Dengue And Dengue Hemorrhagic Fever Diagnosis

Diagnosis

• Acute and convalescent serologic testing

Dengue fever is suspected in patients in endemic areas if they develop sudden fever, headache, myalgias, and adenopathy, particularly with the characteristic rash or recurrent fever. Evaluation should rule out alternative diagnoses, especially malaria and leptospirosis.

Diagnostic studies include serologic testing, antigen detection, and PCR of blood. Serologic testing involves hemagglutination inhibiting or complement fixation tests using paired sera, but cross-reactions with other flavivirus antibodies are possible. Antigen detection is available in some parts of the world (not in the US), and PCR is usually done only in laboratories with special expertise. Although rarely done and difficult, cultures can be done using mosquitoes or specialized cell lines in specialized laboratories.

CBC may show leukopenia by the 2nd day of fever; by the 4th or 5th day, the WBC count may be 2000 to 4000/μL with only 20 to 40% granulocytes. Urinalysis may show moderate albuminuria and a few casts.