Postural fall in systolic blood pressure is an useful warning sign in Dengue fever

Purpose: Capillary leak is the hallmark of development of severe dengue. A
rise in hematocrit has been a major warning sign in WHO guidelines.
Postural hypotension, which could reflect the intravascular volume
reduction in capillary leak, has been noted as a warning sign in CDC and
Pan American Health Organisation guidelines. We evaluated the diagnostic
accuracy of Postural hypotension as a marker of development of severe
dengue. Methods: 150 patients admitted with dengue fever were recruited in
this prospective observational study. Diagnostic accuracy of conventional
warning signs (abdominal pain, persistent vomiting, fluid accumulation,
mucosal bleeding, lethargy, liver enlargement, increasing hematocrit with
decreasing platelets) and postural hypotension was evaluated. Result: 23
(15.3%) subjects developed severe dengue. Multiple logistic regression
analysis showed that Ascites/Pleural effusion and postural fall in
systolic blood pressure of >10.33% had an odds ratio of
5.024(95%CI:1.11 – 22.75) and 11.369 (95% CI:2.27 – 56.87) respectively.
Other parameters did not reach statistical significance. Sensitivity and
specificity of Ascites/Pleural effusion were 82.6% and 88.2% for
development of severe dengue, whereas postural fall in systolic blood
pressure had sensitivity and specificity of 87% and 82.7%. Conclusion:
These findings present a strong case for including postural hypotension as
a warning sign in patients with dengue fever, especially in
resource-limited settings.