Dengue

Key Features

Essentials of Diagnosis

• Incubation period is 7–10 days

• Sudden onset of high fever, chills, severe myalgias and arthralgias, headache, and retro-orbital pain

• Severe dengue is defined by the presence of plasma leakage, hemorrhage, or organ involvement

• Signs of hemorrhage such as ecchymoses, gastrointestinal bleeding, and epistaxis appear later in the disease

General Considerations

• Four distinct serotypes can cause infection; infection with one serotype does not confer immunity to the others

• Dengue is transmitted primarily from human to human by the bite of the Aedes mosquito

• Healthcare-associated transmission (needlestick or mucocutaneous exposure) and vertical transmission occur rarely

• WHO reports that dengue is currently endemic in more than 100 countries, mostly in tropical and subtropical regions, with about 70% of cases occurring in Asia

• Dengue has been a nationally notifiable condition in the United States since 2010, but although it is endemic in northern Mexico, US outbreaks are uncommon

• As of September 1, 2021, 32 dengue cases had been reported in 2001 in the United States and 367 in US territories (primarily Puerto Rico)

• Case numbers have increased over the last 2 decades; this surge of cases is associated with climatic factors, travel, and urbanization

• When the virus is introduced into susceptible populations, usually by viremic travelers, epidemic attack rates range from 50% to 70%

Clinical Findings

Symptoms and Signs

• Incubation period is usually 7–10 days

• After the incubation period, febrile phase begins abruptly with

  • Nonspecific symptoms

  • High fever

  • Chills

  • Facial flushing

  • Malaise

  • Retroorbital eye pain

  • Generalized body pain

  • Arthralgia

• Some patients might have maculopapular rash, sore throat, and conjunctival injection

• Not all patients have all symptoms or fever

• Mild hemorrhagic manifestations can be seen

• Most of the patients will recover and fever is usually cleared by day 8

• A subset of patients may progress to severe dengue, which is defined by the presence of plasma leakage, hemorrhage, or organ involvement

  • Plasma leakage may be indicated by

    • Hematocrit drop

    • Increasing liver size

    • Persistent vomiting

    • Severe abdominal pain

  • Signs of hemorrhage such as ecchymoses, gastrointestinal bleeding, and epistaxis appear

  • Severe organ involvement may develop such as hepatitis, encephalitis, and myocarditis

• Shock develops when a critical volume of plasma is lost through leakage; the following should raise concern for shock:

  • Decrease in the level of consciousness

  • Hypothermia

  • Hypoperfusion resulting in metabolic acidosis

  • Progressive organ impairment

  • Disseminated intravascular coagulation leading to severe hemorrhage

• Acute kidney injury in dengue largely occurs with shock syndrome and has a high mortality

Differential Diagnosis

• Chikungunya

• Arboviral encephalitides

• Influenza

• Malaria

Diagnosis

• Leukopenia is characteristic

• Elevated transaminases are found frequently

• Thrombocytopenia, fibrinolysis, and hemoconcentration occur more often in the hemorrhagic form of the disease

• Erythrocyte sedimentation ...