How Dengue shock occur?

Macrophage and monocyte infection by the Dengue virus sets off a chain of reactions causing release of cytokines and vaso active mediators resulting in increased capillary permeability and leakage of fluid into tissue spaces.

This causes hypotension and shock. If there is excessive bleeding from any site the resulting blood loss may also cause shock. It is believed previous dengue infection with a different serotype facilitates development of these syndromes.

How many types of Dengue are there?

There are four serotypes of Dengue virus. Type 1, 2 ,3 and Type 4. Type2 is more dangerous than other types Serotype 1 followed by serotype 2 seems to more severe than sero type 4 followed by serotype 1.

Clinically Dengue fever can be subclinical, classical, and severe, manifested by Dengue shock syndrome[DSS] and Dengue haemorrhagic fever[DHF].

WHO- has classified Dengue fever into 4 Grades G-1---Fever plus constitutional symptoms and positive tourniquet test. G-2--- Grade 1 plus spontaneous bleeding from Skin, Gums, Nose and GIT G-3-Grade-2 plus circulatory failure and agitation G-4-Grade-3 plus profound shock

Is, there any vaccination against Dengue?

Vaccine is not yet commercially available.

However life attenuated tetravalent vaccine is at an advanced stage of development and have produced promising results in early test.

What is the management of Haemo-Dengue? Why total platelets are preferred instead of whole blood?

Treatment of DHF and DSS is supportive. Patient is closely monitored. Measures are taken to correct hypovolaemia, hypoxia, shock, and DIC. When platelet count falls below 15000/cumm, platelet is transfused. Some physicians do not transfuse platelets unless there is bleeding manifestation.

What medication may be applied for pain fever and vomiting in Dengue ?

We must remember that for pain and fever only paracetamol should be used. Paracetamol can be given in the form of tablets syrup, or suppository.

Tepid water not ice-cold water should be used for sponging. Patients are encouraged to increase their oral fluids intake, if there is vomiting normal saline infusion can be given along with anti-emetics like-domperidone or odansetron.

There is no place for antibiotics and NSAID in the management of Dengue fever.

What damage can Dengue fever cause to liver and kidney?

Generally liver and kidney is not severely affected. There is usually mild elevation of liver enzymes. However severe Dengue can cause hepatic failure and encephalopathy. There can be hypoalbuminaemia, hyponatraemia, and prolonged state of shock can cause acute tubular necrosis of the kidneys.

In Dengue infection what cause fatality?

The grave complications of Dengue fever are Dengue shock syndrome [DSS] and Dengue haemorrhagic  fever [DHF]. Vast majority of Dengue fever patients recover without any complications. With proper treatment the mortality of DSS and DHF can be reduced to 1-2%.

Why we are asked not to use NSAID in Dengue fever? Why Dengue is called

break-bone fever?

NSAID like diclofenac, ibuprofen, or aspirin is not used in dengue fever because the interfere with platelet function. They may also cause gastric erosion and gut bleeding. Although physicians know this, they should exercise caution in prescribing NSAID in any patient with fever of acute onset when diagnosis is not known, because it may turn out to be dengue fever.

Dengue fever causes profound muscle and joints pain there is backache, generalised bodyache, and pain on eye movement, because of severe pain another name for dengue is break-bone fever.

Why we should wait 5-6 days to identify dengue infection through immunological test.?

It takes about 5-6 days for the adequate antibody to develop so test done early in the infection can not detect this antibody.

There is rapid test which takes hours and it detects IgM and IgG antibodies against dengue virus. ELISA is a confirmatory test but it takes 2 days to get the result. PCR can also be used to detect the virus but is not yet available in most centres.

How dengue out break can be prevented?

Dengue out break can be prevented by following measures,

1.     Identification, confirmation and notification of cases of dengue.

2.     Controlling the vector of the disease, AEDES AEGYPTI and AEDES ALBOPICTUS.

3.     The mosquito is a domestic breeder and breeds in water containers, discarded tyres, cocconut shells, flower pots etc. so this larval habitates should be removed.

4.     Ground application of ultralow volume insecticides including fogging and aerial spraying of insecticides.

5.     Health education of the community.

6.     Prevent mosquito bites by using mosquito nets, wearing clothes which covers arms and legs, indoor spray.

7.     Dengue fever patients should be nursed carefully and avoid mosquito bites because mosquitoes became infective after biting a dengue patient.

We hope in future vaccine will be available and anti-viral drugs against dengue will be discovered.