Dengue hemorrhagic fever

Definition

Dengue hemorrhagic fever is a severe, potentially deadly infection spread by mosquitos, mainly the species Aedes aegypti.

Alternative Names

Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever

Causes

Four different dengue viruses are known to cause dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when a person is bitten by a mosquito that is infected with the virus.

There are more than 100 million new cases of dengue fever every year throughout the world. A small number of these develop into dengue hemorrhagic fever. Most infections in the United States are brought in from other countries. Risk factors for dengue hemorrhagic fever include having antibodies to dengue virus from an earlier 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 appears as tiny spots of blood on the skin (petechiae) and larger patches of blood under the skin (ecchymoses). Minor injuries can cause bleeding.

Shock can lead t death. If the patient survives, recovery begins after a one-day crisis period.

Early symptoms include:

• Decreased appetite
• Fever
• Headache
• Joint or muscle aches
• Malaise
• Vomiting

Acute phase symptoms include:

• Restlessness followed by:
  • Ecchymosis
  • Generalized rash
  • Petechiae
  • Worsening of earlier symptoms
• Shock-like state
  • Cold, clammy extremities
  • Sweating

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
• Blood tests (find signs of the virus in the blood) 
• Coagulation studies
• Electrolytes
• Hematocrit
• Liver enzymes
• Platelet count  
• 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

When to Contact a Medical Professional

See your health care provider right away if you have symptoms of dengue fever and have been in an area where dengue fever occurs, and especially if you have had dengue fever before.

Prevention

There is no vaccine to prevent dengue fever. Use personal protection such as full-coverage clothing, mosquito nets, mosquito repellent containing DEET. If possible, travel during times of the day when mosquitos are not so active. Mosquito abatement (control) programs can also reduce the risk of infection.

References

Haile-Mariam T, Polis MA. Viral illnesses. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 128.

Lupi O. Mosquito-borne hemorrhagic fevers. Dermatologic Clinics. 2011;29:33-38.

Vaughn DW, Barrett A, Solomon T. Flaviviruses (Yellow Fever, Dengue, Dengue Hemorrhagic Fever, Japanese Encephalitis, West Nile Encephalitis, St. Louis Encephalitis, Tick-Borne Encephalitis). In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill-Livingstone; 2009:chap 153. 

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