement was reached on most endpoints, the process identified areas for further evaluation and standardization within the context of ongoing clinical studies. These endpoints can be used to harmonize data collection and improve comparability between dengue clinical trials.

Dengue is a major public health problem worldwide. Although several drug candidates have been evaluated in randomized controlled trials, none has been effective, and early recognition of severe dengue and timely supportive care remain the only means to reduce mortality. While the first dengue vaccine was recently licensed, and several other candidates are in late stage clinical trials, future decisions regarding deployment of such vaccines or therapeutics will require evidence of product safety, efficacy and effectiveness. Standard, quantifiable clinical endpoints are needed to ensure reproducibility and comparability of research findings. To address this need, we established a working group of dengue researchers, vaccine developers, and public health specialists to develop endpoints. After two working group meetings and discussions at international meetings, the Delphi methodology was used to clarify and further develop endpoints such that 70% or greater agreement was reached on most endpoint definitions including moderate and severe plasma leakage, moderate and severe bleeding, acute hepatitis and acute liver failure, and moderate and severe neurologic disease. The process identified areas for further evaluation and standardization within the context of ongoing clinical studies. The endpoints can be used to harmonize data collection and improve comparability between dengue clinical trials.

Critical care for dengue in adult patients: an overview of current knowledge and future challenges

PURPOSE OF REVIEW

This review aims to update and summarize the current knowledge about clinical features, management, and risk factors of adult dengue patients requiring intensive care with consequently higher risk of mortality.

RECENT FINDINGS

Increasingly, there are more adult dengue patients who require intensive care. This may be due to a shift in epidemiology of dengue infection from mainly a pediatric disease toward adult disease. In addition, multiorgan dysfunction was observed to be a key risk factor for ICU admission and mortality. This may be due to older adults having preexisting comorbidities that potentially predispose to have multiple severe organ impairment. Interventions remain largely supportive but also require more evidence-based trials and treatment protocols.

SUMMARY

These findings highlight the common clinical manifestations of adult dengue patients and the challenges of clinical management in ICU. Risk factors for prediction of adult dengue patients who require ICU are available, but they lack validation and consistent study design for meta-analysis in future. Early recognition of these risk factors, with close monitoring and prompt clinical management, remains critical to reduce mortality.

Experimental in vitro and in vivo systems for studying the innate immune response during dengue virus infections

Dengue is the most prevalent arboviral disease in humans and leads to significant morbidity and socioeconomic burden in tropical and subtropical areas. Dengue is caused by infection with any of the four closely related serotypes of dengue virus (DENV1-4) and usually manifests as a mild febrile illness, but may develop into fatal dengue hemorrhagic fever and shock syndrome. There are no specific antiviral therapies against dengue because understanding of DENV biology is limited. A tetravalent chimeric dengue vaccine, Dengvaxia, has finally been licensed for use, but its efficacy was significantly lower against DENV-2 infections and in dengue-naïve individuals. The identification of mechanisms underlying the interactions between DENV and immune responses will help to determine efficient therapeutic and preventive options. It has been well established how the innate immune system responds to DENV infection and how DENV overcomes innate antiviral defenses, however further progress in this field remains hampered by the absence of appropriate experimental dengue models. Herein, we review the available in vitro and in vivo approaches to study the innate immune responses to DENV.

Cardio-haemodynamic assessment and venous lactate in severe dengue: Relationship with recurrent shock and respiratory distress

Background

Dengue can cause plasma leakage that may lead to dengue shock syndrome (DSS). In approximately 30% of DSS cases, recurrent episodes of shock occur. These patients have a higher risk of fluid overload, respiratory distress and poor outcomes. We investigated the association of echocardiographically-derived cardiac function and intravascular volume parameters plus lactate levels, with the outcomes of recurrent shock and respiratory distress in severe dengue.

Methods/Principle findings

We performed a prospective observational study in Paediatric and adult ICU, at the Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam. Patients with dengue were enrolled within 12 hours of admission to paediatric or adult ICU. A haemodynamic assessment and portable echocardiograms were carried out daily for 5 days from enrolment and all interventions recorded.

