dengue
DENGUE
Treatment Guideline Chart

Dengue infection is caused by the dengue virus that belongs to the family Flaviviridae. It is generally self-limiting and rarely fatal.
There are 4 serotypes (DEN-1, DEN-2, DEN-3, DEN-4). Infection with dengue serotype confers lifetime protective immunity to that specific serotype; cross-protection for other serotypes is only short-term.
It is transmitted to humans through the bites of infected Aedes mosquitoes. It is primarily transmitted by female Aedes aegypti, a tropical and subtropical species. Humans and monkeys are the amplifying hosts after the mosquito bite.
After 4-10 days of incubation period, illness begins immediately.
The acute phase of illness lasts for 3-7 days, but the convalescent phase may be prolonged for a week and may be associated with weakness and depression especially in adults.

Dengue Signs and Symptoms

Introduction

Dengue Fever (DF)

  • Dengue fever is generally a self-limiting and is rarely fatal
  • The acute phase of illness lasts for 3-7 days, but the convalescent phase may be prolonged for a week and may be associated with weakness and depression especially in adults

Dengue Hemorrhagic Fever (DHF)

  • During the acute phase of illness, it is difficult to distinguish DHF from DF and other febrile illnesses; thus, accurate diagnosis can only be made once fever remits
    • Major differentiating changes include abnormal hemostasis and plasma leakage into the abdominal and pleural cavities

Etiology

  • Etiologic agent: Dengue virus, from the family Flaviviridae
    • 4 serotypes: DEN-1, DEN-2, DEN-3 and DEN-4
    • Infection with a dengue serotype confers lifelong immunity to that specific serotype; cross-protection for other serotypes is only short term
  • Vector: Aedes (Stegomyia) mosquitoes
  • Transmission: Humans and monkeys are the amplifying hosts after a mosquito bite
  • Incubation period
    • Extrinsic (within mosquito vector): 8-10 days
    • Intrinsic (within human host): 3-14 days (average of 4-7 days)

Signs and Symptoms

Dengue Fever (DF)

  • Older children and adults:
    • Mild febrile syndrome or high fever with abrupt onset, may be biphasic (high fever that becomes normal then recurs to its previous degree) and usually lasts for 2-7 days
    • Severe headache, pain behind the eyes, general malaise, muscle or joint pains, nausea and vomiting, rash
    • Hemorrhagic manifestations eg epistaxis, gingival bleeding, hematuria, menorrhagia, skin hemorrhages (petechiae, purpura, ecchymoses), gastrointestinal (GI) bleeding (hematemesis, melena, hematochezia)
  • Infants and young children: Undifferentiated fever and maculopapular rash are common

Atypical Presentation

  • Acute abdominal pain, diarrhea, severe GI hemorrhage
  • Severe headache, convulsions, altered sensorium
  • Encephalitic signs associated with or without intracranial hemorrhage
  • Irregular pulse and heart rate
  • Respiratory distress
  • Fulminant hepatic failure, obstructive jaundice, raised liver enzymes, Reye syndrome
  • Acute renal failure
  • Disseminated intravascular coagulation (DIC)
  • Vertical transmission in newborns

Dengue Hemorrhagic Fever (DHF)

  • The critical stage in DHF is at the time of defervescence, ie the phase of plasma leakage, but signs of circulatory failure or hemorrhagic manifestations may occur from about 24 hours before to 24 hours after the temperature falls to normal
  • 4 major clinical manifestations
    • High fever
    • Hemorrhagic phenomena: Scattered petechiae are the most common hemorrhagic manifestations
    • Hepatomegaly
    • Circulatory failure
  • In children, the following may be observed:
    • Sudden rise in body temperature accompanied by facial flush
    • Nonspecific constitutional symptoms resembling DF eg anorexia, vomiting, headache and muscle or bone and joint pain
    • Epigastric discomfort, tenderness at the right costal margin and generalized abdominal pain
    • Fever of 40-41°C and febrile convulsions in infants

Dengue Shock Syndrome (DSS)

  • Circulatory failure
    • Skin becomes cool, blotchy and congested
    • Circumoral cyanosis
    • Rapid, weak pulse with narrowing of the pulse pressure
    • Hypotension with cold clammy skin
  • May initially be lethargic then becomes restless and rapidly enters a critical stage of shock
  • Acute abdominal pain
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