ANATOMY AND PHYSIOLOGY

Blood has always fascinated humans, and

historically there has been much speculation about

its function. Blood was considered the “essence of

life” because the uncontrolled loss of it can result

in death. Blood is pumped by the heart through

the blood vessels, which extend throughout the

body. Blood helps to maintain homeostasis on

several ways: 1. transport of gases, nutrients and waste products, 2.

transport of processed molecules, 3. transport of regulatory molecules, 4.

regulation of pH and osmosis, 5. maintenance of body temperature, 6.

protection against foreign substances and 7. clot formation.

Blood is a type of connective tissue that consists of cell and cell

fragments are the formed elements, and the liquid is the plasma. The formed

elements account for slightly less than half and plasma accounts for slightly

more than half the total blood volume. The total blood volume in the average

adult is about 4-5L in females and 5-6L in males. Blood makes up about 8% of

total body weight.

Plasma is a pale yellow fluid that consists of about 91% water; 7%

proteins and 2% other substances such as ions, nutrients, gases and waste

products. Plasma proteins include albumin (maintains osmotic pressure),

globulins (antibodies and complement which are part of the immune system.

Some globulins are clotting factors which are necessary for the formation of

blood clots.) and fibrinogen (activation of clotting factors results in the

conversion of fibrinogen into fibrin—a threadlike protein that forms blood

clots. Serum is plasma without the clotting factors.

Formed elements consist of red blood cells (RBCs) or erythrocytes

(about 95%), the remaining 5% of the volume of the formed elements

consists of white blood cells (WBCs) or leukocytes and cell fragments called

platelets or thrombocytes. Red blood cells are 700 times more numerous

than white blood cells and 17 times more numerous than platelets.

Production of Formed Elements

The process of blood cell productiion is called hematopoiesis. In

fetus, hematopoiesis occurs in several tissues such as the liver, thymus

gland, spleen, lymph nodes, snd red bone marrow, but some white

blood cells are produced in the lymphatic tissues. All formed elements

of blood are derived from a single population of cells called stem cells

or hemocytoblasts. These stem cells differentiate to give rise to

different cell lines, each of which ends with the formation of particular

type of formed element. The development of each cell line is regulated

by specific growth factor. That is, the type of formed elements are

produced are determined by the growth factors.

Red Blood Cells or Erythrocytes

Normal RBCs are disk-shaped cells with edges that are thicker

than the center of the cell. The biconcave shape increases the surface

area of the red blood cell compared with a flat disck of the same size.

The greater surface area makes it easier for gases to move into and

out of the RBC. In addition, the RBC can bend or fold around its thin

center, decreasing its size and enabling it to pass more easily through

small blood vessels. The main component of the RBC is the pigmented

protein hemoglobin which accounts for about a third of the cell's

volume and is responsible for its color. RBCs transport oxygen from the

lungs to the various tissues of the body and to assist in the transport of

carbon dioxide from the tissues to the lungs.

White Blood Cells or Leukocytes

WBCs are spherical cells that lack hemoglobin. They are larger

than the RBCs and each has a nucleus. Although white blood cells are

components of the blood, the blood serves primarily as a means to

transport these cells to other tissues of the body. Two functions of the

white blood cells are 1. to protect the body against invading

microorganisms and 2. to remove dead cells an debris from the tissues

by phagocytosis. There are two types of WBCs the granulocytes which

contains cytoplasmic granules and there are three types of

granulocytes: a.) neutrophils are small phagocytic cells b.) basophils

promote inflammation and c.) eosinophils that reduce inflammation.

The other types of WBC are the agranulocytes that have very small

granules on which there are two types: a.) lymphocytes are involved in

the antibody production and other immune system respomses; b.)

monocytes become macrophages that ingest microorganisms and

cellular debris.

Platelets or Thrombocytes

Platelets are the minute fragments

of the cells, each consisting of a

small amount of cytoplasm

surrounded by a cell membrane.

