Assessing the prognosis of dengue-infected patients

A modified Sequential Organ Failure Assessment score for dengue: development, evaluation and proposal for use in clinical trials

Background

Dengue is a neglected tropical disease, for which no therapeutic agents have shown clinical efficacy to date. Clinical trials have used strikingly variable clinical endpoints, which hampers reproducibility and comparability of findings. We investigated a delta modified Sequential Organ Failure Assessment (delta mSOFA) score as a uniform composite clinical endpoint for use in clinical trials investigating therapeutics for moderate and severe dengue.

Methods

We developed a modified SOFA score for dengue, measured and evaluated its performance at baseline and 48 h after enrolment in a prospective observational cohort of 124 adults admitted to a tertiary referral hospital in Vietnam with dengue shock. The modified SOFA score included pulse pressure in the cardiovascular component. Binary logistic regression, cox proportional hazard and linear regression models were used to estimate association between mSOFA, delta mSOFA and clinical outcomes.

Results

The analysis included 124 adults with dengue shock. 29 (23.4%) patients required ICU admission for organ support or due to persistent haemodynamic instability: 9/124 (7.3%) required mechanical ventilation, 8/124 (6.5%) required vasopressors, 6/124 (4.8%) required haemofiltration and 5/124 (4.0%) patients died. In univariate analyses, higher baseline and delta (48 h) mSOFA score for dengue were associated with admission to ICU, requirement for organ support and mortality, duration of ICU and hospital admission and IV fluid use.

Conclusions

The baseline and delta mSOFA scores for dengue performed well to discriminate patients with dengue shock by clinical outcomes, including duration of ICU and hospital admission, requirement for organ support and death. We plan to use delta mSOFA as the primary endpoint in an upcoming host-directed therapeutic trial and investigate the performance of this score in other phenotypes of severe dengue in adults and children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07705-8.

Coagulopathy of Dengue and COVID-19: Clinical Considerations

Thrombocytopenia and platelet dysfunction commonly occur in both dengue and COVID-19 and are related to clinical outcomes. Coagulation and fibrinolytic pathways are activated during an acute dengue infection, and endothelial dysfunction is observed in severe dengue. On the other hand, COVID-19 is characterised by a high prevalence of thrombotic complications, where bleeding is rare and occurs only in advanced stages of critical illness; here thrombin is the central mediator that activates endothelial cells, and elicits a pro-inflammatory reaction followed by platelet aggregation. Serological cross-reactivity may occur between COVID-19 and dengue infection. An important management aspect of COVID-19-induced immunothrombosis associated with thrombocytopenia is anticoagulation with or without aspirin. In contrast, the use of aspirin, nonsteroidal anti-inflammatory drugs and anticoagulants is contraindicated in dengue. Mild to moderate dengue infections are treated with supportive therapy and paracetamol for fever. Severe infection such as dengue haemorrhagic fever and dengue shock syndrome often require escalation to higher levels of support in a critical care facility. The role of therapeutic platelet transfusion is equivocal and should not be routinely used in patients with dengue with thrombocytopaenia and mild bleeding. The use of prophylactic platelet transfusion in dengue fever has strained financial and healthcare systems in endemic areas, together with risks of transfusion-transmitted infections in low- and middle-income countries. There is a clear research gap in the management of dengue with significant bleeding.

Dengue Virus

Dengue virus (DENV) belongs to the family Flaviviridae, genus Flavivirus. It is a single-stranded positive-sense ribonucleic acid virus with 10,700 bases. The genus Flavivirus includes other arthropod borne viruses such as yellow fever virus, West Nile virus, Zika virus, tick-borne encephalitis virus. It infects ~50–200 million people annually, putting over 3.6 billion people living in tropical regions at risk and causing ~20,000 deaths annually. The expansion of dengue is attributed to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement, and also viral evolution. There are four antigenically different serotypes of DENV based on the differences in their viral structural and nonstructural proteins. DENV infection causes a spectrum of illness ranging from asymptomatic to dengue fever to severe dengue shock syndrome. Infection with one serotype confers lifelong immunity against that serotype, but heterologus infection leads to severe dengue hemorrhagic fever due to antibody-dependent enhancement. Diagnosis of dengue infections is based mainly on serological detection of either antigen in acute cases or antibodies in both acute and chronic infection. Viral detection and real-time PCR detection though helpful is not feasible in resource poor setup. Treatment of dengue depends on symptomatic management along with fluid resuscitation and may require platelet transfusion. Although vaccine development is in late stages of development, developing a single vaccine against four serotypes often causes serious challenges to researchers; hence, the main stay of prevention is vector control and management.

