Prospective observational study of low thresholds for platelet transfusion in adult dengue patients

Endemic or regionally limited bacterial and viral infections in haematopoietic stem-cell transplantation recipients: a Worldwide Network for Blood and Marrow Transplantation (WBMT) Review

Literature discussing endemic and regionally limited infections in recipients of haematopoietic stem-cell transplantation (HSCT) outside western Europe and North America is scarce. This Worldwide Network for Blood and Marrow Transplantation (WBMT) article is part one of two papers aiming to provide guidance to transplantation centres around the globe regarding infection prevention and treatment, and considerations for transplantation based on current evidence and expert opinion. These recommendations were initially formulated by a core writing team from the WBMT and subsequently underwent multiple revisions by infectious disease experts and HSCT experts. In this paper, we summarise the data and provide recommendations on several endemic and regionally limited viral and bacterial infections, many of which are listed by WHO as neglected tropical diseases, including Dengue, Zika, yellow fever, chikungunya, rabies, brucellosis, melioidosis, and leptospirosis.

Dengue Virus and Platelets: From the Biology to the Clinic

Dengue is one of the most important vector-borne viral illnesses found in tropical and subtropical regions. Colombia has one of the highest rates of dengue cases in the Americas. Severe dengue virus (DENV) infection presents with capillary leakage, hemorrhage, and organ compromise, eventually leading to death. Over the years, there have been many efforts to develop a vaccine that guarantees protective immunity, but they have been partially successful, as such immunity would need to guarantee protection against four distinct viral serotypes. Absolute platelet count is a laboratory parameter used to monitor the clinical progression of DENV, as infection is often accompanied by thrombocytopenia. Although this finding is well described with respect to the natural history of the disease, there are various hypotheses as to the cause of this rapid decrease, and several in vivo and ex vivo models have been used to explain the effect of DENV infection on platelets and their precursors. DENV infects and activates platelets, facilitating their elimination through recognition by phagocytic cells and peripheral margination. However, infection also affects the precursors in the bone marrow by modulating megakaryopoiesis. The objective of this article is to explore various proposed mechanisms of DENV-induced thrombocytopenia to better understand the pathophysiology and clinical presentations of this highly relevant viral infection.

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.

Other Potentially Life-Threatening Conditions with Mucocutaneous Findings (Leptospirosis, Typhoid Fever, Dengue, Diphtheria, Murine Typhus)

There are several conditions with mucocutaneous findings that are potentially life-threatening, particularly in certain vulnerable populations. In this chapter, leptospirosis, typhoid fever, dengue, diphtheria, and murine typhus are reviewed. The disease time course of classic and atypical presentations is detailed to assist making the diagnosis in subtle cases. Associated symptoms are discussed as well as a comparison with disease mimics and differential diagnoses. Key diagnostic features are emphasized, and evidence-based management of each condition is detailed in this chapter.

Potential Harm of Prophylactic Platelet Transfusion in Adult Dengue Patients

Background

Thrombocytopenia is a hallmark of dengue infection, and bleeding is a dreaded complication of dengue fever. Prophylactic platelet transfusion has been used to prevent bleeding in the management of dengue fever, although the evidence for its benefit is lacking. In adult dengue patients with platelet count <20,000/mm³ without bleeding, we aimed to assess if prophylactic platelet transfusion was effective in reducing clinical bleeding and other outcomes.

Method

We conducted a retrospective non-randomised observational study of dengue patients with platelet count < 20,000/mm³ without bleeding (except petechiae) admitted to Tan Tock Seng Hospital from January 2005 to December 2008. Baseline characteristics and clinical outcomes were compared between the non-transfused vs. transfused groups. Outcomes studied were clinical bleeding, platelet increment, hospital length of stay, intensive care unit admission and death.

Results

Of the 788 patients included, 486 received prophylactic platelet transfusion. There was no significant difference in the presence of clinical bleeding in the two groups (18.2% in non-transfused group vs. 23.5% in transfused group; P = 0.08). Patients in the transfused group took a median of 1 day longer than the non-transfused group to increase their platelet count to 50,000/mm³ or more (3 days vs. 2 days, P <0.0001). The median duration of hospital stay in the non-transfused group was 5 days vs. 6 days in the transfused group (P< 0.0001). There was no significant difference in the proportion requiring ICU admission (non-transfused 0.66% vs. transfused 1.23%, P = 0.44) and death (non-transfused 0% vs. transfused 0.2%, P = 0.43).

Conclusion

Platelet transfusion in absence of bleeding in adult dengue with platelet count <20,000/mm³ did not reduce bleeding or expedite platelet recovery. There was potential harm by slowing recovery of platelet count to >50,000/mm³ and increasing length of hospitalization.