They are produced in the red bone

marrow from megakaryocytes which are large cells. Small fragments of

these cells break off and enter the blood as platelets, which play an

important role in preventing blood loss. This prevention is

accomplished in two ways: 1. The formation of the platelet plugs which

seal holes in small vessels, and 2. The formation of clots, which help

seal off larger wounds in the vessels.

Platelet Plug is an accumulation of platelets that can seal up a

small break in a blood vessel. Platelet plug formation is very important

in maintaining the integrity of the circulatory system because small

tears can occur in the smaller vessels and capillaries many times each

day, and platelet plug formation quickly closes them. People who lack

the normal number of platelets tend to develop numerous small

haemorrhages in their skin and internal organs.

The formation of a platelet plug

can be described as a series of steps, but

in actuality many of these steps occur at

the same time. (figure) Platelet adhesion

results in platelets sticking to collagen

exposed by blood vessel damage. Most

platelet adhesion is mediated through

von Willebrand factor, which is a protein

produced and secreted by blood vessel endothelial cells. Von

Willebrand factors forms a bridge between collagen and platelets by

binding to platelet surface receptors and collagen. After platelets

adhere to collagen, they become activated, change shape, and release

chemicals. In the platelet release reaction, platelets release chemicals

such as ADP and thromboxane. ADP and thromboxane binds to their

respective receptors on the surfaces of platelets, resulting in the

activation of the platelets. These activated platelets also releases ADP

and thromboxanes, which activates more platelets. Thus, a cascade of

chemical release activates more platelets. As platelets become

activated they express surface receptors called fibrinogen receptors,

which can bind to fibrinogen, a plasma protein. In platelet aggregation,

fibrinogen forms bridges between the fibrinogen receptors of

numerous platelets resulting in the formation of platelet plug.

Blood Clotting

Blood vessel constriction and platelet plugs alone are not

sufficient to close large tears or cuts in blood vessels. When a blood

vessel is severely damaged, blood clotting or coagulation results in the

formation of a clot. A clot is a network of threadlike protein fibers,

called fibrin that traps blood cells, platelets, and fluid.

The formation of a blood clot depends in a number of proteins

found within the plasma called clotting factors. Normally the clotting

factors are inactive and do not cause clotting. Following injury,

however, the clotting factors are activated to produce a clot. This is a

complex process involving many chemical reactions, but can be

summarized in three main stages:

1. The chemical reactions can be started in two ways:

a.) The contact of inactive clotting factors with exposed

connective tissue can result in their activation; b.)

chemicals such as thromboplastin, released from injured

tissues can cause activation of clotting factors. After the

initial clotting factors are activated, they in turn activate

other clotting factors. A series of reactions results in

which each clotting factor activates the next in the series

until the clotting factor prothrombinase is formed.

2. Prothrombinase acts on an inactive clotting factor called

prothrombin to convert it to its active form called thrombin.

Thrombin converts the inactive clotting factor fibrinogen into its

active form fibrin, a threadlike protein. A clot is a network of fibrin that

traps blood cells, platelets and fluids. At each step of the clotting

process, each clotting factors activates many additional clotting

factors. Consequently, a large quantity of clotting factor is activated,

resulting in the formation of a clot.

Most clotting factors are manufactured in the liver and many of

them require vitamin K for their synthesis. In addition, many of the

chemical reactions of clot formation require Ca2+ and the chemicals

released from platelets. Low levels of vitamin K, low levels of Ca2+,

low numbers of platelets, or reduced synthesis of clotting factors

because of liver dysfunvtion can seriously impair the blood-clotting

process.

Control of Clot Formation

Without control, clotting would spread from the point of its

initiation throughout the entire circulatory system. The blood contains

several anticoagulants, which prevent clotting factors from forming

clots. Anithrombin and heparin, for example, inactivate thrombin.

Without thrombin, fibrinogen is not converted to fibrin, and no clot

forms. Normally there are enough anticoagulants in the blood to

prevent clot formation. At an injury site, however, the activation of

clotting factor is very rapid. Enough clotting factors are activated so

that the anticoagulants can no longer prevent a clot from forming.

Away from the injury site there are enough anticoagulants to prevent

clot formation from spreading.