102 patients were enrolled; 22 patients did not develop DSS, 48 had a single episode of shock and 32 had recurrent shock. Patients with recurrent shock had a higher enrolment pulse than those with 1 episode or no shock (median: 114 vs. 100 vs. 100 b/min, P = 0.002), significantly lower Stroke Volume Index (SVI), (median: 21.6 vs. 22.8 vs. 26.8mls/m², P<0.001) and higher lactate levels (4.2 vs. 2.9 vs. 2.2 mmol/l, P = 0.001). Higher SVI and worse left ventricular function (higher Left Myocardial Performance Index) on study days 3–5 was associated with the secondary endpoint of respiratory distress. There was an association between the total IV fluid administered during the ICU admission and respiratory distress (OR: 1.03, 95% CI 1.01–1.06, P = 0.001). Admission lactate levels predicted patients who subsequently developed recurrent shock (P = 0.004), and correlated positively with the total IV fluid volume received (rho: 0.323, P = 0.001) and also with admission ALT (rho: 0.764, P<0.001) and AST (rho: 0.773, P<0.001).

Conclusions/Significance

Echo-derived intravascular volume assessment and venous lactate levels can help identify dengue patients at high risk of recurrent shock and respiratory distress in ICU. These findings may serve to, not only assist in the management of DSS patients, but also these haemodynamic endpoints could be used in future dengue fluid intervention trials.

Dengue is a viral illness that can lead to severe and potentially fatal complications. The most common complication is fluid leakage from blood vessels, which can cause low blood pressure or dengue shock syndrome (DSS). The majority of patients recover with simple intravenous fluid replacement, however in approximately 30% of DSS cases, recurrent episodes of shock occur, and these patients have a higher risk of fluid overload, respiratory distress and death. We investigated whether using portable echocardiograms (Echo) in the intensive care unit (ICU) to assess cardiac function and intravascular volume parameters as well as blood lactate levels, can help identify these patients. We found patients who developed recurrent shock had higher heart rates and lower Stroke Volume Index (SVI), and higher lactate levels at enrolment than those with 1 episode or no shock. Higher SVI and worse cardiac function after 3 days in ICU was associated with respiratory distress. Admission lactate levels predicted patients who subsequently developed recurrent shock and correlated positively with the total IV fluid volume received. These results demonstrate that Echo-derived intravascular volume assessment and venous lactate levels can help identify dengue patients at high risk of poor outcomes in the ICU, and could assist in the management of severe dengue.

Dengue infection

Dengue is widespread throughout the tropics and local spatial variation in dengue virus transmission is strongly influenced by rainfall, temperature, urbanization and distribution of the principal mosquito vector Aedes aegypti. Currently, endemic dengue virus transmission is reported in the Eastern Mediterranean, American, South-East Asian, Western Pacific and African regions, whereas sporadic local transmission has been reported in Europe and the United States as the result of virus introduction to areas where Ae. aegypti and Aedes albopictus, a secondary vector, occur. The global burden of the disease is not well known, but its epidemiological patterns are alarming for both human health and the global economy. Dengue has been identified as a disease of the future owing to trends toward increased urbanization, scarce water supplies and, possibly, environmental change. According to the WHO, dengue control is technically feasible with coordinated international technical and financial support for national programmes. This Primer provides a general overview on dengue, covering epidemiology, control, disease mechanisms, diagnosis, treatment and research priorities.

Dynamic Measurement of Hemodynamic Parameters and Cardiac Preload in Adults with Dengue: A Prospective Observational Study

Few previous studies have monitored hemodynamic parameters to determine the physiological process of dengue or examined inferior vena cava (IVC) parameters to assess cardiac preload during the clinical phase of dengue. From January 2013 to July 2015, we prospectively studied 162 hospitalized adults with confirmed dengue viral infection using non-invasive cardiac output monitoring and bedside ultrasonography to determine changes in hemodynamic and IVC parameters and identify the types of circulatory shock that occur in patients with dengue. Of 162 patients with dengue, 17 (10.5%) experienced dengue shock and 145 (89.5%) did not. In patients with shock, the mean arterial pressure was significantly lower on day 6 after fever onset (P = 0.045) and the pulse pressure was significantly lower between days 4 and 7 (P<0.05). The stroke volume index and cardiac index were significantly decreased between days 4 and 15 and between days 5 and 8 after fever onset (P<0.05), respectively. A significant proportion of patients with dengue shock had an IVC diameter <1.5 cm and IVC collapsibility index >50% between days 4 and 5 (P<0.05). Hypovolemic shock was observed in 9 (52.9%) patients and cardiogenic shock in 8 (47.1%), with a median (interquartile range) time to shock onset of 6.0 (5.0–6.5) days after fever onset, which was the median day of defervescence. Intravascular hypovolemia occurred before defervescence, whereas myocardial dysfunction occurred on the day of defervescence until 2 weeks after fever onset. Hypovolemic shock and cardiogenic shock each occurred in approximately half of the patients with dengue shock. Therefore, dynamic measures to estimate changes in hemodynamic parameters and preload should be monitored to ensure adequate fluid therapy among patients with dengue, particularly patients with dengue shock.