Thrombocytopenia is one of the most prominent clinical features in dengue infection. This may manifest clinically as bleeding, which carries significant morbidity and mortality. For many years, clinicians have given dengue patients platelet transfusion in a bid to increase their platelet counts to prevent hemorrhagic manifestations. However, this practice has not been proven to reduce the risk of bleeding in dengue. Conversely, transfusion of blood products may be detrimental to patients as it can carry risks of fluid overload, transmission of infectious diseases and transfusion reactions. In this study, the authors found that platelet transfusion in the absence of bleeding in adult dengue patients did not prevent bleeding. Instead, this practice is associated with a slower platelet recovery and increased length of hospitalisation. These findings may contribute to better clinical management of thrombocytopenia in dengue patients and limit the use of these precious blood products.

Physician survey to determine how dengue is diagnosed, treated and reported in puerto rico

Dengue is a major cause of morbidity in Puerto Rico and is well-known to its physicians. Early case identification and timely initiation of treatment for patients with severe dengue can reduce medical complications and mortality. To determine clinical management and reporting practices, and assess knowledge of dengue and its management, a survey was sent to 2,512 physicians with a medical license in Puerto Rico. Of the 2,313 physicians who received the survey, 817 (35%) completed the questionnaire. Of the respondents, 708 were currently practicing medicine; 138 were board certified (Group 1), 282 were board eligible (Group 2), and 288 had not finished residency (Group 3). Although respondents clinically diagnosed, on average, 12 cases of dengue in the preceding three months, 31% did not report any suspected cases to public health officials while about half (56%) reported all cases. Overall, 29% of respondents correctly identified early signs of shock and 48% identified severe abdominal pain and persistent vomiting as warning signs for severe dengue with the proportion of correct respondents highest in Group 1. Reportedly about sixty percent (57%) appropriately never give corticosteroids or prophylactic platelet transfusions to dengue patients. One third (30%) of respondents correctly identified administration of intravenous colloid solution as the best treatment option for dengue patients with refractory shock and elevated hematocrit after an initial trial of intravenous crystalloids, and nearly one half (46%) correctly identified administration of a blood transfusion as the best option for dengue patients with refractory shock and decreased hematocrit after a trial of intravenous crystalloids. Even though dengue has been endemic in Puerto Rico for nearly 4 decades, knowledge of dengue management is still limited, compliance with WHO treatment guidelines is suboptimal, and underreporting is significant. These findings were used to design a post graduate training course to improve the clinical management of dengue.

Dengue is a major cause of morbidity in Puerto Rico and is well-known to its physicians. Early case identification and timely initiation of treatment for patients with severe dengue can reduce medical complications and mortality. We conducted a survey among physicians who practice in Puerto Rico to determine clinical management and reporting practices and assess knowledge of dengue and its management. We found that although respondents clinically diagnosed, on average, 12 cases of dengue in the preceding three months, one third did not report any suspected cases to public health officials while about half reported all cases. We found that knowledge of dengue management was limited and compliance with WHO treatment guidelines was not optimal. As other dengue endemic countries have reported similar findings, a sustained continuing medical education training initiative may be necessary to improve case detection and clinical management even in countries where the disease is common. Our findings were used to design a postgraduate training course to improve the clinical management of dengue.

Direct costs of dengue hospitalization in Brazil: public and private health care systems and use of WHO guidelines

BACKGROUND

Dengue, an arboviral disease, is a public health problem in tropical and subtropical regions worldwide. In Brazil, epidemics have become increasingly important, with increases in the number of hospitalizations and the costs associated with the disease. This study aimed to describe the direct costs of hospitalized dengue cases, the financial impact of admissions and the use of blood products where current protocols for disease management were not followed.

METHODS AND RESULTS

To analyze the direct costs of dengue illness and platelet transfusion in Brazil based on the World Health Organization (WHO) guidelines, we conducted a retrospective cross-sectional census study on hospitalized dengue patients in the public and private Brazilian health systems in Dourados City, Mato Grosso do Sul State, Brazil. The analysis involved cases that occurred from January through December during the 2010 outbreak. In total, we examined 8,226 mandatorily reported suspected dengue cases involving 507 hospitalized patients. The final sample comprised 288 laboratory-confirmed dengue patients, who accounted for 56.8% of all hospitalized cases. The overall cost of the hospitalized dengue cases was US $210,084.30, in 2010, which corresponded to 2.5% of the gross domestic product per capita in Dourados that year. In 35.2% of cases, blood products were used in patients who did not meet the blood transfusion criteria. The overall median hospitalization cost was higher (p = 0.002) in the group that received blood products (US $1,622.40) compared with the group that did not receive blood products (US $550.20).

