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Dengue Hemorrhagic Fever: The Sensitivity and Specificity of the WHO Definition for Identification of Severe Cases of Dengue in Thailand, 1994–2005 R2.

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Presentation on theme: "Dengue Hemorrhagic Fever: The Sensitivity and Specificity of the WHO Definition for Identification of Severe Cases of Dengue in Thailand, 1994–2005 R2."— Presentation transcript:

1 Dengue Hemorrhagic Fever: The Sensitivity and Specificity of the WHO Definition for Identification of Severe Cases of Dengue in Thailand, 1994–2005 R2 정상완 / Prof. 손준성 Anon Srikiatkhachorn, Robert V. Gibbons, Sharone Green, Daniel H. Libraty, Stephen J. Thomas, Timothy P. Endy, David W. Vaughn, a Ananda Nisalak, Francis A. Ennis, Alan L. Rothman Clinical Infectious Diseases 2010; 50:1135–1143

2 Background Classification of dengue illness published by the WHO in 1975 and updated in 1997 : undifferentiated febrile illness, dengue fever (DF), and Dengue hemorrhagic fever (DHF). DHF requires 4 diagnostic components: ▫ Fever, Hemorrhagic manifestation (skin bleeding, mucosal bleeding, GI bleeding, epistaxis, and menorrhagia) ▫ Thrombocytopenia ( PLT < 100,000 cells/mm3) ▫ Evidence of plasma leakage ( pleural effusion, ascites, hemoconcentration 20%, or hypoproteinemia) Dengue shock syndrome (DSS) : DHF with circulatory failure

3 Background The classification system : based upon clinical manifestations and laboratory values Several studies : a number of severe dengue cases have failed to meet the case definition of DHF WHO case definition of DHF ▫ identify “severe” dengue cases, as determined by the requirement for fluid replacement and blood transfusion.

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5 Participants and Procedures 1994–2005 Prospective study of children in Bangkok, Thailand 6 months and 15 years of age Suspected dengue virus infection with fever of < 3 days’ and without an obvious source of infection. Exclusion criteria ▫ Known chronic disease or signs of shock on presentation.

6 Participants and Procedures V/S, hemorrhagic manifestations, presence of leakage, tourniquet test results, CBC, albumin : collected daily. Dengue serologic testing : 5–9 days after discharge. treated in accordance with WHO guidelines. IV fluid was initiated when (1) signs suggestive of dehydration with poor oral intake (2) signs of poor peripheral perfusion (persistent tachycardia, delayed capillary refill, narrow pulse pressure<20mmHg) (3) a need for blood or colloid solution transfusion

7 Laboratory tests Virus : virus isolation in mosquitoes, a serotype-specific reverse-transcription PCR, ELISA Hematocrits : by finger stick, every 6 h during the first 18 h after defervescence. The percentage hematocrit change : (highest hematocrit during hospitalization hematocrit at convalescence)/hematocrit at convalescence

8 Clinical classification Other febrile illness (OFIs) : Patients without virologic or serologic evidence of dengue virus infection. Case classification 1) WHO case definitions : DF or DHF grade 1–4  reviewed by a physician expert who did not participate in patient care 2) Intervention requirements : dengue that required intervention (DRI) or dengue that did not require intervention (DNRI)  evaluate the association between case designation and disease severity. (1)use of IV fluid (2) receipt of fluid resuscitation (fluid equal to or exceeding a combine volume of maintenance fluid and 5% volume deficit on any day during the hospitalization) (3) transfusion

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10 Characteristics of Population

11 57% 15% 12% 125(30%)

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15 Discussion

16 Discussion Recent studies : questioned whether the WHO classification optimally identifies severe dengue cases. DHF, as defined by the WHO criteria, correlated strongly with the need for intervention. 15% of DF and 12% of OFI cases required intervention  heterogeneity in severity in each disease category.

17 Discussion A number of studies : a significant proportion of patients with dengue who experience shock did not fulfill the WHO DHF case definition 10 (76%) of 13 dengue cases with narrow pulse pressure were classified as DHF by the WHO case definitions. Lack of data on platelet counts, hematocrits, or lateral decubitus chest radiogram at critical time points.  disease severity irrespective of dengue case definitions.

18 Discussion WHO case definition demonstrated only 88% concordance rate with diagnoses assigned by a physician expert.  differences in the determination of hemoconcentration Plasma leakage and Thrombocytopenia ▫ important discriminating factors for both DHF and disease severity. ▫ Thrombocytopenia : also a marker of severity in patients with dengue who did not fulfill the WHO case definition of DHF.

19 Limitation not detect other severe manifestations (encephalitis,encephalopathy,myocarditis) The early recruitment and close observation ▫ resulted in fewer severe dengue cases need to be validated in other settings and in populations with different ethnicity.

20 Conclusion First, the current WHO criteria identify the majority (68%) patients with dengue who required intervention ▫ absence of serological or virological confirmation of dengue infection  a practical issue for resource-poor countries Second, plasma leakage and thrombocytopenia ▫ discriminate DHF from DF ▫ severe cases from milder cases


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