THE PATIENT’S ILLNESS (Book-Based)

A. Synthesis of the Disease

1. Definition of the Disease

Dengue fever is a type of arbovirus, short for arthropod-borne

virus, caused by one of the four closely related virus serotypes of the

genus Flavavirus—the dengue virus.The v irus that causes dengue fever

is carried by Aedes aegypti mosquitoes, and is transmitted to humans

through their bite. An organism that carries a disease, without actually

developing the disease, is called a vector. It is also called as break

bone or dandy fever because of the bone/ joint pain and the way the

patient seems to be walking on his toes as joint pain affects the client's

toes.

The dengue virus causes the blood vessels to swell and leak,

creating small purple colored spots on the skin, called petechiae. The

skin may appear bruised in areas where the bleeding is worse.

Bleeding into the stomach causes severe abdominal pains and

vomiting of a black, grainy substance that looks like coffee grounds.

This severe bleeding, called hemorrhaging, occurs when the blood runs

out of clotting factors. The damaged blood vessels eventually become

so large that they are unable to supply the needed blood flow and the

oxygen it carries to the body's tissues. This causes the body to go into

shock, and can damage major organs such as the heart and kidneys.

Severe cases of dengue fever are called dengue hemorrhagic fever

(DHF) or dengue shock syndrome (DSS).

The body produces antibodies, which are disease-fighting cells,

that protect the patient who has had dengue fever from being

reinfected for around one year. However, more severe cases of dengue

fever often occur in patients who have already had the virus, then are

reinfected at a later time. Because the immune system recognizes the

virus, it overreacts, causing more severe symptoms. Most people who

have had dengue fever are more likely to have recurring similar viral

infections over the years.

Aedes Aegypti a.k.a tiger mosquito, a common household

mosquito, has the following characteristics, which can be better

remembered through the acronym DLSU: D-day bitting (2 hrs after

sunrise and 2 hrs before sunset), L-low flying, S-stagnant but clear

water and U-urban areas. Only female aedes aegypti mosquitoes which

have gray wings and white stripes are capable of bitting and

transmitting the virus. Susceptibility and risk factors to this virus are

very much important to know because these can alert us if we are at

risk of acquiring the virus. Some of which are: all persons are

susceptible, both sexes are equally affected, age group predominantly

affected are the preschool and school age peak age affectected 4-9

years old, more prevalent in urban communities and frequent in rainy

season. Hygiene and cleanliness in the environment are one of the

strongest defense that we can do against dengue.

2. Predisposing/Precipitating Factors

A. MODIFIABLE FACTORS

1. Environmental

Environmental factors such as artificial containers commonly

found in and around homes. Containers used for storage of water are

important in the increasing in population of mosquitoes in close

proximity to human dwellings. The vector is usually prevalent in urban

and suburban areas. In case of the patient lives in urban and suburban

areas there is a increase in possibility of acquiring the virus infection.

2. Lifestyle

One of the factors is increased in air travel, which is an ideal

mechanism of transferring the virus between population centers of the

world. Those people who acquire the disease are those travelers

visiting tropical areas. They become ill when they return home, which

is resulting in constant movement of dengue viruses.

The female Aedes Aegypti usually bites during daytime, with

limited flying movements, breeds in clear stagnant water and

prevalent in urban and suburban areas. The patient usually plays

during daytime making him to be exposed with the virus and become

infected.

3. Socio- Economic Status

The low socio economic status plays a role in health- wellness

because this affects the family’s ability to give nutritious foods to every

member of the family. There is somehow relation in taking nutritious

feed and immune system since taking these foods strengthens the

immune system.

B. NON MODIFIABLE

1. Age

Worldwide, children younger than 15 years of age are the ones

commonly affected by the dengue virus.

2. Race

Even the race is not specific, the disease’s distribution is

determined geographically. There were fewer cases being reported in

black population than in other races. Most cases of dengue introduced

into United States came from American and Asian tropics, reflecting

the increased in number of persons travelling to and from those areas.

3. Sex

There is no predilection known. But there were fewer cases of

DHF that has been reported in men.

