Sonography in the diagnosis and assessment of dengue Fever

The objective of the following study is to determine the use of ultrasound as an important adjunct to clinical and laboratory profile in diagnosing dengue fever and in predicting the severity of the disease by correlating imaging features with platelet count. The variation in sonographic features seen in patients from different age groups was also studied.

This is a retrospective study. 96 patients who were serologically diagnosed as having dengue fever between April and August 2012 were referred for ultrasound scanning of the abdomen and thorax and the imaging findings were analyzed.

Out of 96 sero-positive dengue cases, 64 (66.7%) patients showed edematous gallbladder (GB) wall thickening, 62 (64.5%) patients showed ascites, 48 (50%) patients had pleural effusion, 17 (17.7%) patients had hepatomegaly, 16 (16.7%) patients had splenomegaly and in 17 (17.7%) patients ultrasound findings were normal. Edematous GB wall thickening, ascites and pleural effusion were the most common combination of findings in all age groups. Edematous GB wall thickening was seen in 97.8% of patients with platelet count of less than 40,000 along with ascites (86.9%) and pleural effusion (58.6%). In patients with platelet count between 40,000 and 80,000 ascites was more common than edematous GB wall thickening. Significantly no abnormal sonographic finding was detected in patient with platelet count more than 150,000.

Sonographic features of thickened GB wall, pleural effusion (bilateral or right side), ascites, hepatomegaly and splenomegaly should strongly favor the diagnosis of dengue fever in patients presenting with fever and associated symptoms, particularly during an epidemic. The degree of thrombocytopenia showed a significant direct relationship to abnormal ultrasound features.