Expression Pattern of Selected Toll-like Receptors (TLR's) in the PBMC's of Severe and Non-severe Dengue Cases

Objective: The role of TLR's in the pathogenesis of dengue is not explored well. Differential expression of TLR2 and TLR4 was reported in dengue cases. In the present study in order to understand the expression pattern of various TLR's, including TLR2, TLR3, TLR4 and TLR9, mRNA levels were determined in various dengue study groups compared to control groups, at the time of admission and around defervescence using quantitative real-time PCR (RT-PCR).Methods: A total of 88 dengue cases with 32 severe and 56 non-severe cases were involved in the study. Gene expression pattern of the study groups was compared with 31 other febrile illness (OFI) cases and 63 healthy controls. Transcript levels of the target genes were estimated from the peripheral blood mononuclear cells (PBMC) samples collected from cases and controls using quantitative real-time PCR.Results: We have noted a significant alteration in the levels of all TLR's in dengue and OFI cases compared to healthy controls at the time of admission. Interestingly we have noted a significant alteration in the levels of TLR9 in severe and non-severe cases during defervescence. The same was not detected in the OFI group.Conclusion: The present study found a change in TLR's during dengue infection. This suggests us to explore the TLR's as therapeutic candidate for anti-dengue virus strategies. However, in order to ascertain the involvement of TLR's in the disease pathology and its role as biomarkers for prognosis, a complete dynamics of TLR's expression needs to be studied.

Dengue haemorrhagic fever: An emerging disease in Nigeria, West Africa

INTRODUCTION

In Nigeria, dengue fever caused by dengue virus, types 1 and 2 has been diagnosed for many years. Although, seroepidemiological surveys have shown that dengue virus activity is, widespread in the country, there is scanty information on dengue, hemorrhagic fever with little attention paid to dengue fever largely, because it presents as classical dengue fever characterized by fever, myalgia, headache, arthralgia, retro-orbital pain, gastro intestinal, symptoms and skin rash. We are updating the current information of dengue, in Nigeria, as well as DHF which is an emerging disease in the west, African country.

METHODS

PUBMED, Google scholar, cross-reference databases and individual publications not publicly archived were used. All available literature on, dengue from Nigeria were identified.

RESULTS

Dengue virus 3 and 4 have been recently detected in Nigeria, with the emergence of dengue haemorrhagic fever for the first time. Poor, surveillance, underreporting, and misdiagnosis of the disease as malaria, are major problems.

CONCLUSION

Priority must be given to increasing surveillance activity to, detect more dengue haemorrhagic fever cases and determine the magnitude, of the dengue problem. It is important to enhance the capacity of, laboratories to diagnose dengue haemorrhagic fever by providing them with, modern equipment, reagents and new infrastructure.

Differential expression of NADPH oxidase-2 (Nox-2) and nuclear factor-erythroid 2-related factor 2 (Nrf2) transcripts in peripheral blood mononuclear cells isolated from dengue patients

The role of oxidative stress in the pathogenesis of dengue infection is not completely known. A recent study reveals the involvement of oxidative stress responsive molecules in the generation of host immune responses to dengue virus in vitro. Objective of the present study was to analyse the changes in the expression of oxidant-antioxidant genes Nox-2 (NADPH oxidase) and Nrf2 (nuclear factor-erythroid 2-related factor 2) in patients with dengue during the early phase of infection compared to other febrile illness (OFI) cases and healthy controls using Real-time qPCR assay. The study enrolled 88 dengue patients, 31 OFI cases, and 63 healthy individuals as controls. Out of 88 dengue cases, 32 were classified as severe dengue cases (SD) and remaining 56 patients as non-severe dengue (NSD). Blood samples were collected firstly at the time of admission and a second sampling was done from the available individuals (38 dengue and 13 OFI cases) at the time of defervescence. Total RNA was extracted from the Peripheral blood mononuclear cells and the transcripts level of Nox-2 and Nrf2 were analysed by qPCR. On DOA, both Nox-2 and Nrf2 expression was found to be down regulated in dengue and OFI cases (P < 0.05) compared to healthy controls. Interestingly at defervescence, the transcript levels were found to be significantly increased in dengue cases unlike OFI, where no such increment was evidenced. From DOA to DOD, the study observed a signficant increase in the levels of Nox-2 transcripts (P < 0.05) both in SD and NSD cases. But a significant Nrf2 activation was not observed in SD cases as we found in NSD cases. Thus  a steady and significant increase in Nox-2 transcript level in severe, non-severe and secondary dengue infected groups observed in the current study supports the earlier reports on the involvement of anti-oxidant response in dengue severity. However further studies on its protein levels and mechanistic action would decipher the exact role of these potential molecules in the disease virulence.