Evaluation of Cardiac Involvement in Children with Dengue by Serial Echocardiographic Studies

Background

Infection with dengue virus results in a wide range of clinical manifestations from dengue fever (DF), a self-limited febrile illness, to dengue hemorrhagic fever (DHF) which is characterized by plasma leakage and bleeding tendency. Although cardiac involvement has been reported in dengue, the incidence and the extent of cardiac involvement are not well defined.

Methods and Principal findings

We characterized the incidence and changes in cardiac function in a prospective in-patient cohort of suspected dengue cases by serial echocardiography. Plasma leakage was detected by serial chest and abdominal ultrasonography. Daily cardiac troponin-T levels were measured. One hundred and eighty one dengue cases were enrolled. On the day of enrollment, dengue cases that already developed plasma leakage had lower cardiac index (2695 (127) vs 3188 (75) (L/min/m²), p = .003) and higher left ventricular myocardial performance index (.413 (.021) vs .328 (.026), p = .021) and systemic vascular resistance (2478 (184) vs 1820 (133) (dynes·s/cm⁵), p = .005) compared to those without plasma leakage. Early diastolic wall motion of the left ventricle was decreased in dengue cases with plasma leakage compared to those without. Decreased left ventricular wall motility was more common in dengue patients compared to non-dengue cases particularly in cases with plasma leakage. Differences in cardiac function between DF and DHF were most pronounced around the time of plasma leakage. Cardiac dysfunction was transient and did not require treatment. Transient elevated troponin-T levels were more common in DHF cases compared to DF (14.5% vs 5%, p = 0.028).

Conclusions

Transient left ventricular systolic and diastolic dysfunction was common in children hospitalized with dengue and related to severity of plasma leakage. The functional abnormality spontaneously resolved without specific treatment. Cardiac structural changes including myocarditis were uncommon.

Dengue is a viral infection with a wide range of symptoms from a self-limiting fever called dengue fever (DF) to dengue hemorrhagic fever (DHF) which is characterized by leaky blood vessels and bleeding that can lead to shock in severe cases. Abnormal heart function has been reported but the frequencies and the progression of heart involvement are not well defined. In this study children with dengue had serial evaluation of their heart function during the course of the illness. Patients with DHF had comparatively low blood volume at the time of fever resolution and had decreased blood flow into the left lower heart chamber compared to DF cases. Relaxation and contraction of the left side of the heart were also relatively decreased in DHF. These abnormalities may contribute to the clinical response and complications of fluid replacement in dengue.

Dengue in adults admitted to a referral hospital in Hanoi, Vietnam

Knowledge of adult dengue virus (DENV) infection from Hanoi, Vietnam, is limited. In 2008, we prospectively studied 143 (77 male) confirmed (nonstructural 1 antigen enzyme-linked immunosorbent assay [ELISA], DENV polymerase chain reaction, paired serology) adult dengue patients of median age 23.5 (range 16-72) years. They were admitted to the National Hospital for Tropical Diseases, Hanoi, on median illness day (D) 5 (range 1-8). By D8, 141 (98.6%) were afebrile. Platelet counts and hematocrit (median, interquartile range [IQR]) nadired and peaked on D5 and D4, respectively: 40,000/μL (10,000-109,000/μL), 43.4% (34.9-49.7%). Four (2.8%) patients had severe dengue: 1) D10 shock (N = 1) and 2) aspartate aminotransferase (AST) ≥ 1,000 IU/L (N = 3, D5 and D7). Of 143 patients, 118 (82.5%) had ≥ 1 warning sign (World Health Organization [WHO] 2009 criteria): mucosal bleeding 66/143 (46.1%), soft tissue edema 54/143 (37.7%), and ultrasound detected plasma leakage (pleural effusions/ascites) 30/129 (23.25%). 138 (96.5%) patients received intravenous (IV) fluids: 3 L (IQR: 0.5-8.5 L). Most patients had non-severe dengue with warning signs. High rates of edema and plasma leakage may be explained partly by liberal use of IV fluids. Studies are needed on optimizing fluid management in non-severe adult dengue.