CONCLUSION

The comparative costs between the public and the private health systems show that both the hospitalization of and platelet transfusion in patients who do not meet the WHO and Brazilian dengue guidelines increase the direct costs, but not the quality, of health care.

Dengue therapeutics, chemoprophylaxis, and allied tools: state of the art and future directions

Dengue is the most common arboviral disease of humans. There is an unmet need for a therapeutic intervention that reduces the duration and severity of dengue symptoms and diminishes the likelihood of severe complications. To this end, there are active discovery efforts in industry and academia to develop interventions, with a focus on small molecule inhibitors of dengue virus replication that are suitable for therapy or chemoprophylaxis. Advancements in animal models of dengue virus infection together with the possibility of a dengue human infection model have further enhanced the platform for dengue drug discovery. Whilst drug discovery efforts gestate, there are ongoing clinical research designed to benefit today's patients, including trials of supportive care interventions, and descriptive studies that should improve the ability of clinicians to make an accurate diagnosis early in the illness course and to identify patients most at risk of progression to severe disease. This review provides a state of the art summary of dengue drug discovery, clinical trials, and supportive allied research and reflects discussions at the 2nd International Dengue Therapeutics Workshop held in Ho Chi Minh City, Vietnam, in December 2013.

Clinical and laboratory characteristics of patients with dengue hemorrhagic fever manifestations and their transfusion profile

Background

Dengue is an infectious disease with a recurring incidence, especially in developing countries. Despite recent economic growth, success in disease control has not been achieved, and dengue has evolved from cyclic epidemic outbreaks to a lack of seasonality. The lack of scientific basis for the proper management of cases with hemorrhagic manifestations, especially regarding transfusion procedures, might contribute to the high death rate in potentially avoidable cases.

Objective

The aim of the study was to identify the clinical and laboratory manifestations in hemorrhagic dengue fever treated at the emergency services in Rio Branco, AC, Brazil, as well as to describe transfusion characteristics of patients and identify possible prognostic factors.

Methods

A retrospective descriptive study was performed to analyze the distribution of relative frequencies of clinical and laboratory variables. The study was carried out in Rio Branco with confirmed dengue fever cases. Secondary data were obtained by Acre Epidemiological Surveillance teams of cases with bleeding or platelet counts under 100.0 × 10⁹/L. The patients' clinical, laboratory and transfusion data were obtained from hospital records.

Results

A total of 90,553 dengue cases were reported of which 7,447 had serologic confirmation; 267 cases had hemorrhagic manifestations and 193 patients were located. Nearly half of the patients had anemia and the mean of the lowest platelet count of these patients was 26.4 × 10⁹/L. Platelet concentrate was transfused in 22.3% of cases with a mean of 7.5 IU/patient, fresh frozen plasma in 21.2% with a mean of 5.2 IU/patient and just 2.6% of patients received concentrated red blood cells with a mean of 3.2 IU/patient. Bleeding led to transfusions. Signs of plasma leakage and cardiopulmonary dysfunction were correlated to unfavorable outcomes.

Conclusion

The pattern of clinical and laboratory criteria observed in this investigation does not differ from the literature. Transfusions were used as part of the treatment of dengue hemorrhagic fever manifestations. Some of the clinical manifestations may be related to unfavorable outcomes.

© 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. All rights reserved.

Prophyactic platelet transfusion in stable dengue Fever patients: is it really necessary?

Our hospital is a referral centre for Jehovah's Witnesses (JW) patients, who as a matter of religious belief refuse transfusions of blood/blood components. We have treated JW patients with dengue fever (DF) and thrombocytopenia without platelet transfusion, without any mortality or major morbidities. We retrospectively compared the duration needed for platelet recovery and duration of hospitalization of DF with thrombocytopenia in those treated with prophylactic platelet transfusion and JW patients who were managed without these. Among JW patients, platelet counts recovered to >50,000 in 2.57 days (Mean) as compared to those who received prophylactic platelet transfusion, who recovered in 4.43 days (P value < 0.0001). They also had significantly less number of days of hospitalization (3.68 days vs 5.13 days, P value < 0.0001). These differences persisted even when a subgroup analysis of patients who had nadir platelet count less than 10,000 were done. Most importantly, none of the patients in either group suffered any significant morbidity or mortality. Prophylactic platelet transfusion in clinically stable DF patients was associated with significant delay in platelet recovery and increased duration of hospitalization, even though was not harmful in terms of morbidity or mortality. Though number of subjects involved in the study was small, this brief report further adds to the current evidence that prophylactic platelet transfusion in clinically stable DF patients with a platelet count more than 10,000/cmm is not indicated.

