About Medical Management of Dengue Hemorrhagic Fever
Dengue fever affects between 50 and 100 million people each year. The mosquito-borne illness causes seasonal peaks of epidemic infection corresponding to the rainy season of tropical regions in Africa, Asia and the Americas where it is endemic. There are no vaccines for Dengue Fever and treatment is limited to hydration management and supportive care.
Effects
Infection by a dengue virus is predominantly asymptomatic or results in undifferentiated fever. Roughly 10 to 15 percent of those infected will develop more severe illness including Dengue Fever (DF), Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS). Five percent of DHF cases are fatal.
Features
Patients present with: flu-like myalgia, maculopapular or petechial rash, sudden onset fever, postorbital pain, nausea, vomiting and possible signs of hemorrhage or vascular permeability. Disease is often less severe in infants as maternal antibodies may offer transient protection but overall causes higher morbidity and mortality in children under age 15.
Fever may have a characteristic saddleback appearance during the acute phase of infection (5 or fewer days after onset). Fever will resolve after a sudden onset and then reappear in a few days.
Consider dengue fever the causative agent of such symptoms in endemic regions during rainy seasons and periods of mosquito activity. Due to an incubation period of 3 to 14 days, suspect travelers of dengue infection if the onset of fever occurs less than 2 weeks after travel to an endemic region.
Time Frame
Dengue virus has an incubation period of 3 to 14 days, followed by an acute phase lasting approximately 5 days with fever, rash and potential development of more severe forms of the illness. Convalescence lasts up to 3 weeks from onset and is often accompanied by fatigue and depression in adults.
Diagnostic medical management of dengue fever requires collection of two or more blood draws. Draw the first sample upon presentation (during the acute phase) and a second sample during convalescence (6 to 21 days after onset).
Use acute phase samples to check CBC, albumin levels, liver function, viral isolation and serology. Send convalescent samples for serology study by ELISA.
Identification
Base medical management of dengue hemorrhagic fever on empirical clinical findings; physicians rarely receive dengue infection confirmation through viral isolation or serology during acute the acute phase of infection.
Differential diagnosis requires consideration of influenza, malaria, measles, rubella, leptospirosis, meningococcemia, typhoid fever, bacterial sepsis and other viral hemorrhagic fevers.
Blood pressure may be elevated on exam due to dehydration and compromised vascular permeability.
Signs of hemorrhage include petechiae and bleeding from various orifices (vaginal, nasal, oral, anal, aural). According to the Centers for Disease Control, you can perform a tourniquet test by inflating the blood pressure cuff "midway between systolic and diastolic pressure for 5 minutes." Twenty of more petechiae per square inch indicate a positive result.
Patients may exhibit mildly to moderately elevated liver enzymes, specifically aspartame aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (GGT). Bilirubin and alkaline phosphotase may also show elevations.
Warning
Dengue fever patients exhibiting neurological symptoms such as seizures, confusion and lowered consciousness are at higher risk for subsequent development of dengue hemorrhagic fever (DHF).
Watch for signs of impending circulatory failure and shock in patients with dengue hemorrhagic fever (DHF). Danger signs include intense sustained abdominal pain, repeated vomiting, rapid onset of hypothermia following fever and altered mental status.
Considerations
In the medical management of a suspected dengue fever fatality, request collection of fresh tissue samples from the heart, liver, kidney, lungs, intestines, spleen, lymph nodes, brain and skin (from an area exhibiting petechiae) for use in viral isolation and immunohistochemistry. Samples fixed in formalin are not suitable for viral isolation.
Expert Insight
The four flavivirus strains (DEN-1, DEN-2, DEN-3, DEN-4) causing dengue fever do not confer cross-immunity. A prior history of dengue fever infection does not preclude a current case of dengue fever. Co-infection with multiple strains is a distinct possible in endemic regions. Infection or co-infection with hepatitis B or hepatitis C may also lead to similar liver function test results.
Tags: acute phase, viral isolation, dengue fever, during acute, Fever Dengue, Hemorrhagic Fever, hemorrhagic fever