PLATELET & COAGULATION DISORDERS

RAFEAH RUSLI 03-200904-00277RAFIDAH ABRAHAM 03-200904-00324RANDY B. GUBUD 03-200904-00264SANDRA LOUIS 03-200904-00274SARTIKA AMRAN 03-200904-00180VERA DIANE 03-200904-00244

Presenting…

Objective:

Describe platelet List the types of platelet &

coagulation disorder Describe briefly about the disorders Laboratory diagnosis

Platelet Platelets are produced in blood cell formation

(thrombopoiesis) in bone marrow megakaryoblast > pro-megakaryocyte > immature

megakaryocyte > megakaryocyte > Platelet Platelets or thrombocytes are small irregularly shaped non-nucleated 2–3 µm in diameter. lifespan of circulating platelets is 5 to 9 days. platelet production is regulated by thrombopoietin

(hormone which produced by the liver and kidneys) Old platelets are destroyed by phagocytosis in the

spleen and by Kupffer cells in the liver

Platelet formation:

Platelet cont… The platelet structure has 3 zones:

Peripheral Structural Organelle

Structural zone Consists of the cytoskeleton The cytoskeleton forms the support for the maintenance of the

platelet’s discoid shape Regulate contractile system that allows, upon activation, shape

change, pseudopod extension, internal contraction, and release of granular constituents.

Resting platelets

Activated platelets

Platelet

Platelet cont…

Organelle zone consists of the granules and cellular components These organelles serve in the metabolic processes of the platelet and

store enzymes. dense granules contain non-metabolic adenosine triphosphate (ATP)

and adenosine diphosphate (ADP), serotonin, and calcium alpha granules contain adhesive proteins such as fibrinogen,

fibronectin, von Willebrand factor (VWF), thrombospondin, and vitronectin.

alpha granules also contain growth-promoting substances such as platelet-derived growth factor (PDGF), platelet factor 4, and transforming growth factor.

Coagulation factors including factor V, high molecular weight kininogen, factor XI, and plasminogen activator inhibitor-1 are also present in the alpha granule.

Platelet cont…

Membrane / peripheral zone Consist of typical phospholipid bilayer membrane Embedded in this structure are different kind of glycoprotein.

Glcoprotein Function

GP IIb/IIIa Receptor for fibrinogen, VWF, fibronectin, vitronectin and ThrombospondinFor platelet aggregation

GP Ia/IIa Receptor for Collage

GP Ib/IX/V Receptor for insoluble VWFor platelet adhesion

GP VI Receptor for Collagen

General function of platelet The function of platelets is the maintenance of hemostasis. Platelets helps in blood clotting. Wound repair Platelets secrete platelet-derived growth factor (PDGF). Granule secretion. Adhesion and aggregation. Pro-coagulation. Cytokine signalling. Phagocytosis. Transport of enzyme and proteins critical to clotting. Formation of a platelet plug to slow blood loss. Contraction of a clot after it has formed, which then reduces

the size of the vessel break.

platelet ultrastructure…..

Alpha granules Dense bodies

VwF ADP

Fibronectin ATP

Thrombospondin Serotin

Types of disorder:

Divided into: Coagulation disorder Platelets disorder

Coagulation disorder include: Henophilia Von Willebrand disease

Platelet disorder include: Deficiency Of Vitamin K. Bernard - Soulier Syndrome. Thrombasthenia Of Glanzmann And Naegeli (Glanzmann

Thrombasthenia) Gray Platelet Syndrome. Dense Granule Deficiency Syndrome. Thrombotic Thrombocytopenic Purpura (TTP). Idiopathic Thrombocytopenic Purpura (ITP).

Hemophilia Definition: disease associated with prolonged bleeding

due to the deficiency in clotting factor. Hemophilia is a X-linked disease Types of Hemophilia:

Hemophilia A Factor 8 deficiency, x linked disease

Hemophilia B Factor 9 deficiency, x-linked disease

Hemophilia C Factor 11 deficiency, autosomal genetic disorder

Symptoms of hemophilia: Bruising Bleeds easily Bleeding into a joint Bleeding into the muscles Bleeding from injury or bleeding in the brain Other sources of bleeding (eg. Stool & urine)

Von Willebrand disease

The most common hereditary coagulation abnormality Can also be acquired as a result of other medical conditions Due to the deficiency of von Willebrand factor (vWF) Von Willebrand factor - mediates binding of glycoprotein Ib

to collagen This binding mediate activation of platelets and formation of

primary hemostasis Defect in this factor, resulting glycoprotein IB does not bind

to collagen. Thus unable to activate platelets, primary hemostasis does

not occur

Lab findings: comparison between Hemophilia A, Hemophilia B & von Willebrand disease