Clinical implications and treatment of dengue

Dengue is a common pathogenic disease often proving fatal, more commonly affecting the tropics. Aedes mosquito is the vector for this disease, and outbreaks of dengue often cause mass damage to life. The current review is an effort to present an insight into the causes, etiology, symptoms, transmission, diagnosis, major organs affected, mitigation and line of treatment of this disease with special emphasis on drugs of natural origin. The disease has a potential to spread as an endemic, often claiming several lives and thus requires concerted efforts to work out better treatment options. Traditional medicine offers an alternative solution and could be explored as a safer treatment option. Development of a successful vaccine and immunization technique largely remains a challenge and a better antiviral approach needs to be worked out to complement the supportive therapy. No single synthetic molecule has found to be wholly effective enough to offer curative control and the line of treatment mostly utilizes a combination of fluid replacement and antipyretics-analgesics like molecules to provide symptomatic relief.

Predicting outcome from dengue

Dengue is emerging as one of the most abundant vector-borne disease globally. Although the majority of infections are asymptomatic or result in only a brief systemic viral illness, a small proportion of patients develop potentially fatal complications. These severe manifestations, including a unique plasma leakage syndrome, a coagulopathy sometimes accompanied by bleeding, and organ impairment, occur relatively late in the disease course, presenting a window of opportunity to identify the group of patients likely to progress to these complications. However, as yet, differentiating this group from the thousands of milder cases seen each day during outbreaks remains challenging, and simple and inexpensive strategies are urgently needed in order to improve case management and to facilitate appropriate use of limited resources. This review will cover the current understanding of the risk factors associated with poor outcome in dengue. We focus particularly on the clinical features of the disease and on conventional investigations that are usually accessible in mid-level healthcare facilities in endemic areas, and then discuss a variety of viral, immunological and vascular biomarkers that have the potential to improve risk prediction. We conclude with a description of several novel methods of assessing vascular function and intravascular volume status non-invasively.

Cardiovascular manifestations of the emerging dengue pandemic

Dengue is one of the most important emerging viral diseases globally. The majority of symptomatic infections result in a relatively benign disease course. However, a small proportion of patients develop severe clinical manifestations, including bleeding, organ impairment, and endothelial dysfunction with increased capillary permeability causing hypovolaemic shock that can lead to cardiovascular collapse. Evidence is increasing that dengue can also cause myocardial impairment, arrhythmias and, occasionally, fulminant myocarditis. No antiviral agents or vaccines are licensed for dengue, and treatment remains supportive with judicious fluid replacement for patients with severe disease. Defining the role of cardiac dysfunction in the haemodynamic compromise of severe dengue has potentially important management implications. In this Review, we will outline the current understanding of the cardiovascular manifestations of dengue, including myocardial and vascular involvement, and conclude with a discussion of the available therapeutic options and potential future research directions.

Heart rate variability in patients being treated for dengue viral infection: new insights from mathematical correction of heart rate

INTRODUCTION

Severe dengue hemorrhagic fever (DHF) is a viral infection that acts to increase permeability of capillaries, resulting in internal hemorrhage. Linear frequency domain Fourier spectral analysis represents the most published noninvasive tool for diagnosing and assessing health status via calculated heart rate variability (HRV). As such, HRV may be useful in assessing clinical status in DHF patients, but is prone to erroneous results and conclusions due to the influence of the average HR during the time period of HRV assessment (defined as the "prevailing" HR). We tested the hypothesis that alterations in HRV calculated with linear frequency analysis would be minimal when mathematically corrected for prevailing HR following dengue viral infection.

METHODS

Male (N = 16) and female (N = 11) patients between the ages of 6 months and 15 years of age (10 ± 6 SD years) were tracked through the progression of the dengue viral infection with treatment following the abatement of a fever (defervescence). Electrocardiographic recordings were collected and analyzed for HRV.

RESULTS

High frequency (HF), low frequency (LF), and LF/HF ratio were unaffected by correction for prevailing HR.

CONCLUSION

HRV corrected for changes in HR did not alter the interpretation of our data. Therefore, we conclude that cardiac parasympathetic activity (based on HF frequency) is responsible for the majority of the HR reduction following defervescence in patients with dengue viral infection.

Dengue: Moving from Current Standard of Care to State-of-the-Art Treatment

Treatment of dengue remains supportive in the absence of targeted antiviral therapy or approved vaccines. Responsive fluid management is key to preventing progression to shock or other severe manifestations. The dynamic natural history of dengue infection and its influence on hemodynamic homeostasis needs to be carefully considered in the planning of individualized therapy. Though largely self-limiting, the sheer burden of dengue disease on the global population will result in atypical manifestations especially in children, older adults, and comorbid patients. Management of these has not yet been systematized. The failure of recent randomized controlled trials to show utility for antiviral and immunomodulatory agents in dengue is disappointing. Vaccine candidates hold promise, but growing outbreaks require more robust, evidence-based management guidelines to inform clinicians, especially in novel epidemic situations.

