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Thursday, February 8, 2007

Dengue Hemorrhagic Fever (DHF) -- Signs, Symptoms and Treatment

Signs and Symptoms

Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death.

The clinical features of dengue fever vary according to the age of the patient. Infants and young children may have a non-specific febrile illness with rash. Older children and adults may have either a mild febrile syndrome or the classical incapacitating disease with abrupt onset and high fever, severe headache, pain behind the eyes, muscle and joint pains, and rash.

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

This infectious disease is manifested by a sudden onset of fever, with severe headache, muscle and joint pains (myalgias and arthralgias — severe pain gives it the name break-bone fever or bonecrusher disease) and rashes; the dengue rash is characteristically bright red petechia and usually appears first on the lower limbs and the chest - in some patients, it spreads to cover most of the body. There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting or diarrhea.

Dengue haemorrhagic fever is a potentially deadly complication that is characterized by high fever, haemorrhagic phenomena--often with enlargement of the liver--and in severe cases, circulatory failure. The illness commonly begins with a sudden rise in temperature accompanied by facial flush and other non-specific constitutional symptoms of dengue fever. The fever usually continues for two to seven days and can be as high as 40-41°C, possibly with febrile convulsions and haemorrhagic phenomena.

Some cases develop much milder symptoms, which can, when no rash is present, be misdiagnosed as the flu or other viral infection. Thus, travelers from tropical areas may inadvertently pass on dengue in their home countries, having not being properly diagnosed at the height of their illness. Patients with dengue can only pass on the infection through mosquitoes or blood products while they are still febrile.

The classic dengue fever lasts about six to seven days, with a smaller peak of fever at the trailing end of the fever (the so-called "biphasic pattern"). Clinically, the platelet count will drop until the patient's temperature is normal.

In moderate DHF cases, all signs and symptoms abate after the fever subsides. Cases of DHF also shows higher fever, haemorrhagic phenomena, thrombocytopenia and haemoconcentration. A small proportion of cases leads to dengue shock syndrome (DSS) which has a high mortality rate. In severe cases, the patient's condition may suddenly deteriorate after a few days of fever; the temperature drops, followed by signs of circulatory failure, and the patient may rapidly go into a critical state of shock and die within 12-24 hours, or quickly recover following appropriate volume replacement therapy.

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.

  • The mainstay of treatment is supportive therapy. The patient is encouraged to keep up oral intake, especially of oral fluids.
  • 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. But the transfusion is recommendable on platelet count falling below 20,000 without hemorrhage / bleeding or approx 50,000 with hemorrhage/bleeding. Internal bleeding indicated by dark color of stools, other bleedings indicated at surface as red rashes all over or most of the body parts. A platelet transfusion is rarely indicated if the platelet level drops significantly or if there is significant bleeding.
  • Oxygen therapy may be needed to treat abnormally low blood oxygen.

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