New thinking in dengue case classification : why change
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Date
2011-01-25
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Journal of the Vector - Borne Diseases
Abstract
The DENCO, multi-countries study group had suggested new dengue classification to replace the current WHO dengue classification. The new classification simply divides patients into 2 categories; dengue (with/without warning signs) and severe dengue. They claimed that it is simple, friendly used and that the sensitivity and specificity to detect severe dengue cases is 95%. But when we look carefully we found that this new dengue classification is too non-specific, making over-diagnosis and need laboratory to confirm for dengue infections (except those with criteria of evidence of plasma leakage). This suggested new classification has no advantages over WHO criteria because it does not address the important hallmark of dengue hemorrhagic fever (DHF), i.e. plasma leakage as in WHO case definition which contributed to the high specificity of WHO criteria for DHF. Current WHO classification (Dengue Fever, DHF and Dengue shock syndrome) has sensitivity of 62% and specificity of 92%. Some modification of current WHO classification by adding another category of unusual manifestations of dengue (or expanded dengue syndrome) in order to cover those severe/complicated dengue cases with multiple organs involvement is recommended. In addition, WHO case definition criteria are also proposed for modification in order to increase the sensitivity more as follows: Two major criteria (Fever and plasmaleakage) and one minor criterion (Tourniquet test positive or petechiae or thrombocytopenia) are required for the diagnosis of DHF/ DSS. To increase the sensitivity more, plasma leakage can be re-defined as hemoconcentration 15-20% in those who received IV fluid and thrombocytopenia can be re-defined as Platelet count \< 150,000 cells/cumm.
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Journal of the Vector - Borne Diseases; Vol. 6 No. 1 January - June 2009; 23-34