Admission ultrasonography as a predictive tool for thrombocytopenia and disease severity in dengue infection.

BACKGROUND: Ultrasound (US) is an investigation available in many acute care settings. Thrombocytopenia is a well-described complication of dengue infection and has been shown to correlate with disease severity. The purpose of this study was to assess the utility of admission ultrasonography in predicting thrombocytopenia and disease severity in patients infected with dengue virus. METHODS: Data were collected prospectively on 176 patients (male, n=86; female, n=90) admitted to the Nawaloka Hospital, Sri Lanka with dengue infection between December 2016 and August 2018. All patients had an US scan on admission and disease severity was determined using the World Health Organization 2009 classification. RESULTS: There were 106 (60.2%) cases of dengue with/without warning signs and 70 (39.8%) cases of severe dengue. Patients with an abnormal US on admission were more likely to have severe dengue. Gallbladder wall thickening was the most common US abnormality. Abnormal US findings significantly correlated with more pronounced thrombocytopenia from day 2 of admission. CONCLUSIONS: An abnormal US scan on admission can aid in identification of patients at risk of developing severe dengue and can be used as a novel clinical tool to identify patients at risk of severe thrombocytopenia.

Triple positivity for nonstructural antigen 1, immunoglobulin M and immunoglobulin G is predictive of severe thrombocytopaenia related to dengue infection.

BACKGROUND: The early identification of patients at risk of severe dengue infection (DI) is critical to guide clinical management. Non-structural antigen 1 (NS-1), immunoglobulin M (IgM) and immunoglobulin G (IgG) are used routinely for the diagnosis of DI. OBJECTIVES: We sought to evaluate whether positivity for NS-1, IgM and IgG individually or together is predictive of severe complications of DI. METHODS & MATERIALS: A prospective study was conducted among patients with DI admitted to our institution between 2014 and 2019. DI was diagnosed based on a positive NS1 or IgM. IgG was also tested on all the patients. Clinical data was obtained from electronic medical records at NH. Statistical analyses were performed using SPSS version 20. RESULTS: We collected data on 3504 patients. Patients who were positive for NS1, IgM and IgG (triple positive: TP) were more likely to develop severe DI (63.8 %) in comparison to those who were only NS1 positive (single positive: SP) (3.0 %) and patients with positive NS1 and IgM (double positive: DP) (7.5 %). [p = 0.001]. Regression analysis confirmed that TP status on admission was predictive of severe complications. (p < 0.01). Receiver operator characteristic curve (ROC) analysis showed (AUC: 84.8; sensitivity = 90.7 and specificity = 83.2) that TP status on admission is predictive of thrombocytopenia on day 5. The predictive power of TP status was superior to that of NS1 and IgG positivity. CONCLUSIONS: We propose that TP status on admission is a novel predictive factor for severe DI. Further studies are required to explore the biological basis for this finding.

The atypical lymphocyte count: a novel predictive factor for severe thrombocytopenia related to dengue.

BACKGROUND: Early identification of patients at risk of severe dengue disease (DD) is critical to guide its management. We evaluated whether the atypical lymphocyte count (ALC), generated from the Sysmex automated full blood count analyzer, is predictive of severe thrombocytopenia secondary to Dengue infection. METHODS: We prospectively collected data on patients admitted with DD between December 2017 and October 2018. ALC data were extracted from the Sysmex XS500i analyzer from day 1 to day 7 of admission. Clinical data were obtained from patients' medical records. RESULTS: We enrolled 256 patients with DD. A negative correlation between ALC on admission and platelet count on day 5 to day 7 (Spearmen's correlation; day 5:-0.485, day 6:-0.428 and day 7:-0.344) (p=0.001) was observed. Based on receiver operator characteristic curve analysis, we found that an ALC of >0.5x103/L had 90% sensitivity and 70% specificity for severe thrombocytopenia (platelet count <50x109/L) on day 5. The positive and negative predictive values were 74.4 and 91.2%, respectively (power 84.7). CONCLUSIONS: We propose that ALC on admission may be a novel negative predictive factor for severe thrombocytopenia on day 5 to day 7 of DD. Further studies are required to validate our findings and evaluate whether ALC is predictive of other complications of DD.