Dengue Fever: Prognostic Insights From a Complete Blood Count

Abstract

Introduction Dengue fever is endemic in more than 100 countries. Early indicators of prognosis are vital to reduce the fatality rate associated with dengue fever. The objective of this study is to investigate the value of a complete blood count (CBC) in determining the prognosis of dengue fever. Methodology This was a retrospective study of all patients admitted to Chigateri General and Bapuji hospitals, Davangere over two months. Fifty-six patients were included in the study. Medical records were accessed to obtain data on the clinical profile and laboratory investigations. Results Thrombocytopenia was the most common hematological feature, in 50 cases (~90%), followed by leukopenia in 43 cases (~76%). The duration of hospital stay ranged from two to seven days. Interestingly, the percentage of lymphocytes in the differential leukocyte count at the time of admission showed a significant negative correlation with the duration of hospital stay (p=0.028). Also, three distinct trends were observed in the sequence of recovery of platelets and white blood cells (WBCs). Discussion A repertoire of prognostic indicators have been described to predict the course and outcome of dengue fever: liver enzymes, interleukins 4 and 10, tumor necrosis factor α (TNFα), some proteases, soluble adhesion molecules, the surface area of atypical lymphocytes, high fluorescent lymphocyte counts, immature granulocytes and immature platelet factor (IPF). However, these markers are not routinely employed due to financial constraints and lack of infrastructure. The percentage of lymphocytes in the differential leukocyte count performed at the time of admission predicted the length of hospital stay. The higher the percentage of lymphocytes, the faster the recovery from dengue and shorter the duration of stay in the hospital. This is particularly important in remote areas with limited laboratory facilities. High-risk patients can be referred to a higher centre before they develop complications of the disease. Conclusion The complete blood count can function as an early indicator of prognosis in dengue fever even in areas where sophisticated biomedical infrastructure is lacking. The lymphocyte percentage on admission could significantly predict the length of hospital stay.

Keywords: complete blood count; cost effective; dengue; lymphocyte; mortality; primary care; prognosis.

Figure 1. Incidence of Dengue Fever in India and Karnataka

Figure 2. Sample size after application of exclusion criteria

Figure 3. Presenting complaints of patients

Figure 4. Duration of Fever

Figure 5. Line fit plot showing the association of Lymphocyte percentage in the differential count and the duration of hospital stay

Figure 6. Trends in the recovery of white blood cells (WBCs) and platelets

Figure 7. White blood cell (WBC) recovery in relation to platelets