Friday, January 26, 2007


Prehospital Care
-Initiate supportive therapy
-Intravenous (IV) crystalloids, as needed to keep systolic blood pressure above 90 mm Hg
O2, empirically

Emergency Department Care
-Supportive therapy
-IV access, O2, and monitoring are helpful.
-IV crystalloids may be necessary for hypotension; central line may be needed.
-Correct electrolyte abnormalities and acidemia.
-Implement therapy for DIC if indicated.
-Corticosteroids are not helpful.No antiviral therapy is available

Sign and Symptom

From History Taking:

-Abrupt onset, rising to 39.5-41.4°C
-Accompanied by frontal or retro-orbital headache
-Lasts 1-7 days, then defervesces for 1-2 days
-Biphasic, recurring with second rash but not as high

-Initial rash transient, generalized, macular, and blanching; occurs in first 1-2 days of fever
-Second rash occurring within 1-2 days of defervescence, lasting 1-5 days
-Second rash morbilliform, maculopapular, sparing palms and soles
-Occasionally desquamates

Bone pain
-Absent in DHF(dengue haemorrhagic fever) / DSS (dengue shock syndrome)
-After onset of fever
-Increases in severity
-Not associated with fractures
-May last several weeks
-Most common in legs, joints, and lumbar spine

Miscellaneous symptoms
-Nausea and vomiting
-Cutaneous hyperesthesia
-Taste aberrations
-Abdominal pain (severe in DHF/DSS)

From Physical Examination:

-Signs of intravascular volume depletion
-Hypotension with narrowed pulse pressure

-Delayed capillary refill

-Hemorrhagic manifestations
-Positive tourniquet test
-Petechiae, purpura, epistaxis, gum bleeding, GI bleeding, menorrhagia
-Hepatomegaly (inconsistent)
-Generalized lymphadenopathy



Dengue viral infections frequently are not apparent. Classic dengue primarily occurs in nonimmune, nonindigenous adults and children. Symptoms begin after a 5- to 10-day incubation period. DHF/DSS usually occurs during a second dengue infection in persons with preexisting actively or passively (maternally) acquired immunity to a heterologous dengue virus serotype. Illness begins abruptly with a minor stage of 2-4 days' duration followed by rapid deterioration. Increased vascular permeability, bleeding, and possible DIC may be mediated by circulating dengue antigen-antibody complexes, activation of complement, and release of vasoactive amines. In the process of immune elimination of infected cells, proteases and lymphokines may be released and activate complement coagulation cascades and vascular permeability.

The grade of fever
Low grade fever: 37.3~38 C
Moderate fever: 38~39 C
High fever: 39.1~41 C
Hyperthermia fever: more than 41 C
-Fever to 106°F (41.1°C), which a healthy adult body can tolerate for several hours.
-The brain's thermostat will stop the fever from climbing above 106° (41.1C)
-Cells do not die off until 110°F (43.3°C) is reached.

Background/ History

History of Dengue

The first reported epidemics of DF occurred in 1779-1780 in Asia, Africa, and North America. The near simultaneous occurrence of outbreaks on three continents indicates that these viruses and their mosquito vector have had a worldwide distribution in the tropics for more than 200 years. During most of this time, DF was considered a mild, nonfatal disease of visitors to the tropics. Generally, there were long intervals (10-40 years) between major epidemics, mainly because the introduction of a new serotype in a susceptible population occurred only if viruses and their mosquito vector could survive the slow transport between population centers by sailing vessels.
A pandemic of dengue began in Southeast Asia after World War II and has spread around the globe since then. Epidemics caused by multiple serotypes (hyperendemicity) are more frequent, the geographic distribution of dengue viruses and their mosquito vectors has expanded, and DHF has emerged in the Pacific region and the Americas. In Southeast Asia, epidemic DHF first appeared in the 1950s, but by 1975 it had become a frequent cause of hospitalization and death among children in many countries in that region.

Thursday, January 25, 2007


Dengue has been called the most important mosquito-transmitted viral disease in terms of morbidity and mortality. Dengue fever is a benign acute febrile syndrome occurring in tropical regions. In a small proportion of cases, the virus causes increased vascular permeability that leads to a bleeding diathesis or disseminated intravascular coagulation (DIC) known as dengue hemorrhagic fever (DHF). Secondary infection by a different dengue virus serotype has been confirmed as an important risk factor for the development of DHF. In 20-30% of DHF cases, the patient develops shock, known as the dengue shock syndrome (DSS). Worldwide, children younger than 15 years comprise 90% of DHF subjects; however, in the Americas, DHF occurs in both adults and children.

Dengue is a homonym for the African ki denga pepo, which appeared in English literature during an 1827-28 Caribbean outbreak. The first definite clinical report of dengue is attributed to Benjamin Rush in 1789, but the viral etiology and its mode of transmission via mosquitos were not established until the early 20th century.

Dengue (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4), of the genus Flavivirus. Infection with one of these serotypes provides immunity to only that serotype for life, so persons living in a dengue-endemic area can have more than one dengue infection during their lifetime. DF and DHF are primarily diseases of tropical and sub tropical areas, and the four different dengue serotypes are maintained in a cycle that involves humans and the Aedes mosquito. However, Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans, is the most common Aedes species. Infections produce a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. Important risk factors for DHF include the strain of the infecting virus, as well as the age, and especially the prior dengue infection history of the patient.