Dengue Fever: Beyond the Tropics
Dengue Fever: Beyond the Tropics
Dengue virus is hepatotrophic, resulting in liver cell injury and aminotransferase elevation. AST levels are typically higher than alanine aminotransferase levels, possibly related to coexisting myositis and release of AST from injured muscle cells. Aminotransferase levels tend to peak on the ninth day after onset of symptoms and return to normal within 3 weeks of initial infection. Serotypes 3 and 4 are associated with greater aminotransferase elevation. Cholestasis with alkaline phosphatase elevation also may occur.
Thrombocytopenia develops in approximately 50% of patients with dengue fever, and it may be more common in adults than children. The degree of thrombocytopenia correlates with overall vascular leakage and hypoalbuminemia. Significant bleeding is uncommon. Leukopenia also occurs, and with reduction of intravascular volume, azotemia can develop.
Liver biopsies in patients with DHF reveal microvesicular steatosis, centrilobular focal necrosis, acidophilic bodies, Kupffer cell hyperplasia, and mononuclear portal tract inflammation.
The diagnosis of dengue virus infection can be established by a 4-fold rise in antibody titer using a hemagglutination inhibition assay, by the demonstration of immunoglobulin M viral antibody, or by identification of circulating viral RNA by polymerase chain reaction.
Laboratory Findings in Dengue
Dengue virus is hepatotrophic, resulting in liver cell injury and aminotransferase elevation. AST levels are typically higher than alanine aminotransferase levels, possibly related to coexisting myositis and release of AST from injured muscle cells. Aminotransferase levels tend to peak on the ninth day after onset of symptoms and return to normal within 3 weeks of initial infection. Serotypes 3 and 4 are associated with greater aminotransferase elevation. Cholestasis with alkaline phosphatase elevation also may occur.
Thrombocytopenia develops in approximately 50% of patients with dengue fever, and it may be more common in adults than children. The degree of thrombocytopenia correlates with overall vascular leakage and hypoalbuminemia. Significant bleeding is uncommon. Leukopenia also occurs, and with reduction of intravascular volume, azotemia can develop.
Liver biopsies in patients with DHF reveal microvesicular steatosis, centrilobular focal necrosis, acidophilic bodies, Kupffer cell hyperplasia, and mononuclear portal tract inflammation.
The diagnosis of dengue virus infection can be established by a 4-fold rise in antibody titer using a hemagglutination inhibition assay, by the demonstration of immunoglobulin M viral antibody, or by identification of circulating viral RNA by polymerase chain reaction.
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