Dengue Sign, symptoms, its prevention and diagnosis, treatment


Most feared fever particular in tropical countries where its vector mosquitoes are abundant. Dengue (pronounced dengee) fever is a painful, debilitating mosquito-borne disease caused by any one of four closely related dengue viruses.

Prevalence: Each year, an estimated 100 million cases of dengue is reported through out the world. The number of death recorded by these dengue viruses is on the rise particularly in tropical countries like India, Southeast Asia, and Southern China etc.

Dengue fever is transmitted by the bite of an Aedes mosquito infected with a dengue virus. The mosquito becomes infected when it bites a person with dengue virus in their blood. It can’t be spread directly from one person to another person.

How to identify dengue fever?
Dengue is an acute febrile illness of 2 -7 days duration with either two or more of the following manifestations.
Head ache
Retro orbital pain (pain behind the eye)
Hemorrhagic manifestation
Severe joint and muscle pain
Skin rash which appears three to four days after the onset of fever
Mild bleeding (such a nose bleed, bleeding gums, or easy bruising

In children dengue is usually mild. In few cases it may be associated with severe bone pain and its recovery may be associated with prolong depression and fatigue.

Dengue hemorrhagic fever: it is probable case where hemorrhagic is evident by one or more of the following.
 Positive tourniquet test
 Petechiae, ecchymosis or purpura
 Bleeding from mucosa (mostly epistaxis or bleeding from gums), injection sites or other sties
  Haematemesis or melena
Thrombocytopaemia (platelets 100,000/ or less) and

Evidence of plasma leakage due to increased capillary permeability manifested by one or more of the following:
1.       A > 20% rise in haemotocrit for age and sex
2.       A > 20% drop in haemotocrit following treatment with fluids as compared to baseline
3.       Signs of plasma leakage (pleural effusion, ascites or hypoproteinaemia)

 Dengue Shock Syndrome (DSS) All the above criteria of DHF plus signs of circulatory failure manifested by rapid and weak pulse, narrow pulse pressure (< or equal to 20 mm Hg); hypotension for age, cold and clammy skin and restlessness.

 The above descriptions of DF/DHF/DSS are adequate for guiding doctors to treat the disease. However, for reporting of the disease, cases should be classified as suspected DF/DHF/DSS on the basis of above the criteria. Added serological evidence would categorize them into probable and confirmed cases.

How to prevent?
There is no vaccine to prevent dengue fever. The best way to prevent the disease is to prevent bites by infected mosquitoes, particularly if you are living in or traveling to a tropical area. This involves protecting yourself and making efforts to keep the mosquito population down.
To protect oneself
Stay away from heavily populated residential areas, if possible.
Use mosquito repellents, even indoors.
When outdoors, wear long-sleeved shirts and long pants tucked into socks.
When indoors, use air conditioning if available.
Make sure window and door screens are secure and free of holes. If sleeping areas are not screened or air conditioned, use mosquito nets.
If you have symptoms of dengue, speak to your doctor.
To reduce the mosquito population, get rid of places where mosquitoes can breed. These include old tires, cans, or flower pots that collect rain. Regularly change the water in outdoor bird baths and pets' water dishes.
If someone in your home gets dengue fever, be especially vigilant about efforts to protect yourself and other family members from mosquitoes. Mosquitoes that bite the infected family member could spread the infection to others in your home.

How to diagnose Dengue?
Doctors can diagnose dengue infection with a blood test to check for the virus or antibodies to it. If you become sick after traveling to a tropical area, let your doctor know. This will allow your doctor to evaluate the possibility that your symptoms were caused by a dengue infection.
Treatment for Dengue Fever?
There is no specific medicine to treat dengue infection. If you think you may have dengue fever, you should use pain relievers with acetaminophen and avoid medicines with asprin, which could worsen bleeding. You should also rest, drink plenty of fluids, and see your doctor. If you start to feel worse in the first 24 hours after your fever goes down, you should get to a hospital immediately to be checked for complications.
 Do and don’ts for doctors
Cases of Dengue fever/Dengue Hemorrhagic Fever (DF/DHF) should be observed every hour.
 Serial platelet and haematocrit determinations drop in platelets and rise in haematocrits are essential for early diagnosis of DHF.
 Timely intravenous therapy  isotonic crystalloid solution can prevent shock and/or lessen its severity.
 If the patients condition becomes worse despite giving 20ml/kg/hr for one hour, replace crystalloid solution with colloid solution such as Dextran or plasma.
As soon as improvement occurs, replace with crystalloid.
 If improvement occurs, reduce the speed from 20 ml to 10 ml, then to 6 ml, and finally to 3 ml/kg.
 If haematocrit falls, give blood transfusion 10 ml/kg and then give crystalloid IV fluids at the rate of 10ml/kg/hr.
 In case of severe bleeding, give fresh blood transfusion about 20 ml/kg for two hours. Then give crystalloid at 10 ml/kg/hr for a short time (30-60 minutes) and later reduce the speed.
 In case of shock, give oxygen.
For correction of acidosis (sign: deep breathing), use sodium bicarbonate.
 Do not give Aspirin or Brufen for treatment of fever.
 Avoid giving intravenous therapy before there is evidence of haemorrhage and bleeding.
Avoid giving blood transfusion unless indicated, reduction in haematocrit or severe bleeding.
 Avoid giving steroids. They do not show any benefit.
 Do not use antibiotics.
Do not changes the speed of fluid rapidly, i.e., avoid rapidly increasing or rapidly slowing the speed of fluids.
 Insertion of nasogastric tube to determine concealed bleeding or to stop bleeding (by cold
lavage) is not recommended since it is hazardous.
 Stable pulse, blood pressure and breathing rate
Normal temperature
 No evidence of external or internal bleeding
  Return of appetite
  No vomiting
 Good urine output
  Stable haematocrit
 Convalescent confluent petechiae rash
 Absence of fever for at least 24 hours without the use of anti-fever therapy
Return of appetite
 Visible clinical improvement
 Good urine output
 Minimum of three days after recovery from shock
No respiratory distress from pleural effusion and no ascites
 Platelet count of more than 50,000/mm


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