dhf pathophysiology and definition

1. A REPORT ON
DENGUE HEMORRHAGIC FEVER
Submitted By:
Dave Jay S. Manriquez RN.

2. Submitted to:
Dr. Robert Denopol
December 2009
DENGUE HEMORRHAGIC FEVER
Introduction:
Philippine Hemorrhagic Fever was first reported in 1953. In 1958, hemorrhagic
became a notifiable disease in the country and was later reclassified as Dengue Hemorrhagic
Fever. Dengue is primarily a disease of the tropics, and the viruses that cause it are
maintained in a cycle that involves humans and Aedis Aegypti. Infection with dengue viruses
produces a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe
and fatal hemorrhagic disease.
Identification:
A severe mosquito transmitted viral illness endemic in the tropics, much in South and
Southeast Asia especially in the Philippines. It is characterized by increased vascular
permeability, hypovolemia and abnormal blood clotting mechanisms. WHO case definition for
DHF: 1) fever or history of recent fever, 2) thrombocytopenia (platelet count equal to or less
than 100 x 10 /cu mm), 3) hemorrhagic manifestations such as petechiae or overt bleeding
phenomena, and 4) evidence of plasma leakage due to increase vascular permeability.
Illness is biphasic; it begins abruptly with fever, and in children, with mild upper
respiratory complaints often anorexia, facial flush and mild GI disturbances. Coincident with
defervescence and decreasing platelet count, the patient’s condition suddenly worsens, with
marked weakness, severe restlessness, facial pallor and often diaphoresis, severe
abdominal pain and circumoral cyanosis. GI hemorrhage is an ominous prognostic sign that
usually follows a prolonged period of shock.

3. Infectious Agent:
The viruses of dengue fever are flaviviruses and include serotypes 1, 2, 3 and 4
(dengue 1, ­2, ­3, ­4); Chikungunya virus
Occurrence:
Dengue occurrence is sporadic throughout the year. Epidemic usually occurs during
the rainy seasons June – November. Peak months are September and October. It occurs
wherever vector mosquito exists. DHF / DSS are observed most exclusively among children
of the indigenous population under 15 years of age. Occurrence is greatest in the areas of
high Ae. Aegypti prevalence.
Reservoir:
The viruses are maintained in a human Aedes Aegypti mosquito cycle in the tropical
urban centers
Mode of Transmission:
By the bite of infective mosquitoes, principally Ae. Aegypti. This is day biting specie,
with increased biting activity for 2 hours after sunrise and several hours before sunset.
Incubation Period:
From 3 to 14 days, commonly 4­7 days (one week).
Period of Communicability:
Not directly transmitted from person to person. Patients are infective for mosquitoes
from shortly before to the end of the febrile period, usually a period of 3­5 days. The mosquito
becomes infective 8­12 days after the viremic blood meal and remains so for life.

4. Susceptibility and resistance:
All persons are susceptible. Both sexes are equally affected. The age groups
predominantly affected are the preschool age and school age. Adults and infants are not
exempted. Peak age affected 5­9 years.
Susceptibility is universal. Acquired immunity may be temporary but usually
permanent.
Diagnostic Test:
1.) Tourniquet Test (Rumpel Leads Tests)
• Inflate the blood pressure cuff on the upper arm to a point midway between the
systolic and diastolic 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 diagnosis of dengue hemorrhagic fever is made on the basis of the following triad of
symptoms and signs: Hemorrhagic manifestations; a platelet count of less than 100, 000
per cubic millimeter; and objective evidence of plasma leakage, shown either by
fluctuation of packed­cell volume (greater tan 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.
Clinical Manifestations
(Public Health Nursing in the Philippines, 2007):

5. 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.
7th­10th 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
Grading of Dengue Fever:
The severity of DHF is categorized into four grades:
grade I, without overt bleeding but positive for tourniquet test
•
grade II, with clinical bleeding diathesis such as petechiae, epistaxis and hematemesis
•
grade III, circulatory failure manifested by a rapid and weak pulse with narrowing pulse
•
pressure (20 mmHg) or hypotension, with the presence of cold clammy skin and
restlessness; and
• Grade IV, profound shock in which pulse and blood pressure are not detectable. It is
note­worthy that patients who are in threatened shock or shock stage, also known as
dengue shock syndrome, usually remain conscious.
* Grade III and IV are considered to be Dengue Shock Syndrome
MANAGEMENT:
Supportive and symptomatic treatment should be provided:
 Promote rest
 Medication
 Paracetamol – for fever

6.  Analgesic (Acetaminophen (Tylenol) and codeine) – for severe headache and joint
and muscle pains
 Aspirin and nonsteroidal anti­inflammatory drugs should be avoided
Rapid replacement of body fluids is the most important treatment

 Give ORESOL to replace fluid as in moderate dehydration at 75ml/kg in 4­6 hours or
up to 2­3L in adults. Continue ORS intake until paient’s condition improves.
 Intravenous fluid
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:
 Changing water and scrubbing sides of lower vases once a week
 Destroy breeding places of mosquito by cleaning surroundings
 Proper disposal of rubber tires, empty bottles and cans
 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:

7.  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
Sources:
http://www.nscb.gov.ph/secstat/d_vital.asp
http://www.who.int/csr/resources/publications/dengue/012­23.pdf
Public Health Nursing in the Philippines by the Publications Committee, National League of
Philippine Government Nurses, Incorporated