A Study on Gene Expression Profile of Endogenous Antioxidant Enzymes: CAT, MnSOD and GPx in Dengue Patients

Dengue is an arthropod-borne threat among tropical countries. Currently no effective means to treat the virus or to predict which patient will develop the severe form of the disease. Recently the relationship between oxidative/antioxidative response and dengue pathogenesis was suggested. Based on this the present study has analysed the expression of endogenous antioxidant genes: Catalase (CAT), Superoxide dismutase (MnSOD) and Glutathione peroxidase in patients with dengue compared to other febrile illness (OFI) and healthy controls. The study enrolled 88 dengue confirmed patients comprising 56 were patients with non-severe dengue, and 32 were severe dengue cases, 31 were patients with OFI, and 63 healthy controls were also involved. Peripheral blood mononuclear cells isolated from patients and controls during the day of admission and from the available cases on the day of defervescence were used to estimate the transcript levels by quantitative PCR. The expression levels of all the three genes were found to be down-regulated throughout the course of dengue infection (p < 0.05) and OFI cases compared to healthy controls. Within dengue group, no significant difference was observed in any of the parameters between severe and non-severe cases. Interestingly, a significant down-regulation of MnSOD expression was recorded in secondary dengue infection compared to primary during admission (p < 0.05). It was found that all the down-regulated study genes have positively correlated in all dengue cases during the day of admission (p < 0.01). But during defervescence, the same was found only between CAT and MnSOD. Down-regulated endogenous antioxidant enzymes during dengue infection could be the possible rationale of oxidative stress reported in dengue disease earlier. The present study markers could not distinguish dengue from OFI cases and severe from non-severe dengue cases. Mechanism of down-regulation has to be explored further which will pave the way for the therapeutic target in dengue disease.

Use of Warning Signs for Dengue by Pediatric Health Care Staff in Brazil

OBJECTIVE

The aim of this study was to describe the use of dengue warning signs by pediatric healthcare staff in the Brazilian public health care system.

METHODS

Cross-sectional study (2012) with physicians, nurses, and nurse technicians assisting children in five health care facilities. Participants reported the use and importance of dengue warning signs in pediatrics clinical practice through a structured questionnaire. Differences in the use of signs (chi-square test) and in the ranking assigned to each of them (Kruskal-Wallis) were assessed according to health care occupation and level of care (p<0.05).

RESULTS

The final sample comprised 474 participants (97%), mean age of 37 years (standard deviation = 10.3), mainly females (83.8%), physicians (40.1%) and from tertiary care (75.1%). The majority (91%) reported using warning signs for dengue in pediatrics clinical practice. The most widely used and highly valued signs were major hemorrhages (gastrointestinal, urinary), abdominal pain, and increase in hematocrit concurrent or not with rapid decrease in platelet count. Persistent vomiting as well as other signs of plasma leakage such as respiratory distress and lethargy/restlessness were not identified as having the same degree of importance, especially by nurse technicians and in primary or secondary care.

DISCUSSION

Although most health care staff reported using dengue warning signs, it would be useful to extend the training for identifying easily recognizable signs of plasma leakage that occur regardless of bleeding.

Clinical and laboratory signs associated to serious dengue disease in hospitalized children

OBJECTIVE

To evaluate the validity of clinical and laboratory signs to serious dengue disease in hospitalized children.

METHODS

Retrospective cohort of children (<18 years) hospitalized with dengue diagnosis (2007-2008). Serious dengue disease was defined as death or use of advanced life support therapy. Accuracy measures and area under the receiver operating characteristic curve were calculated.

