Evaluation of the WHO revised criteria for classification of clinical disease severity in acute adult dengue infection

Sd Jayaratne,Thashi Chang,Graham S Ogg,Sachie Fernando,Vajini Atukorale,Gathsaurie Neelika Malavige,Tharindu Wijesinghe,Laksiri Gomes

doi:10.1186/1756-0500-5-645

Abstract

BackgroundThe WHO guidelines were revised recently to identify patients with severe dengue (SD) early. We proceeded to determine the usefulness of the warning signs in the new WHO guidelines in predicting SD and we have also attempted to define other simple laboratory parameters that could be useful in predicting SD.MethodsClinical and laboratory parameters were recorded in 184 patients in 2011, with confirmed dengue viral infections, admitted to a medical ward in two tertiary care hospitals in Colombo, Sri Lanka.ResultsWe found that the presence of 5 or more dengue warning signs were significantly (p = 0.02) associated with the development of SD (odds ratio 5.14, 95% CI = 1.312 to 20.16). The AST levels were significantly higher (p = 0.0001) in patients with abdominal pain (mean 243.5, SD ± 200.7), when compared to those who did not have abdominal pain (mean 148.5, SD ± 218.6). Lymphocyte counts <1,500 cells/mm3 were significantly (p = 0.005) associated with SD (odds ratio 3.367, 95% CI 1.396 to 8.123). High AST levels were also significantly associated (p < 0.0001) with SD (odds ratio 27.26, 95% CI 1.632 to 455.2). Platelet counts <20,000cells/mm3, were again significantly associated (p < 0.001) with severe disease (odds ratio 1.632 to 455.2, 95% CI 3.089 to 14.71). The PCR was positive in 26/84 of the patients and we found that the infecting serotype was DEN-1 in all 26 patients.ConclusionsThe presence of 5 or more warning signs appears to be a predictor of SD. Lymphocyte counts <1,500 cells/mm3, platelet counts <20,000/mm3 and raised AST levels were associated with SD and could be used to help identify patients who are likely to develop SD.

Highlights

The WHO guidelines were revised recently to identify patients with severe dengue (SD) early
Based on the 1997 WHO classification all our patients would have been classified as having dengue haemorrhagic fever (DHF) because all of them had thrombocytopenia (100,000 cells/mm3 or less) and a rising HCT which was defined as a HCT increase of ≥20% from the baseline of patient or population of the same age [19]
In the 2011 WHO guidelines, fever accompanied by a haemorrhagic manifestation along with thrombocytopenia and haemoconcentration is considered as diagnostic as DHF [3]

Summary

Introduction

The WHO guidelines were revised recently to identify patients with severe dengue (SD) early. It is estimated that 2.1 million cases of dengue haemorrhagic fever (DHF)/dengue shock syndrome (DSS) occur every year resulting in 21,000 deaths [1]. Sri Lanka has been affected by epidemics of DHF for over 2 decades. Dengue viral infections have been endemic in Sri Lanka since the mid 1960s, which was when the first cases of DF/DHF were reported [4,5]. The Sri Lankan population had been exposed to the virus for decades, severe forms of dengue infection (DHF/DSS) were rare before 1989. Since the number of cases of dengue have been rising each year and in recent years dengue ranks highest in mortality in mosquito borne infection in Sri Lanka [6].

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