4. Season

Aedes Aegypti is commonly found in tropical and subtropical

countries. Philippines is a tropical country which has 3 major season:

cold (December to February), summer (March-May), and rainy season

(June to November). During rainy season the prevalence of DHF is high

due to accumulated rainwater that increases for mosquitoes’ breeding

places. The patient was diagnosed with DHF on the month of October

on which reported cases of DHF were extensive.

Signs and Symptoms With Rationale

Grade 1

1. Fever

Fever is normal response of the body towards an invading

microorganism (dengue virus). It results from the irritation of the

hypothalamus by chemical mediators (pyrogens and prostaglandin)

causing increased thermoregulatory set point in the hypothalamus.

2. Body pains

Body pain like epigastric pain and joint pain is cause by the

release of chemical mediator prostaglandin that causes the irritation of

the nociceptors causing pain perception.

3. Malaise

Since fever increases the body temperature and basal

metabolism, the body tends to utilize more energy to meet the

increased metabolic rate thus using the reserved or stored energy

resulting in body weakness

4. Anorexia

It has a relationship between malaise, which causes inadequate

food intake. It is also brought about by the alteration in taste sensation

that leads to decrease in appetite.

5. Nausea and Vomiting

This is due to the irritation of the medulla oblongata, which is the

vomiting center of the body.

6. Thrombocytopenia

Dengue virus adheres to the platelet surface, which then

damages it. Platelets becomes injured and removed by the

reticuloendothelial cells of the spleen. Platelet destruction is greater

that platelet production hence reducing the circulating thrombocytes.

7. Petechiae Rash

The rashes appear after the Tourniquet Test in early stage of

dengue. This results from decreased circulating platelet cells and

increased capillary fragility.

Grade 2

1. Spontaneous Bleeding

The bleeding such as purpuric lesions, epistaxis, gum bleeding ,

GI bleeding, etc. results from the decrease circulating thrombocytes,

that enables the body to stop minute capillary bleeding causing

spontaneous bleeding.

Grade 3

1. Hemoconcentration

This is brought about by the increased capillary permeability that

allows some substances ( e.g plasma) to seep out of the capillary and

goes to the interstitial spaces. This results in decreased blood plasma

hence decreasing the circulating blood volume.

2. Cold and Clammy Skin

As a compensatory mechanism of the body in circulating the

volume of blood, peripheral blood vessels constrict to divert more

blood to the vital organs for perfusion. This condition may cause a

decrease surface temperature that results in cold clammy skin.

3. Decrease Blood Pressure

Plasma is the one of the main components of the blood. Plasma

leakage tends to decrease circulating blood volume. The blood volume

is directly proportion to the blood pressure thus as the blood volume

decreases, the blood pressure as well.

4. Rapid and weak pulse

This condition is the body’s compensatory mechanism. Because

blood volume declines, this means that the circulation is also

decreased. In Order to deliver adequate nutrients, oxygen and remove

waste product, especially to the vital organs, the heart will pump

harder and faster but with less stroke volume, which result in rapid

weak pulse.

5. Mental Confusion

Mental confusion is on the latter part of DHF 3 that precedes

shock. This results from decreased cerebral perfusion that causes the

alteration in perception, which is manifested by lethargy at first and

then restlessness.

Grade 4

1. Shock

Is the most critical stage of DHF. This is the end result of severe

plasma leakage, decreased circulating blood and decreased blood

pressure.

Health Promotion and Preventive Aspects of the Disease

Dengue fever, like other arbovirus infections, must run its

course. Treatment is focused on medications to lower fever and reduce

pain, fluids to prevent dehydration, and bed rest. Blood transfusions

are given in cases of severe blood loss, and oxygen must be given to

patients with dengue shock syndrome (DSS). Almost all patients with

dengue fever have a complete recovery. Those with DSS have a good

prognosis if they receive immediate medical treatment.

Supportive and Symptomatic treatment should be provided

for fever, give paracetamol to muscle pains. For headache, give

analgesic. DON"T give ASPIRIN.