Clinical characteristics of Dengue shock syndrome in Vietnamese children: a 10-year prospective study in a single hospital

BACKGROUND

Dengue shock syndrome (DSS) is a severe manifestation of dengue virus infection that particularly affects children and young adults. Despite its increasing global importance, there are no prospective studies describing the clinical characteristics, management, or outcomes of DSS.

METHODS

We describe the findings at onset of shock and the clinical evolution until discharge or death, from a comprehensive prospective dataset of 1719 Vietnamese children with laboratory-confirmed DSS managed on a single intensive care unit between 1999 and 2009.

RESULTS

The median age of patients was 10 years. Most cases had secondary immune responses, with only 6 clear primary infections, and all 4 dengue virus serotypes were represented during the 10-year study. Shock occurred commonly between days 4 and 6 of illness. Clinical signs and symptoms were generally consistent with empirical descriptions of DSS, although at presentation 153 (9%) were still febrile and almost one-third had no bleeding. Overall, 31 (2%) patients developed severe bleeding, primarily from the gastrointestinal tract, 26 of whom required blood transfusion. Only 8 patients died, although 123 of 1719 (7%) patients had unrecordable blood pressure at presentation and 417 of the remaining 1596 (26%) were hypotensive for age. The majority recovered well with standard crystalloid resuscitation or following a single colloid infusion. All cases were classified as severe dengue, while only 70% eventually fulfilled all 4 criteria for the 1997 World Health Organization classification of dengue hemorrhagic fever.

CONCLUSIONS

With prompt intervention and assiduous clinical care by experienced staff, the outcome of this potentially fatal condition can be excellent.

Left ventricular myocardial performance in patients with dengue hemorrhagic fever and thrombocytopenia as assessed by two-dimensional speckle tracking echocardiography

OBJECTIVES

We obtained longitudinal, radial and circumferential strains in patients with dengue hemorrhagic fever (DhF) and thrombocytopenia using two-dimensional (2D) speckle tracking echocardiography to analyze left ventricular (LV) myocardial performance.

METHODS

In this prospective study, 2D echocardiographic images of the left ventricle in the four-, three- and two-chamber views and parasternal short-axis views at the basal, mid and apical levels were obtained in 40 subjects: 20 patients (23 ± 8 years, 12 male) with DhF and thrombocytopenia and 20 healthy controls (23 ± 5 years, 11 male). Of the 20 patients, imaging was performed again in 19 at discharge after a hospital stay of 8 ± 1 days. Longitudinal, circumferential and radial strains were quantified and compared in an 18-segment model using a novel speckle tracking system.

RESULTS

Left ventricular global ejection fraction was reduced in patients with DhF at presentation as compared with controls (51.25 ± 0.96% vs. 59.32 ± 1.26%; p = 0.032). Peak longitudinal strain in patients with DhF was significantly attenuated in the subendocardial region compared with normal controls (p < 0.001). A significant increase in circumferential strain for patients with DhF was evident only in the subepicardial region (p = 0.009). Patients with DhF showed significantly higher radial strain than controls (p < 0.001). On multivariate analysis, subendocardial longitudinal strain independently predicted the duration of hospital stay in patients with DhF.

CONCLUSION

Assessment of speckle tracking echocardiography-derived LV mechanics helps in understanding myocardial mechanics in patients with DhF and thrombocytopenia. Identification of reduced LV longitudinal strain helps in understanding the mechanism of reduced LV myocardial performance seen in patients with DhF.

Dengue myocarditis in Singapore: two case reports

The authors report two cases of complicated dengue viral infection with acute myocarditis involving young male adults, of which one was fatal. The first case presented with typical signs of myocardial disease: chest pain and diaphoresis with myocardial depression in the electrocardiograph. The second case deteriorated rapidly and demised within the first day of admission. Histology of the heart muscles showed multiple small foci of myocyte necrosis surrounded by lymphocytes, in keeping with viral myocarditis. Both cases fulfilled the World Health Organization (WHO) diagnosis of probable dengue: the first case had positive dengue serology, both IgM and IgG at day six of illness, and the second case was polymerase chain reaction (PCR) positive for dengue and identified as serotype 2. Despite the severe outcome, both cases did not completely fulfil the criteria for dengue haemorrhagic fever (DHF). Although severe cardiac impairment is not commonly reported in dengue infection, it can be life threatening.