Dengue Shock Syndrome

Dengue shock syndrome (DSS), also mistakenly referred to as dengue hemorrhagic fever (DHF), is characterized by dengue fever's symptoms of abdominal pain, hemorrhage, with the addition of circulatory collapse. Dengue hemorrhagic fever starts unexpectedly with extreme fevers, headache, sore throat, cough, nausea and vomiting. Dengue shock syndrome is the most severe case of dengue fever. The shock occurs after two to six days of symptoms, followed by collapse, weak pulse, and blueness around the mouth. Symptoms also include: easy bruising, blood spots, bleeding gums and nosebleeds. Dengue shock syndrome can be fatal. The mortality rate ranges from 6 to 30 percent, most commonly in children.

Signs and Symptoms

The initial stages of an uncomplicated dengue infection consist of fever (up to 105 degrees Fahrenheit) and severe headache, which can also be accompanied by other symptoms such as chilliness, nausea and vomiting, rash, backache, and severe muscle ache. As the infection progresses into dengue hemorrhagic fever (DHF), the blood and lymph vessels are damaged and bleeding (hemorrhage) from the nose, gums, or under the skin creates purplish bruises. Dengue shock syndrome (DSS), the most severe form of dengue fever, includes all DHF symptoms, as well as its own symptoms. Initial signs of DSS include restlessness, cold clammy skin, rapid weak pulse, and narrowing of pulse pressure and/or hypotension. The more dangerous symptoms include abdominal pain, massive hemorrhage, and circulatory collapse. The most threatening symptom of DSS is circulatory collapse, also known as shock, and it occurs due to the massive loss of fluid between the third and fifth days of illness.

Risk Factors

There are multiple risk factors to acquiring dengue shock syndrome. Mosquitoes are the main transmitters of DSS. Once the aedes albopictus or aedes aegypti feeds on an infected individual the mosquito carries the disease for its entire life. The infected mosquito then feeds on another individual causing them to be infected. However, the most repeatedly seen causes of dengue shock syndrome are the four different dengue virus serotypes (set of antigens with the same characteristics). Each of these serotypes has the ability to initiate dengue shock syndrome. Another general risk factor is geography. Southeast Asia, Africa and the most southern parts of the United States are the most prevalent places to acquire the dengue viruses leading to DSS. Furthermore, dengue shock syndrome has been frequently noticed in children under the age of 10. Dengue can be obtained through the genetic predisposition of the person or passed from mother to baby.

The dengue virus serotypes are named dengue type 1, 2, 3,and 4. The four serotypes are extraordinarily similar, but have different strains of dengue virus. If an individual is infected with one serotype, then s/he has immunity to that virus. However the immunity applies to only that virus not to the others. Exposure to one serotype, in fact causes the individual to be more susceptible to dengue shock syndrome. The immunity produces specific antibodies to prevent the virus from attaching to the macrophage cells, which is the target cell that dengue viruses infect. If an individual is infected with a second serotype of dengue virus the body’s immune system will trigger, thinking that it is the serotype of the first infection. The antibodies attach to the serotype, assuming they are doing their job, however the virus still exist and continues to infect the person. This condition is known as antibody dependent enhancement. The person persists to be infected resulting in dengue hemorrhagic fever and dengue shock syndrome.
Source : Uncle Wikipedia