Clinical profile of concurrent dengue fever and Plasmodium vivax malaria in the Brazilian Amazon: case series of 11 hospitalized patients

Malaria and dengue fever are the most prevalent vector-borne diseases worldwide. This study aims to describe the clinical profile of patients with molecular diagnosis of concurrent malaria and dengue fever in a tropical-endemic area. Eleven patients with concurrent dengue virus (DENV) and Plasmodium vivax infection are reported. Similar frequencies of DENV-2, DENV-3, and DENV-4 were found, including DENV-3/DENV-4 co-infection. In eight patients, the World Health Organization (WHO) criteria for severe malaria could be fulfilled (jaundice being the most common). Only one patient met severe dengue criteria, but warning signs were present in 10. Syndromic surveillance systems must be ready to identify this condition to avoid misinterpretation of severity attributed to a single disease.

Clinical features of dengue in a large Vietnamese cohort: intrinsically lower platelet counts and greater risk for bleeding in adults than children

BACKGROUND

As dengue spreads to new geographical regions and the force of infection changes in existing endemic areas, a greater breadth of clinical presentations is being recognised. Clinical experience suggests that adults manifest a pattern of complications different from those observed in children, but few reports have described the age-related spectrum of disease in contemporaneous groups of patients recruited at the same geographical location.

METHODOLOGY/PRINCIPAL FINDINGS

Using detailed prospectively collected information from ongoing studies that encompass the full spectrum of hospitalised dengue cases admitted to a single hospital in southern Vietnam, we compared clinical and laboratory features, management, and outcome for 647 adults and 881 children with confirmed dengue. Signs of vascular leakage and shock were more frequent and more severe in children than adults, while bleeding manifestations and organ involvement were more common in adults. Additionally, adults experienced significantly more severe thrombocytopenia. Secondary infection but not serotype was independently associated with greater thrombocytopenia, although with a smaller effect than age-group. The effect of age-group on platelet count was also apparent in the values obtained several weeks after recovery, indicating that healthy adults have intrinsically lower counts compared to children.

CONCLUSIONS/SIGNIFICANCE

There are clear distinctions between adults and children in the pattern of complications seen in association with dengue infection, and these depend partly on intrinsic age-dependent physiological differences. Knowledge of such differences is important to inform research on disease pathogenesis, as well as to encourage development of management guidelines that are appropriate to the age-groups at risk.

Clinical presentation of dengue among patients admitted to the adult emergency department of a tertiary care hospital in Martinique: implications for triage, management, and reporting

STUDY OBJECTIVE

During dengue epidemics, emergency physicians face large numbers of patients with acute febrile illness. Triage algorithms and appropriate reporting systems are useful to manage patients and prioritize resources. We identify possible adaptations to these systems to improve the management of patients during epidemics.

METHODS

In a prospective observational study in the adult emergency department (ED) of a tertiary care hospital, we enrolled all patients with febrile illness and a confirmed diagnosis of dengue (ribonucleic acid identification). We then retrospectively classified cases according to the initial clinical presentation at the ED.

RESULTS

We enrolled 715 patients (332 male patients), aged 14 to 91 years (median 35 years). Severe illness was documented in 332 cases (46.4%) and was mostly caused by serotype 2, or a secondary infection of any serotype. Severe forms included dengue hemorrhagic fever or dengue shock syndrome (104/332; 31.3%), severe bleeding (9/332; 2.7%), and acute organ failure (56/332; 16.9%). The other patients with severe illness (171/332; 51.5%) presented with symptoms of presyncope, intense weakness, prolonged gastrointestinal symptoms, and hypotension. This presentation was common during epidemics and appeared to be associated with dehydration and electrolyte loss that improved markedly within 24 hours with saline solution infusion. This group did not have evidence of plasma leakage, although similar features were observed in patients with dengue hemorrhagic fever/dengue shock syndrome.

CONCLUSION

Dengue has a wide range of clinical presentations in the ED. Many patients who appear seriously ill on presentation will respond to intravenous fluids.

The pathogenesis of dengue

Dengue is an important cause of childhood and adult morbidity in Asian and Latin American countries and its geographic footprint is growing. The clinical manifestations of dengue are the expression of a constellation of host and viral factors, some acquired, others intrinsic to the individual. The virulence of the virus plus the flavivirus infection history, age, gender and genotype of the host all appear to help shape the severity of infection. Similarly, the characteristics of the innate and acquired host immune response subsequent to infection are also likely determinants of outcome. This review summarises recent developments in the understanding of dengue pathogenesis and their relevance to dengue vaccine development.