RESULTS

Of the total (n=145), 53.1% were female, 69% aged 2-11 years, and 15.9% evolved to the worse outcome. Lethargy had the best accuracy (positive likelihood ratio >19 and negative likelihood ratio <0.6). Pleural effusion and abdominal distension had higher sensitivity (82.6%). History of bleeding (epistaxis, gingival or gastrointestinal bleeding) and severe hemorrhage (pulmonary or gastrointestinal bleeding) in physical examination were more frequent in serious dengue disease (p<0.01), but with poor accuracy (positive likelihood ratio=1.89 and 3.89; negative likelihood ratio=0.53 and 0.60, respectively). Serum albumin was lower in serious dengue forms (p<0.01). Despite statistical significance (p<0.05), both groups presented thrombocytopenia. Platelets count, hematocrit, and hemoglobin parameters had area under the curve <0.5.

CONCLUSIONS

Lethargy, abdominal distension, pleural effusion, and hypoalbuminemia were the best clinical and laboratorial markers of serious dengue disease in hospitalized children, while bleeding, severe hemorrhage, hemoconcentration and thrombocytopenia did not reach adequate diagnostic accuracy. In pediatric referral hospitals, the absence of hemoconcentration does not imply absence of plasma leakage, particularly in children with previous fluid replacement. These findings may contribute to the clinical management of dengue in children at referral hospitals.

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.

Development of dengue infection severity score

Objectives. To develop a simple scoring system to predict dengue infection severity based on patient characteristics and routine clinical profiles. Methods. Retrospective data of children with dengue infection from 3 general hospitals in Thailand were reviewed. Dengue infection was categorized into 3 severity levels: dengue infection (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Coefficients of significant predictors of disease severity under ordinal regression analysis were transformed into item scores. Total scores were used to classify patients into 3 severity levels. Results. Significant clinical predictors of dengue infection severity were age >6 years, hepatomegaly, hematocrit ≥40%, systolic pressure <90 mmHg, white cell count >5000 / μ L, and platelet ≤50000 / μ L. The derived total scores, which ranged from 0 to 18, classified patients into 3 severity levels: DF (scores <2.5, n = 451, 58.1%), DHF (scores 2.5-11.5, n = 276, 35.5%), and DSS (scores >11.5, n = 50, 6.4%). The derived score correctly classified patients into their original severity levels in 60.7%. An under-estimation of 25.7% and an over-estimation of 13.5% were clinically acceptable. Conclusions. The derived dengue infection severity score classified patients into DF, DHF, or DSS, correctly into their original severity levels. Validation of the score should be reconfirmed before application of routine practice.

[Death from dengue fever as a sentinel event for evaluation of quality of healthcare: a case study in two municipalities in Northeast Brazil, 2008]

Despite the existing resources for adequate dengue patient care in the Brazilian healthcare system, the case-fatality rate for the disease is still high in the country. In order to identify factors associated with dengue-related death, this study evaluated quality of care according to the degree of implementation of specific measures, the technical and scientific quality of care, and access to health services in two municipalities (counties) in Northeast Brazil. An evaluative study of the implementation analysis type was performed, with death from dengue as the sentinel event for quality of care. To assess the degree of implementation and quality of care, the study scored the interview criteria and patient chart analysis; access was evaluated by thematic analysis. As for structure and process, the health services were found to be partially adequate (70%). No geographic or economic barriers were found to explain the occurrence of deaths. Technical and scientific quality failed to achieve adequate levels in the municipalities (46% and 30%) or in the specific services, and clinical management of dengue by the health services proved insufficient.

The importance of accurate diagnosis of dengue fever

Dengue infection is the name of an important arboviral infection that is common in tropical countries. This infection can cause acute febrile illness with possible important serious consequences, hemorrhage and shock. In its most severe subtype – dengue hemorrhagic fever – the fatality rate is very high. In a case of dengue infection, for management to succeed, early diagnosis and prompt treatment is very important. There are many possible investigations with which to diagnose dengue. However, limitations can still be discerned for each method, but the most important consideration is the correctness of the diagnosis. Similar to any kind of laboratory diagnosis, error can be expected in laboratory diagnosis for dengue, and this is an important topic to be considered. In this article, the diagnosis of dengue will be discussed, with special focus on problems to be kept in mind to avoid errors.