Dengue Fever

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Dengue Fever

 

Last Updated: November 9, 2005

 

Synonyms and related keywords: breakbone fever, ki denga pepo,

mosquito-transmitted viral disease, febrile syndrome, bleeding diathesis,

disseminated intravascular coagulation, DIC, dengue hemorrhagic fever, DHF,

dengue shock syndrome, DSS, dengue viral infections, dengue fever

 

excerpts--

 

Background: 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. Pathophysiology: 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 factors. Frequency:

 

In the US: Between 1990 and 1992, reports of 10 imported cases of dengue

fever were published. While still rare, this is a dramatic increase from 1 case

reported during the period from 1987 to 1989; this probably results from

increases in air travel and an exotic vector that has adapted to cold climates.

Cases along the Texas-Mexico border have been cited recently.

 

Internationally: Dengue virus causes about 100 million cases of acute febrile

disease annually, including more than 500,000 reported cases of DHF/DSS.

Currently, dengue is endemic in 112 countries. The world's largest known

epidemic of DHF/DSS occurred in Cuba in 1981, with more than 116,000 persons

hospitalized and as many as 11,000 cases reported in a single day. Current

outbreaks can be monitored via the ProMed listserve by contacting

owner-promed.

Mortality/Morbidity:

Treated DHF/DSS is associated with a 3% mortality rate.

 

Untreated DHF/DSS is associated with a 50% mortality rate.

Race: Ethnicity is nonspecific, but the disease's distribution is

geographically determined. Fewer cases have been reported in the black

population than in other races. Sex: No predilection is known; however, fewer

cases of DHF/DSS have been reported in men than in women. Age: All ages are

susceptible. In endemic areas, a high prevalence of immunity in adults may limit

outbreaks to children.

 

History:

 

Fever

 

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

 

 

Rash

 

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/DSS

 

 

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

 

Anorexia

 

Abdominal pain (severe in DHF/DSS)

 

Physical:

Fever

 

Signs of intravascular volume depletion

 

Hypotension with narrowed pulse pressure (see Picture 1)

 

 

Delayed capillary refill (see Picture 2)

 

 

Hemorrhagic manifestations

 

Positive tourniquet test

 

 

Petechiae, purpura, epistaxis, gum bleeding, GI bleeding, menorrhagia

 

 

Rash

 

Hepatomegaly (inconsistent)

 

Generalized lymphadenopathy

Causes:

Dengue virus types 1-4

 

Aedes aegypti mosquito vector

 

 

Human-mosquito-human cycle

 

 

Found in tropical regions, especially Southeast Asia

 

http://www.emedicine.com/emerg/topic124.htm

 

 

 

 

 

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Spirituality. " Dave Chief, Grandfather of Red Dog