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Precipitating Factors

Environmental Conditions (Stagnant water as breeding sites)

Sweaty skin

Dengue Carrier Mosquitoes

Predisposing Factors

Geographical AreaBite to skin from dengue carrier mosquito (Itchiness and redness at the bite area)Replication of virus in mosquitos salivary glandsDengue virus is inoculated in the blood with 8-14 days incubation periodrapidly in the blood stimulating WBCs and B lymphocytes and produces antibodies, and macrophages.erforms phagocytosis; dengue virus replicates within the cells; antibodies attach to viral antigensEntry to the bone marrowEntry to the spleenkines and other platelet activating factors that stimulates WBCs and pyrogen release

Dengue

s/s:

High grade fever

Flushed skin

Weakness

Headache

targets the liver and spleen parenchymal cells which causes cell deathection of the red bone marrow which causes immunologically shortened platelet productionHepatosplenomegaly

If untreated:

Complications such as:

Intense bleeding

Severe hypotension

Pulmonary edema

Shock

Liver cirrhosis

Death

e accumulation of fluids in theperitoneal cavity

reated:

dration

reful monitoring ofpatients condition

ug therapy: antipyretics for fever

ly diagnosis

Pleural Effusione of fluid from blood to interstitial fluidn number and size of pores of capillariesDengue Hemorrhagic Fevera insufficient number of circulating plateletsRecoveryAnatomy and Physiology

Blood

Blood is the so called river of life that flows within us. It is responsible of transportation ofeverything that needs to be carried out throughout the body. It transports nutrients, body wastes and body

heat through the blood vessels.

Physical Characteristics

The color of the blood varies depending on the amount of oxygen it carries. It varies from scarlet

(oxygen-rich) to dull red (oxygen-poor). The blood is about five times heavier than water and it is more

viscous because of its formed elements. It is slightly alkaline with a pH between 7.35-7.45. Its

temperature is at 38 C, slightly higher than the body temperature.

Components of blood

The blood is considered to be the only fluid tissue in the body. It is a complex connective tissue in

which formed elements are suspended in a nonliving fluid matrix called the plasma. The plasma is the

liquid part of the blood and is approximately 90% water.

There are 3 formed elements in the blood.

1.) Erythrocytes responsible for blood gas transport

2.) Leukocytes defends body from diseases

3.) Platelets needed for normal blood clotting

(In this case, platelets are the ones mostly affected by the dengue virus so it will be our focus.)

Blood Cell Formation/Hematopoiesis (Platelets)

Hematopoiesis occurs in the red bone marrow or the myeloid tissue. Red bone marrow is found

chiefly in flat bones like the skull and pelvis, the ribs, sternum and proximal epiphyses of humerus and

femur. All of the formed elements arise from a common type of stem cell called hemocytoblast which

resides in the red bone marrow.

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The hemocytoblast stem cells develop into lymphoid or myeloid stem cells. Myeloid stem cells

by then will develop as platelets or other formed elements depending on the response to the changing

body needs and different stimuli. Like the other formed elements in the blood, platelet production is

stimulated by hormones. The hormone thrombopoietin accelerates the production of platelets but only

little is known about how this process is regulated.

Platelets

Platelets are not cells in a strict sense. They are

fragments of bizarre multinucleated cells of megakaryocytes. They appear as darkly stained and

irregularly shaped. The normal platelet count is 150,000-500,000 per cubic millimeter.

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Physiology of Platelets

Platelets are responsible for normal blood clotting. If we are going to live without it, a single cut

would make us bleed to death. There is a process called hemostasis wherein platelets have a major role.

Hemostasis means stoppage of bleeding. It happens when a blood vessel breaks or is injured. Hemostasis

involves three major phases which occur in rapid sequence.

1. Vascular spasms occur the immediate response of the body to blood vessel injury

2. Platelet plug forms when the endothelium is broken, the collagen fibers are exposed that leads

to clinging of the platelets to the damage site and making them sticky. Platelets release chemicals

that attract more platelets to the site of damage.

3. Coagulation events occur

a. Injured tissues release tissue factor(TF), substance that plays an important role in clotting

b. PF3,which is a phospholipid, coats the surfaces of the platelets, interacts with the TF, vitamin

K, calcium ions and other protein clotting factors

c. Prothrombin activator for conversion of prothrombin to thrombin which is an enzyme.

d. Thrombin joins fibrinogen proteins to form long hair like molecules of insoluble fibrin which

forms a netlike meshwork that traps RBCs and forms the basis of the clot.

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Pathophysiology Book-Based

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