Clinical features

Infection by any of the four dengue serotypes may lead to symptomatic infections or asymptomatic seroconversion (1)

• asymptomatic infection
  • around half of patients with dengue infection have no clinical signs or symptoms of disease.
• symptomatic infection
  • is a systemic and dynamic disease with a wide clinical spectrum that includes both severe and non severe clinical manifestations
  • severe disease usually follows three phases – febrile, critical and recovery
  • the severity of the disease usually becomes apparent around defervescence e.g. – during the transition from the febrile to afebrile phase (around the time of the onset of the critical phase)
  • can be divided into
    • undifferentiated fever
      • presents with fever and mild non-specific symptoms which may mimic other viral infections
      • do not meet case definition criteria for DF
      • typically young children or those experiencing their first infection (may also occur during a secondary infection)
      • usually recover fully without need for hospital care
    • classic dengue fever (DF)
    • more severe forms of the disease - haemorrhagic fever (DHF) and dengue shock syndrome (DSS) (1,2)

Abrupt onset of symptoms occur after an incubation period of 3-14 days (average 7 days).

• fever
  • characteristic feature of the infection with high spikes of 39.4-40.5°C
  • maybe seen as biphasic with a fluctuating body temperatures or as low grade fever over five to seven days
  • may result in febrile seizures or delirium in young children
• aches and pains
  • frequent backache, arthralgia, myalgia, and bone pain are common
  • constant headache seen towards the front of the head is typical which resolves within a few days
  • severe retro-orbital pain with eye movement or with a little pressure applied to the eyeball
• gastrointestinal symptoms
  • anorexia, nausea or vomiting, epigastric discomfort or pain
  • lack of appetite or changes to taste sensation
• lethargy or restlessness
• collapse, or dizziness
• upper respiratory tract symptoms such as cough, sore throat may atypically occur in mild infection (3)

Signs present in dengue infection are:

• diffuse skin flushing of the face, neck, and chest
  • on day 3 or 4 of the fever, skin flushing may progress into maculopapular or rubelliform rash
  • blanching of the skin may be present
  • rash fades with time and appear as pallid areas during the convalescent phase
• haemorrhagic signs
  • petechiae, purpura
  • positive tourniquet test
    • record patient’s blood pressure
    • inflate the cuff to a point midway between SBP and DBP and maintain for 5 minutes
    • the test is positive when 10 or more petechiae per 1 square inch appear in the forearm (below antecubital fossa)
    • epistaxis, gingival bleeding, haematemesis, melaena, vaginal bleeding (in women of childbearing age), or bleeding from a venepuncture site indicates major haemorrhages
  • these signs may be observed in either dengue fever or dengue haemorrhagic fever.
• heaptomegaly
• ascites, postural dizziness, or pleural effusion – indicates plasma leakage seen in dengue haemorrhagic fever
• circulatory collapse – supports a diagnosis of dengue shock syndrome
  • cold clammy skin
  • rapid and weak pulse with narrowing of pulse pressure <20 mm Hg with decreased diastolic pressure
  • postural drop of blood pressure >20 mm Hg
  • capillary refill time greater than three seconds
  • reduced urine output (3)

Reference:

• (1) World Health Organization (WHO) 2012. Handbook for clinical management of dengue
• (2) Bhatt S et al. The global distribution and burden of dengue. Nature. 2013;496(7446):504-7
• (3) Kularatne SA. Dengue. BMJ. 2015;351:h4661
• (4) Centers for Disease Control and Prevention (CDC). Dengue. Clinical guidance