Background: Although plasma leakage is the major cause of mortality and morbidity in patients with dengue hemorrhagic fever (DHF), a detailed assessment of the natural course of this process is still lacking. We employed serial ultrasound examination to delineate the locations and the timing of plasma leakage and to evaluate the usefulness of ultrasound in detecting plasma leakage in DHF.
Method: Daily ultrasound examinations of the abdomen and right thorax were performed in 158 suspected dengue cases to detect ascites, thickened gall bladder wall and pleural effusions. Cases were classified into dengue fever (DF), DHF or other febrile illness (OFI) based on serology and evidence of plasma leakage including hemoconcentration and pleural effusion detected by chest radiograph.
Results: Ultrasonographic evidence of plasma leakage was detected in DHF cases starting from 2 days before defervescence and was detected in some cases within 3 days after fever onset. Pleural effusion was the most common ultrasonographic sign of plasma leakage (62% of DHF cases one day after defervescence). Thickening of the gallbladder wall and ascites were detected less frequently (43% and 52% of DHF cases respectively) and resolved more rapidly than pleural effusions. The size of pleural effusions, ascites and gall bladder wall thickness in DHF grade I and II were smaller than those of grade III patients. Ultrasound detected plasma leakage in 12 of 17 DHF cases who did not meet the criteria for significant hemoconcentration.
Conclusions: Ultrasound examinations detected plasma leakage in multiple body compartments around the time of defervescence. Ultrasonographic signs of plasma leakage were detectable before changes in hematocrits. Ultrasound is a useful tool for detecting plasma leakage in dengue infection.