How do you know if you have dengue fever?

Continuing from my previous post, how do the doctors find out if we have dengue fever?
The classic picture is high fever with no localising source of infection, a petechial rash with thrombocytopenia and relative leukopenia - low platelet and white blood cell count. Care has to be taken as diagnosis of DHF can mask end stage liver disease and vice versa.
The WHO definition of dengue haemorrhagic fever has been in use since 1975; all four criteria must be fulfilled:
1.Fever, bladder problem, constant headaches, severe dizziness and loss of appetite.

2.Hemorrhagic tendency (positive tourniquet test, spontaneous bruising, bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody diarrhea)

3.Thrombocytopenia (<100,000 platelets per mm³ or estimated as less than 3 platelets per high power field)

4.Evidence of plasma leakage (hematocrit more than 20% higher than expected, or drop in haematocrit of 20% or more from baseline following IV fluid, pleural effusion, ascites, hypoproteinemia)

5.Encephalitic occurences.


Dengue shock syndrome is defined as dengue hemorrhagic fever plus:
•Weak rapid pulse,
•Narrow pulse pressure (less than 20 mm Hg)
•Cold, clammy skin and restlessness.

Serology and polymerase chain reaction (PCR) studies are available to confirm the diagnosis of dengue if clinically indicated.

Have you ever wondered what had caused the deadly type of dengue fever- dengue haemorrahgic fever?

(1)Virulent strain theory and Antibody enhancement Some strains are more virulent than others (DEN-2). All 4 strains are different but there are some similarities. With prior infection (eg Den-1), the antibodies are able to recognize DEN-2 (current infection). This had caused the body to over response. The immune cell produces too much chemicals, which causes the plasma in the blood to leak out due to the inflammation which leads to low blood pressure and lastly SHOCK!

(2)Due to Severe acute respiratory syndrome


Lastly, there is no drugs and workable vaccines to cure Dengue Fever yet and hence the best way is to prevent yourself from getting it, which will be explained in another post. Chill out for now =)

By Amas Goh