Over the past 20 years, dengue haemorrhagic fever (DHF) has been the subject of intensive epidemiological, clinical, virological and immunological investigations. Considerable debate and controversy have surrounded its causation and the probable role of immunological mechanisms in its pathogenesis. The exact cause of DHF is still uncertain and this article reviews current thinking about the problem.
Matched MeSH terms: Severe Dengue/physiopathology*
Dengue fever (DF) is an acute febrile viral disease frequently presented with headache, bone or joint and muscular pains, and rash. A significant percentage of DF patients develop a more severe form of disease, known as dengue haemorrhagic fever (DHF). DHF is the complication of DF. The main pathophysiology of DHF is the development of plasma leakage from the capillary, resulting in haemoconcentration, ascites, and pleural effusion that may lead to shock following defervescence of fever. Therefore, accurate prediction of the day of defervescence of fever is critical for clinician to decide on patient management strategy. To date, no known literature describes of any attempt to predict the day of defervescence of fever in DF patients. This paper describes a non-invasive prediction system for predicting the day of defervescence of fever in dengue patients using artificial neural network. The developed system bases its prediction solely on the clinical symptoms and signs and uses the multilayer feed-forward neural networks (MFNN). The results show that the proposed system is able to predict the day of defervescence in dengue patients with 90% prediction accuracy.
Matched MeSH terms: Severe Dengue/physiopathology*
Real-time monitoring and precise diagnosis of the severity of Dengue infection is needed for better decisions in disease management. The aim of this study is to use the Bioimpedance Vector Analysis (BIVA) method to differentiate between healthy subjects and severe and non-severe Dengue-infected patients. Bioimpedance was measured using a 50 KHz single-frequency bioimpedance analyzer. Data from 299 healthy subjects (124 males and 175 females) and 205 serologically confirmed Dengue patients (123 males and 82 females) were analyzed in this study. The obtained results show that the BIVA method was able to assess and classify the body fluid and cell mass condition between the healthy subjects and the Dengue-infected patients. The bioimpedance mean vectors (95% confidence ellipse) for healthy subjects, severe and non-severe Dengue-infected patients were illustrated. The vector is significantly shortened from healthy subjects to Dengue patients; for both genders the p-value is less than 0.0001. The mean vector of severe Dengue patients is significantly shortened compare to non-severe patients with a p-value of 0.0037 and 0.0023 for males and females, respectively. This study confirms that the BIVA method is a valid method in differentiating the healthy, severe and non-severe Dengue-infected subjects. All tests performed had a significance level with a p-value less than 0.05.
BACKGROUND: Difficulties in the classification of dengue infection have been documented. Such difficulties could be due to the low awareness of the World Health Organization diagnostic guidelines among clinicians.
OBJECTIVE: To study the diagnostic practices of clinicians in classifying patients as dengue fever (DF) or dengue haemorrhagic fever (DHF)/dengue shock syndrome (DSS) at the time of discharge during an outbreak.
METHODS: A prospective descriptive study of clinical features and disease classification in adult and pediatric dengue patients in the University of Malaya Medical Centre.
RESULTS: Five hundred and twenty adult and 191 pediatric patients were enrolled. Thrombocytopenia and evidence of plasma leakage were present in 8% of adult and 19% of pediatric patients. Of these, 93% and 49%, respectively, were given the discharge diagnoses of DF instead of DHF/DSS. Hemoconcentration, serous effusion and thrombocytopenia were not recognized in clinicians' discharge diagnosis of DHF/DSS for adult patients. The receiver operating characteristic (ROC) curve suggested a lack of consistency in the use of WHO guidelines in establishing DHF/DSS in adult patients, while implying otherwise for pediatric patients.
CONCLUSION: DHF/DSS is an under-recognized condition by clinicians managing these patients. This can affect the case fatality rate of DHF/DSS and the economic burden of the disease. The lack of awareness in disease manifestations especially plasma leakage, can lead to delayed recognition of DHF/DSS.
Study site: Outpatient department and inpatients, adult medical and pediatric wards, University Malaya Medical Center (UMMC), Kuala Lumpur, Malaysia
Prospective evaluation of repeated standard tourniquet testing as a diagnostic indicator of dengue infection was done. Included were patients admitted to a children's hospital in Kuala Lumpur on a clinical suspicion of dengue infection based on the World Health Organization (WHO) criteria. A standard method of tourniquet was performed on 79 patients on a daily basis following admission. subjects and negative in the remaining 14 subjects. Fifty-eight subjects were serologically confirmed cases, 4 indeterminate and the remaining 17 subjects had negative serology. For diagnostic classification, 13 had dengue fever, 49 with dengue haemmorhagic fever (DHF) while 17 had non-dengue infection. The sensitivity and specificity of the tourniquet test was 82.8% and 23.5% respectively. The positive predictive value (PPV) was 78.7% while the negative predictive value (NPV) was 28.6%. In addition, the tourniquet test aided in the diagnosis of one-fifth of patients with DHF, who presented with a positive tourniquet test as the only bleeding manifestation. It seems that in a hospital setting, the tourniquet test adds little to the diagnosis of dengue infection/DHF. A positive tourniquet test, repeatedly performed, was found clinically useful as a preliminary screening test in dengue infection as recommended by WHO. However, it was not very specific and had a high false positive rate.
The impact of dengue on liver function was studied on fifty serologically confirmed dengue cases admitted to Hospital Universiti Kebangsaan Malaysia (HUKM). Twenty-five of these patients had classic dengue fever (DF) and 25 had grade 1 or 2 dengue hemorrhagic fever (DHF). There were more (60%) DHF patients with hepatomegaly compared to DF (40%) but the difference was not statistically significant. Analysis of the liver profile showed that liver dysfunction was commoner in DHF compared to DF, indicating that the degree of liver impairment may be related to the severity of DHF. Hyperbilirubinemia was noted in 3 (12%) DHF and 2 (8%) DF patients. The mean (range) serum bilirubin was higher in DHF [14.2(5-50) micromol/l] compared to DF [10.9(5-30) micromol/l)] (p > 0.05). Elevated levels of serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were observed more frequently in DHF (20 and 12 patients respectively) compared to DF (16 and 8 patients respectively). Nine (36%) DHF and 6 (24%) DF patients had concomitant elevation of ALT and ALP levels. The mean (range) serum ALT levels were 109.3(23-325) U/l in DHF and 90.8(13-352) U/l in DF (p > 0.05). The mean (range) serum ALP levels were 102.2(15-319) U/l in DHF and 93.3(34-258) U/l in DF (p > 0.05). The ALT and ALP levels were significantly higher in DHF patients with spontaneous bleeding than those without bleeding (p < 0.05) None of the patients developed fulminant hepatitis. The immunoregulatory cells, which include the T (CD3), B (CD 19), CD4, CD8, CD5 and natural killer (NK) cells were significantly lower in DHF compared to DF patients (p < 0.05). However, the reduction in these cell counts did not correlate with the liver dysfunction seen in DHF patients. In conclusion, hepatomegaly and liver dysfunction were commoner in DHF compared to DF.
Matched MeSH terms: Severe Dengue/physiopathology*