Rapid replacement of body fluids is the most important treatmet

Includes intensive monitoring and follow-up

Give ORESOL to replace fluid as in moderate dehydration at 75

mlk/kg in 4-6 hours or up to 2-3L in adults. Continue ORESOL

intake until patient's condition improves.

How to prepare ORESOL

For 1 liter of water

▪ 1 liter pre-boiled waterborne

▪ 8 tsp sugar

▪ 1 tsp salt

▪ 1tsp baking soda

For 1 glass

▪ 240ml/1cup preboiled water

▪ 2 tsp sugar

▪ ¼ tsp sugar

▪ ¼ baking soda

>mix ingredients but remember to make a new one after 24 hours

Methods of prevention and control

Cover water drums and water pails at all times to prevent mosquitoes

from breeding.

Replace water in flower vases once a week.

Clean all water containers once a week. Scrub the sides well to remove

eggs of mosquitoes sticking to the sides.

Clean gutters of leaves and debris so that rain water will not collect as

breeding places of mosquitoes.

Old tires used as roof support should be punctured or cut to avoid

accumulation of water.

Collect and dispose all unusable tin cans, jars, bottles and other items

that can collect and hold water.

Fumigation would only drive away mosquitoes but would not clean the

breeding grounds so it's not a good and effective way of preventing

dengue.

1. Eliminate vector by:

a. Changing water and scrubbing sides of lower vases once a week.

b. Destroy breeding places of mosquito by cleaning surroundings.

c. Proper disposal of rubber tires, empty bottles and cans.

d. Keep water containers covered.

2. Avoid too many hanging clothes inside the house.

3. Residual spraying with insecticides.

Prevention of Mosquito Bites

Use mosquito nets during nights -mosquito nets with permethrine

solution are better.

Wear bright and light color clothing, as mosquitoes are attracted to

dark clothing.

Wear long sleeved clothes and long pants.

Wear boots and socks and if necessary tuck the pants into the socks

Avoid outdoor activities during dawn or dusk when these mosquitoes

are most active

Avoid strong perfumes as they attract mosquitoes.

Use mosquito repellent spray or lotion.

THE PATIENT’S ILLNESS (Patient-Based)

Non-Modifiable risk factors

1. Antibody for dengue virus

DHF may be caused by the four closely related virus

serotypes. The patient did not experience to have dengue infection

before. This made him susceptible to dengue infection since his body

has not yet developed antibody against strains of dengue virus. Since

being infected to one virus of serotypes of dengue make immunity to

that serotype for life, the patient can have more than one dengue

infection.

2. Age

DHF may inflict people from all age groups, though it is more

common among children.

3. Sex

There is no preference known. DHF inflicts both male and

female. The patient is male.

4. Season

The patient lives in the Philippines which is a tropical country.

This characteristic contributes to the incidence of DHF especially

during the rainy season when rainwater easily accumulates in

particular areas which makes for good breeding places for mosquitoes.

Modifiable Risk Factors

1.Lifestyle

The patient went swimming with his family at a public pool.

He spent the whole day swimming and having fun. The next day, he

developed fever which was the beginning of his DHF. His mother also

mentioned that the pool was surrounded by plants which contributed

to the presence of mosquitoes.

Signs and Symptoms

The patient manifested the following:

Grade 1

• Fever, abdominal pain, and weakness

These are attributed to the release of prostaglandin and other cell

injury/ inflammatory mediators secondary to the release of viral

anaphylatoxins.

• Abnormal WBC count

The presence of inflammation and cell injury leads to abnormal

test result. The presence of virus triggered the stimulation of body’s

defense mechanism which includes the release of WBC component of

the blood.

• Petechiae

The client had reddish rashes on his lower extremities,

specifically his legs. This is related to the presence of weak capillaries

secondary to the activation of kinins which affect the vascular

permeability. Capillaries are fragile blood vessels. Increase in vascular

permeability causes increased pressure towards the capillary.

Grade 2

The patient manifested bleeding, specifically epistaxis.

*The patient did not manifest grade 3 and 4 DHF*