Pathophysiology of dengue hemorrhagic fever please..... i need it for my case study?

Alternative Names
-Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever

Definition
-Dengue hemorrhagic fever is a severe, potentially deadly infection spread by certain mosquitoes (Aedes aegypti ).

Causes
-Four different dengue viruses have been shown to cause dengue hemorrhagic fever. This condition occurs when a person catches a different dengue virus after being infected by another type 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 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 pinpoint spots of blood on the skin (petechiae) and larger patches of blood under the skin (ecchymoses). Bleeding may occur from minor injuries.

Shock may cause death. If the patient survives, recovery begins after a one-day crisis period.

Early symptoms include the following:

Fever
Headache
Muscle aches
Joint aches
Malaise
Decreased appetite
Vomiting

Acute phase symptoms include the following:

Shock-like state
-Sweaty (diaphoretic)
-Cold, clammy extremities

Restlessness followed by:
-Worsening of earlier symptoms
-Petechiae
-Ecchymosis
-Generalized rash

Exams and Tests

Physical examination may reveal the following:

-Low blood pressure
-A weak, rapid pulse
-Rash
-Red eyes
-Red throat
-Swollen glands
-Enlarged liver (hepatomegaly)

Tests may include the following:
-Hematocrit
-Platelet count
-Electrolytes
-Coagulation studies
-Liver enzymes
-Blood gases
-Tourniquet test (causes petechiae below the tourniquet)
-X-ray of the chest (may demonstrate pleural effusion)
-Serologic studies (demonstrate antibodies to Dengue viruses)
-Serum studies from samples taken during acute illness and convalescence (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, the only treatment is to treat the symptoms.

-Rehydration with intravenous (IV) fluids is often necessary to treat dehydration.
-IV fluids and electrolytes are also used to correct electrolyte imbalances.
-A transfusion of fresh blood or platelets can correct bleeding problems.
-Oxygen therapy may be needed to treat abnormally low blood oxygen.

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

-Shock
-Encephalopathy
-Residual brain damage
-Seizures
-Liver damage

When to Contact a Medical Professional
-Call your health care provider if you have symptoms of dengue fever and have been in an area where dengue fever is known to occur.

Prevention
-There is no vaccine available to prevent dengue fever. Use personal protection such as full-coverage clothing, netting, mosquito repellent containing DEET, and if possible, travel during periods of minimal mosquito activity. Mosquito abatement programs can also reduce the risk of infection.