Symptoms of von Willebrand disease: Abnormal menstrual bleeding Bleeding of the gums Bruising Nosebleeds Skin rash

Condition PT APTT Bleeding time

Hemophilia A Normal Increased Normal

Hemophilia B Normal Increased normal

Von Willebrand disease

Normal Increased increased

Bernard-Soulier syndrome

Also known as hemorrhagiparous thrombocytic dystrophy It is due to deficiency of glycoprotein Ib (GPIb), the receptor

for von willebrand factor Lacks of GPIb cause vWF unable to bind to the glycoprotein finally lead to decrease in primary clot formation / primary

hemostasis Characterized by

Characterized by abnormally large platelets / giant platelets Characterized by prolonged bleeding time, thrombocytopenia, increased

megakaryocytes, and decreased platelet survival

Some of the symptoms: Purpura. Epistaxis. Menorrhagia. Gingival and gastrointestinal bleeding.

Deficiency of Vitamin K Role of Vitamin K in blood coagulation:

Important in maturation of clotting factor. modification of certain proteins required for blood coagulation

If the clotting factor does not mature, it is useless in the hemostasis process.

Factor which causes the deficiency of vitamin K Disturbed intestinal uptake. By therapeutic or accidental intake of vitamin k-antagonists or

very rarely. By nutritional vitamin k deficiency

Some of the possible symptoms of vitamin K deficiency: Risk of massive uncontrolled bleeding Hematomas

THROMBASTHENIA OF GLANZMANN AND NAEGELI extremely rare coagulopathy can be inherited in an autosomal recessive manner or

acquired as an autoimmune disorder due to deficiency in glycoprotein IIb/IIIa (GpIIb/IIIa) glycoprotein IIb/IIIa (GpIIb/IIIa) is receptor for

fibrinogen. When glycoprotein IIb/IIIa (GpIIb/IIIa) receptor is

dysfunction, fibrinogen cannot bind to the platelets. As a result, no fibrinogen bridging of platelets to other

platelets occur In other words, primary hemostasis inhibited and

prevent platelets aggregation Bleeding time is significantly prolonged

THROMBASTHENIA OF GLANZMANN AND NAEGELI

Symptoms includes:

Increased mucosal bleeding.

Epistaxis.

Menorrhagia.

Increased bleeding post-operatively.

The bleeding tendency is variable but may be severe.

Platelet numbers and morphology are normal.

Platelet aggregation is normal with ristocetin, but impaired with

other agonists such as ADP, thrombin, collagen or epinephrine.

GRAY PLATELET SYNDROME

Gray platelet syndrome (GPS) is a rare inherited bleeding disorder.

The abnormal alpha-granules appear grey on blood films stained by the May-Grünwald-Giesma stain - hence, the syndrome's name.

It caused by the inability of platelets to store alpha-granule proteins.

The platelets' haemostatic proteins are not released at the site of vascular injury.

Thus slows aggregation and vessel repair And contribute to the bleeding tendency. Symptoms may include:

platelets that have a gray appearance severe thrombocytopenia myelofibrosis splenomegaly

DENSE GRANULE DEFICIENCY SYNDROME

it is a bleeding disorder caused by a deficiency in dense granules in the platelets

Dense granules release chemicals in the clotting process and help platelets stick together to form clots.

Lacks of dense granules in platelets means lacks of storage sites for substances for clotting.

Therefore no chemicals which facilitates in the clotting process will be released.

Finally leads to slow platelet activation, and prolonged bleding.

THROMBOTIC THROMBOCYTOPENIC PURPURA (TTP) A blood disorder that causes blood clots to form in small blood

vessels around the body, and leads to a low platelet count. The two main types of TTP are inherited and acquired. In inherited TTP, the ADAMTS13 gene is faulty and doesn't

prompt the body to make a normal ADAMTS13 enzyme. As a result, enzyme activity is lacking or changed.

Acquired TTP is the more common type of the disorder. The ADAMTS13 gene isn't faulty. Instead, the body makes antibodies (proteins) that block the activity of the ADAMTS13 enzyme.

A lack of activity in the ADAMTS13 enzyme causes TTP. The ADAMTS13 gene controls the enzyme, which is involved

in blood clotting. The enzyme breaks up a large protein called von Willebrand

factor that clumps together with platelets to form blood clots.

IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP) Also known as immune thrombocytopenic purpura, is

classified as an autoimmune disease. The term “idiopathic” indicates that the disease is of an

unknown cause or origin: in other words, modern medicine has not yet figured out what it is. 

And the word “purpura” comes from a description of the bruise-colored skin of someone afflicted with the disease: the purple color caused by blood that leaked under the skin.

IDIOPATHIC THROMBOCYTOPENIC PURPURA (ITP) Idiopathic thrombocytopenic purpura is a bleeding disorder

in which the immune system destroys platelets Persons with the disease have too few platelets in the blood The two types of ITP are acute (temporary or short-term)

and chronic (long-lasting). Acute ITP generally lasts less than 6 months. It mainly occurs in children

—both boys and girls—and is the most common type of ITP. Acute ITP often occurs after a viral infection.

Chronic ITP lasts 6 months or longer and mostly affects adults. However, some teenagers and children do get this type of ITP. Chronic ITP affects women two to three times more often than men.

Symptoms: Abnormally heavy menstruation. Bleeding into the skin causes a characteristic skin rash that looks like

pinpoint red spots. (petechial rash) Easy bruising. Nosebleed or bleeding in the mouth.

Lab diagnosis

Status of platelet & coagulation process can be screened by using the following simple lab test: Bleeding Time Clotting time Activated partial thromboplastin time (APTT) Prothrombin time (PT) Full Blood Count Peripheral Blood Film May-Grünwald-Giesma stain

Bleeding time

Function: Basic screening test of platelet function

Procedure: Place a blood pressure cuff on the arm and inflare it to 40mm Hg Clean the area of the fore arm below the anticubital fossa with 70%

alcohol. There should be no superficial veins in the area selected Make 2 skin punctures in rapid succession, each 3mm deep, by using

disposable lancets Start the stop-watch as soon as bleeding starts. Wipe off the blood at 15

seconds interval by touching lightly with a blotting paper Record the time taken for the blood to stop flowing in the both

punctures and determine the mean time. Remove the blood pressure cuff and cover the puncture site with plaster

Result: Normal range : 2-6 minutes Borderline : 6-10 minutes (Test should be

repeated)

Bleeding time:

Clotting time: Function:

To measure he time required for a sample of blood to coagulate in vitro under standard conditions

Procedure: Make a clean venipuncture with minimum trauma to the connective

tissue Start stop-watch as soon as the blood enters the glass syringe. Draw 4ml of blood and deliver 1ml each into 4 glass tubes previously

warmed to 37ºC Place the tube immediately at 37ºC water bath At the end of each minutes, gently tilt one tube to see if the blood is clotted. Continue tilting the tube one after the other at one minute interval till one of them can

be tilted at 90º without the blood flowing out. Note the time Continue with the remaining tubes and take the average of the clotting time in all the 4

tubes

Reference values: Normal values : 5-10 minutes Prolonged clotting time is a marked deficiency in one of the coagulation factors of

intrinsic pathway.

Replaced by APTT

Activated partial thromboplastin time

Function: Evaluate intrinsic pathway Measure all coagulating factor except factor VII and XIII Monitor heparin therapy

Procedure: Pre-warmed APTT reagent at 37ºC for at least 10 minutes. Collect blood specimen in blue top tube Centrifuge and separate the plasma from blood Add 100µl of APTT reagent into a test tube, then add 100µl of plasma into the test

tube and incubate for 2-3 minutes Then add 100µl calcium chloride reagent to the plasma Start stop-watch until clot formed Record the time at which clot form

Reference value: Normal range : 35-45 seconds

Prothrombin time Function:

Used to evaluate the extrinsic pathway (factor 1,2,5,7, and 10) Also used to monitor warfarin therapy

Procedure: Collect blood in blue top tube. Centrifuge blood and separate plasma from blood Make sure to pre-warmed PT reagent 37ºC for at least 10 minutes

before use. Place 100µl plasma into test tube. Pre-warm plasma for 2-3 minutes at 37ºC Then add 200µl of PT reagent to the tube, simultaneously start the stop-watch and

record the time required for clot formation.

Reference value: Normal range : 11-14 seconds

Coagulation pathway:

Other lab test: Full blood count:

Normal range : 150,000 – 400,000 /ul Those with coagulation / platelet disorder :

thrombocytopenia

PBF: Giant platelet may present thrombocytopenia

Special staining: MGG stain for Gray platelet syndrome

Thrombocytosis

Giant Platelet Giant Platelet

Thrombocytopenia

End of PresentationThank You!!