DHF

DHF
Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever

Definition
Dengue hemorrhagic fever is a severe, potentially deadly infection spread by certain species of mosquitoes (Aedes aegypti).
Dengue (DENG-gay) fever is a mosquito-borne disease that occurs in tropical and subtropical areas of the world. Mild dengue fever causes high fever, rash, and muscle and joint pain. A severe form of dengue fever, also called dengue hemorrhagic fever, can cause severe bleeding, a sudden drop in blood pressure (shock) and death.
Millions of cases of dengue infection occur worldwide each year. Dengue fever is most common in Southeast Asia and the western Pacific islands, but the disease has been increasing rapidly in Latin America and the Caribbean.
Researchers are working on dengue fever vaccines, but the best prevention for now is to reduce mosquito habitat in areas where dengue fever is common.
Reservoir
The viruses are maintained in a human aedes egypti mosquito cycle in the tropical urban centers
Incubation Period
From 3-14 days, commonly 4-7 days (one week)
Symptoms
Many people, especially children and teens, may experience no signs or symptoms during a mild case of dengue fever. When symptoms do occur, they usually begin four to 10 days after the person is bitten by an infected mosquito. Signs and symptoms of dengue fever most commonly include:
* Fever, up to 106 F (41 C)
* Headaches
* Muscle, bone and joint pain
* Pain behind your eyes
You might also experience:
* Widespread rash
* Nausea and vomiting
* Minor bleeding from your gums or nose
Most people recover within a week or so. In some cases, however, symptoms worsen and can become life-threatening. Blood vessels often become damaged and leaky, and the number of clot-forming cells in your bloodstream falls. This can cause:
* Bleeding from the nose and mouth
* Severe abdominal pain
* Persistent vomiting
* Bleeding under the skin, which may look like bruising
* Problems with your lungs, liver and heart
*
Clinical Manifestations (Public Health Nursing in the Philippines, 2007):
An acute febrile infection of sudden onset with 3 stages:
• 1st­4th day (febrile or invasive stage)

­high fever, abdominal pain and headache; later flushing which may be accompanied by
vomiting, conjunctiva infection and epistaxis.

• 4th­7th day (toxic or hemorrhagic stage)

­lowering of temperature, severe abdominal pain, vomiting and frequent bleeding from
gastrointestinal tract in the form of hematemesis or melena. Unstable blood pressure,
narrow pulse pressure and shock. Death may occur. Tourniquet test which may be
positive may become negative due to low or vasomotor collapse.

• 7th­1 0th day (convalescent or recovery stage)

­generalized flushing with intervening areas of blanching, appetite regained and blood
pressure already stable.
• Dengue shock syndrome is defined as dengue hemorrhagic fever plus:
*Weak rapid pulse,
*Narrow pulse pressure (less than 20 mm Hg) or, Cold, clammy skin and restlessness

CAUSES
Dengue fever is caused by any one of four dengue viruses spread by mosquitoes that thrive in and near human lodgings. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. When the infected mosquito then bites another person, the virus enters that person’s bloodstream.
After you’ve recovered from dengue fever, you have immunity to the virus that infected you – but not to the other three dengue fever viruses. The risk of developing severe dengue fever, also known as dengue hemorrhagic fever, actually increases if you’re infected a second, third or fourth time.
RISK FACTORS
Factors that put you at greater risk of developing dengue fever or a more severe form of the disease include:
* Living or traveling in tropical areas. Being in tropical and subtropical areas around the world – especially in high-risk areas, such as Southeast Asia, Latin America and the Caribbean – increases your risk of exposure to the virus that causes dengue fever.
* Prior infection with a dengue fever virus. Previous infection with a dengue fever virus increases your risk of having severe symptoms if you’re infected a second time. This is especially true for children.
COMPLICATIONS
If severe, dengue fever can damage the lungs, liver or heart. Blood pressure can drop to dangerous levels, causing shock and, in some cases, death.

Diagnostic Test
1. Tourniquet test (rumpel leads test)
• Inflate the blood pressure cuff on the upper arm to a point midway between the
systol ic and d iastol ic pressure for 5 minutes
• Release cuff and make an imaginary 2.5 cm square or 1 inch just below the cuff, at
the antecubital fossa
• Count the number of petechiae inside the box
• A test is (+) when 2 or more petechiae per 2.5 cm square or 1 inch square are
Observed

2. A con firmed diagnosis is established by culture of the virus, polymerase­chain­reaction (PCR) tests, or serologic assays.

The d iagnosis of dengue hemorrhagic fever is made on the basis of the fol lowing triad of
symptoms and signs: Hemorrhagic manifestations; a platelet count of less than 1 00, 000
per cubic m i l l imeter; and objective evidence of plasma leakage, shown either by
fluctuation of packed­cel l volume (greater than 20 percent during the course of the illness)
or by clinical signs of plasma leakage, such as pleural effusion, ascites or
hypoproteinemia. Hemorrhagic manifestations without capillary leakage do not constitute
dengue hemorrhagic fever.

MANAGEMENT:

Supportive and symptomatic treatment should be provided:
? Promote rest
? Medication

> Paracetamol – for fever
> Analgesic (Acetaminophen (Tylenol) and codeine) – for severe headache and joint
muscle pains
> Aspirin and nonsteroidal anti­inflammatory drugs should be avoided

? Rapid replacement of body flu ids is the most important treatment
> Give ORESOL to replace flu id as in moderate dehydration at 75m l/kg in 4­6 hours or
up to 2­3L in adults. Continue ORS intake until patient’s condition improves.
> Intravenous flu id
? For hemorrhage
> Keep patient at rest during bleeding periods
> For epistaxis – maintain an elevated position of trunk and promote vasoconstriction in
nasal mucosa membrane through an ice bag over the forehead.
> For melena – ice bag over the abdomen.

? Provide support during the transfusion therapy
? Diet
> Low fat, low fiber, non­irritating, non­carbonated
> Noodle soup may be given
? Observe signs of deterioration (shock) such as low pulse, cold clammy perspiration,
prostration.
? For shock
> Place in dorsal recumbent position to facilitate circulation
> Provision of warmth through lightweight covers (overheating causes vasodilation
which aggravates bleeding)

PREVENTION:
The best way to prevent dengue fever is to take special precautions to avoid contact with
mosquitoes.

? Eliminate vector by:
o Changing water and scrubbing sides of lower vases once a week
o Destroy breeding places of mosquito by cleaning surroundings
o Proper disposal of rubber tires, empty bottles and cans
o Keep water containers covered
Because Aedes mosquitoes usually bite during the day, be sure to use precautions
especially during early morning hours before daybreak and in the late afternoon before dark.

Other precautions include:

? When outdoors in an area where dengue fever has been found
> Use a mosquito repellant containing DEET, picaridin, or oil of lemon eucalyptus
> Dress in protective clothing­long­sleeved shirts, long pants, socks, and shoes
? Keeping unscreened windows and doors closed
? Keeping window and door screens repaired
? Use of mosquito nets