Dengue hemorrhagic fever is a severe, potentially fatal infection which occurs when someone with immunity to one type of Dengue virus is infected by another, different type. It is spread by certain mosquitoes ( Aedes aegypti ) that bite primarily during the day. See also Dengue fever .
Alternative Names
Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever
Causes, incidence, and risk factors
Four different dengue viruses have been implicated in both Dengue fever and Dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when the patient contracts a different dengue virus after previous infection(s) by another type. Prior immunity to a different Dengue virus type is important in the production of this severe disease. Worldwide, over 100 million cases of dengue fever occur every year. A small percent develop into dengue hemorrhagic fever. Most cases in the United states are brought in from other countries. It is possible to pass the infection from a traveler in the United States to someone who has not traveled. Risk factors for Dengue hemorrhagic fever include having antibodies to dengue virus from prior infection and being younger than 12, female, or Caucasian.
Signs and tests
Physical examination may show:
Low blood pressure A weak, rapid pulse
Rash Red eyes Red throat Swollen glands Enlarged liver ( hepatomegaly ) Tests:
High hematocrit Low platelet count Electrolytes Coagulation studies High liver enzymes Blood gas to check oxygen content of blood Tourniquet test (tourniquet causes petechiae below the tourniquet)
X-ray of the chest may demonstrate pleural effusion Serologic studies that demonstrate antibodies to Dengue viruses
Acute and convalescent serum (increase in titer to Dengue antigen )
Treatment
Because Dengue hemorrhagic fever is caused by a virus for which there is no known cure or vaccine, only treatment of the symptoms is possible. If the person becomes dehydrated, rehydration with IV ( Intravenous ) fluids is often necessary. IV fluids and electrolytes are also used to correct electrolyte imbalances . A transfusion of fresh blood or platelets can correct bleeding problems, and oxygen therapy may be needed to treat abnormally low blood oxygen.
Expectations (prognosis)
With early and aggressive care, recovery is expected and mortality rates are low. Mortality for untreated patients in shock is approximately 50%.
Calling your health care provider
Call your health care provider if you have symptoms suggestive of Dengue fever and have been in an area where Dengue fever is known to occur.
Prevention
Vaccines are not available to prevent dengue fever . Use personal protection (clothing, mosquito repellent containing DEET, netting, and etc.), and travel during periods of minimal mosquito activity if possible. Mosquito abatement programs can also reduce the risk of infection.