by http://www.nlm.nih.gov
Dengue hemorrhagic fever is a severe, potentially deadly infection spread by certain species of mosquitoes (Aedes aegypti).
Dengue hemorrhagic fever is a severe, potentially deadly infection spread by certain species of mosquitoes (Aedes aegypti).
Causes
Four different dengue viruses are known to cause dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when a person catches a different type dengue virus after being infected by another one sometime before. Prior immunity to a different dengue virus type plays an important role in this severe disease.
Worldwide, more than 100 million cases of dengue fever occur every year. A small number of these develop into dengue hemorrhagic fever. Most infections in the United States are brought in from other countries. It is possible, but uncommon, for a traveler who has returned to the United States to pass the infection 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.
Symptoms
Early symptoms of dengue hemorrhagic fever are similar to those of dengue fever, but after several days the patient becomes irritable, restless, and sweaty. These symptoms are followed by a shock -like state.
Bleeding may appear as tiny spots of blood on the skin (petechiae) and larger patches of blood under the skin (ecchymoses). Minor injuries may cause bleeding.
Shock may cause death. If the patient survives, recovery begins after a one-day crisis period.
Early symptoms include:
- Decreased appetite
- Fever
- Headache
- Joint aches
- Malaise
- Muscle aches
- Vomiting
Acute phase symptoms include:
- Restlessness followed by:
- Ecchymosis
- Generalized rash
- Petechiae
- Worsening of earlier symptoms
- Shock-like state
- Cold, clammy extremities
- Sweatiness (diaphoretic)
Exams and Tests
A physical examination may reveal:
- Enlarged liver (hepatomegaly)
- Low blood pressure
- Rash
- Red eyes
- Red throat
- Swollen glands
- Weak, rapid pulse
Tests may include:
- Arterial blood gases
- Coagulation studies
- Electrolytes
- Hematocrit
- Liver enzymes
- Platelet count
- Serologic studies (demonstrate antibodies to Dengue viruses)
- Serum studies from samples taken during acute illness and convalescence (increase in titer to Dengue antigen)
- Tourniquet test (causes petechiae to form below the tourniquet)
- X-ray of the chest (may demonstrate pleural effusion)
Treatment
Because Dengue hemorrhagic fever is caused by a virus for which there is no known cure or vaccine, the only treatment is to treat the symptoms.
- A transfusion of fresh blood or platelets can correct bleeding problems
- Intravenous (IV) fluids and electrolytes are also used to correct electrolyte imbalances
- Oxygen therapy may be needed to treat abnormally low blood oxygen
- Rehydration with intravenous (IV) fluids is often necessary to treat dehydration
- Supportive care in an intensive care unit/environment
Outlook (Prognosis)
With early and aggressive care, most patients recover from dengue hemorrhagic fever. However, half of untreated patients who go into shock do not survive.
Possible Complications
- Encephalopathy
- Liver damage
- Residual brain damage
- Seizures
- Shock
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