Predictors and Clinical Outcomes of Poor Platelet Recovery in Adult Dengue With Thrombocytopenia: A Multicenter, Prospective Study

A Critical Analysis of Intracranial Hemorrhage as a Fatal Complication of Dengue Fever

Dengue fever is the most rapidly spreading mosquito-borne virus in the world, infecting about 100 million individuals. A rare but possibly dangerous consequence of dengue illness is intracranial hemorrhage (ICH). Currently, the pathogenesis of ICH is unknown. A number of studies have found a variety of risk factors for ICH in dengue. In addition, studies have reported the use of emergency surgery while monitoring thrombocytopenia in the therapy of dengue ICH. This review enumerates the potential predictors of ICH in dengue, discusses the use of brain imaging, and mentions the possibility of emergency surgery.

Secondary dengue serotype 1 infection causing dengue shock syndrome with rhombencephalitis and bleeding associated with refractory thrombocytopenia: A case report

Background

Dengue has a wide spectrum of manifestations, from an asymptomatic condition to dengue shock syndrome. Extensive plasma leakage, severe bleeding, or both, could lead to dengue shock syndrome, a common cause of death in dengue-infected patients. Thrombocytopenia is a common laboratory finding in dengue, which correlates with the disease severity and rapidly resolves during the recovery phase. Therefore, refractory thrombocytopenia is rare in patients with dengue. Rhombencephalitis is an inflammatory disease affecting the hindbrain, rarely associated with dengue. We report the second case of dengue-associated rhombencephalitis, wherein the patient developed dengue shock syndrome and severe bleeding associated with refractory thrombocytopenia.

Case report

A 47-year-old Thai female with secondary dengue serotype 1 infection developed dengue shock syndrome with rhombencephalitis, manifested as altered sensorium and status epilepticus in the critical phase. Cerebrospinal fluid analysis showed pleocytosis with predominantly mononuclear cells and high protein levels. Magnetic resonance imaging of the brain showed multifocal brain signal abnormalities involving the medulla oblongata, pons, midbrain, bilateral hippocampi, thalami, posterior limb of internal capsules, external capsules, and deep hemispheric white matter. The patient had partial neurological recovery following rhombencephalitis for one month. During the recovery phase, severe bleeding with refractory thrombocytopenia and acute kidney injury were observed. Methylprednisolone with eltrombopag was administered, which resulted in an increased the platelet count, cessation of bleeding and recovery of kidney function within 4 days.

Conclusions

Dengue is a potential cause of rhombencephalitis. Dengue-associated rhombencephalitis develops during the critical phase, with only partial neurological recovery. However, severe bleeding and refractory thrombocytopenia were also observed during the recovery phase. Methylprednisolone with a thrombopoietin receptor agonist could be an effective treatment for increasing platelet count and stopping bleeding in dengue.

Mimicking platelet indices in patients with malaria and dengue hemorrhagic fever: characteristics and clinical applications

Background

Although platelet indices are routinely available using automated blood cell counters, the clinical applications of these parameters for malaria and dengue hemorrhagic fever (DHF) have not been substantially implemented. We conducted this study to investigate the potential role of platelet indices as a prognostic marker in adult patients with Plasmodium vivax malaria, Plasmodium falciparum malaria, and DHF admitted to the Hospital for Tropical Diseases, Bangkok, Thailand.

Methods

We enrolled 219 eligible patients, comprising 96 with P. falciparum malaria, 71 with P. vivax malaria, and 52 with DHF. We evaluated the study groups’ baseline clinical features and alterations of platelet indices during the first 4 days of admission.

Results

Upon admission, the initial laboratory findings showed no statistically significant difference in platelet count (PC), plateletcrit (PCT), or platelet distribution width (PDW) between patients with P. vivax and P. falciparum; however, mean platelet volume (MPV) was significantly higher in patients with P. falciparum. Comparisons of the initial platelet indices in malaria and DHF showed that only PC and PCT were significantly lower in DHF. Although MPV in DHF tended to be lower than in malaria, a statistically significant difference was observed only with P. falciparum. Moreover, the results also showed no significant alterations in the platelet indices among the study groups during the first 4 days of admission.

Conclusions and recommendations

Clinical presentations of DHF and malaria are nonspecific and may overlap with other common tropical diseases. Alterations of initial platelet indices may be investigated in P. vivax and P. falciparum malaria mimicking DHF. Although a significant reduction in PC and PCT in DHF might be a clue for differential diagnosis of malaria, the use of MPV and PDW might be impractical. We suggest that appropriate laboratory diagnoses for malaria and dengue infections are still needed for the differential diagnosis of acute febrile patients who have a risk of malaria or dengue infections. To clarify the clinical utility of platelet indices in patients with dengue and malaria, further studies are required that particularly include patients with different severities, geographical areas, and levels of health care settings.

Dengue vaccine development: challenges and prospects

PURPOSE OF REVIEW

Dengue vaccine development is a high public health priority. To date, no dengue vaccine is in widespread use. Here we review the challenges in dengue development and the latest results for the second-generation dengue vaccines.

RECENT FINDINGS

The biggest hurdle is the immunological interaction between the four antigenically distinct dengue serotypes. The advantages of second-generation dengue vaccines are the inclusion of nonstructural proteins of the dengue backbone and a more convenient dosing with reduced numbers of doses needed.

SUMMARY

Although dengue-primed individuals can already benefit from vaccination with the first licensed dengue vaccine CYD-TDV, the public health need for the dengue-naive population has not yet been met. The urgent need remains to identify correlates of both protection and enhancement; until such correlates have been identified, all second-generation dengue vaccines still need to go through full phase 3 trials. The 5-year efficacy and safety data for both second-generation dengue vaccines are imminent.

Factors associated with thrombocytopenia in patients with dengue fever: a retrospective cohort study

OBJECTIVE

Some patients with dengue fever tend to develop thrombocytopenia during the course of infection and are thus vulnerable to haemorrhagic manifestations and other complications. However, the factors associated with the development of thrombocytopenia are unknown. We aimed to identify factors associated with an increased risk of thrombocytopenia and haematological changes in patients with confirmed dengue fever.

DESIGN

Retrospective cohort study.

SETTING

Brazilian multicentre primary care databases.

PARTICIPANTS

387 patients had positive laboratory serological confirmation of dengue infection during 2014. The data were identified from two databases: Notification of Injury Information System (SINAN) and Municipal Laboratory.

MAIN OUTCOME MEASURE

The presence of thrombocytopenia (platelet count <1 50×10⁹/L). The associations of factors that predisposed patients to thrombocytopenia and haematological changes were analysed using logistic regression. ORs and 95% CIs were calculated.

RESULTS

Among 387 patients, 156 had both dengue and thrombocytopenia. The risk factors associated with thrombocytopenia included male sex (OR: 1.77, 95% CI: 1.16 to 2.71, p=0.007), age of 46-64 years (OR: 2.20, 95% CI: 1.15 to 4.21, p=0.009) or ≥65 years (OR: 3.02, 95% CI: 1.40 to 6.50, p=0.002), presence of leucopenia (OR: 6.85, 95% CI: 4.27 to 10.99, p<0.001) and high mean corpuscular haemoglobin (MCH) levels (OR: 2.00, 95% CI: 1.29 to 3.12, p=0.005).

CONCLUSION

Older age, male sex, presence of leucopenia and high MCH levels were identified as risk factors associated with the development of thrombocytopenia in this population.