Bleeding DIsorders Flashcards by Thea Guillermo

The platelet count will show (qualitative / quatitative) disorder of platelets? What is the normal value?

quantitative; 150,000 - 300,000 platelets/microliter (isnt it supposed to be 450,000???)

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If the platelet count is normal, bleeding time will show (qualitative / quatitative) disorder of platelets?

qualitative

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Abnormal clotting time shows an abnormality in?

Extrinsic, Intrinsic and Common coagulation factors

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Prothrombin time (PT) assesses (intrinsic / extrinsic) pathway in addition to the common pathway? Enumerate factors involved.

Extrinsic factors; F V, VII, X, prothrombin, fibrinogen

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Activated Partial Thromboplastin time (aPTT) assesses (intrinsic / extrinsic) pathway in addition to the common pathway? Enumerate factors involved.

Intrinsic; F V, VIII, IX, X, XI, XII, prothrombin, fibrinogen

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Excessive bleeding can result from?

Increased fragility of vessels, platelet deficiency, derangement of coagulation

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In bleeding diorders with vessel wall abnormality, platelet count, bleeding time, PT, PTT are all (increased/decreased/normal)

NORMAL

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What are the common causes of vessel wall abnormality

Infections, drug reactions, scurvy, Ehler’s Danlos, Henoch-Schonlein purpura, Hereditary hemorrhagic telangectasia (Weber-Osler-Rendu Syndrome), Perivascular amyloidosis

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Describe the vessels in hereditary hemorrhagic telangectasia (Weber-Osler-Rendu Syndrome). Most common sites of bleeding?

Dilated and tortuous with thin walls; mucous membranes of nose, tongue, mouth, eyes, GIT

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What causes Henoch-Schonlein purpura?

deposition of circulating immune complexes within the vessels and glomerular mesangial regions

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At what platelet level is considered thrombocytopenia?

less than 100,000 platelets/microliter

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At what platelet level does spontaneous bleeding become evident?

less than 20,000 platelets/microliter

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What is the most feared (hahaha wtf??) complication of thrombocytopenia?

intracranial bleed

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Platelet levels of 20,000 - 50,000 can aggravate ________ bleeding

post traumatic

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(T/F) You should transfuse a patient (not undergoing surgery) when platelets are <20,000

False, do not transfuse unless symptomatic b/c body might produce antibodies against transfused platelets

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Bleeding from thrombocytopenia is associated with (increased/decreased/normal) PT & PTT and often involves small vessels

Normal

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Causes of thrombocytopenia

Decreased platelet production 
Decreased platelet survival
Sequestration
Massive transfusion / dilution
Ineffective megakaryopoesis

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Heparin causes a _______in platelet count

decrease

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An autoimmune disease producing antibodies against platelets wherein there is a normal bone marrow (or increased megakaryocytes)

Idiopathic Thrombocytopenic Purpura (ITP)

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Differences in population affected between acute and chronic ITP

Acute is self-limited an seen in childrenof any gender 1-2 weeks after a viral infection; Chronic is seen in adults especially in pregnant wormen with autoimmune disorders

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In Chronic ITP, autaoantibodies are directed against platelet membrane glycoprotein of this type

Gp IIb/IIIa or Ib-IX

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What Ig class is usually seen in chronic ITP

IgG

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In chronic ITP, what is the alternative treatment to steroids? How does it help?

splenectomy. Removal of the source of autoantibodies

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(T/F) Platelet concentrate transfusion in patients with ITP is helpful

False. Antibodies will just destroy the platelets

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What is the characteristic pentad of thrombotic thrombocytopenic purpura (TTP)

1) Microangiopathic hemolytic anemia 2) Decreased platelets 3) Fever 4) Transient neurologic defects 5) Renal failure (usually in females, 4th decade of life)

Morphology in TTP

Widespread hyaline microthrombi

What is the enzyme deficiency in TTP?

ADAMTS 13 or vWF metalloprotease

What is the function of the enzyme ADAMTS 13?

degrades vWF

What are the main functions of vWF?

Platelet adhesion | Carry factor VIII and improve its lifespan

What is the treatment for TTP

Plasma exchange

What would be a differential diagnosis for TTP? How do you differentiate?

Hemolytic Uremic Syndrome (HUS). HUS does not have associated neurologic manifestations & ADAMTS 13 levels are normal

What is the etiology of HUS?

Bacterial toxin (EHEC) that stimulate platelet aggregation

What is the cause of typical HUS?

O157:H7 elaborates shiga-like toxin that alters endothelial cell function when absorbed, causing platelet activation and aggregration

What is the cause of atypical HUS?

Defect in complement factor H, CD46 or factor I

Examples of inborn/congenital abnormalities in platelet function

Von WIlldebrand Disease, Bernard soulier Syndrome, Glanzmann Thrombasthenia, Disorders of platelet secretion

Reasons for acquired abnormalities in platelet function

Aspirin or NSAIDS, Uremia

What is the most common inherited bleeding disorder in humans?

Von Willdebrand disease

aPTT & PTT is _____ in Von Willdebrand disease and platelet count is _______; Risotcetin aggregation test is _______

elevated; normal; reduced

What is defective in Von Willdebrand disease

vWF causing defective adhesion

Which types of Von Willdebrand disease are associated with reduced quantity of circulating vWF? Which one autosomal recessive and is associated with extremely low levels of vWF?

Type 1 and 3; Type 3

Type 2 Von Willdebrand disease is characterized by ________ defect in vWF

Qualitative

Type 1 Von Willdebrand disease is autosomal _______?

dominant

In type 2 Von Willdebrand disease, ______ mutations cause defective multimer assembly

missense

In Bernard Soulier Syndrome, defective adhesion is caused by the lack of ______?

GpIb

Lack of GpIIb/IIIa in Glanzmann Thrombasthenia causes defective _______?

aggregation

In acquired platelet abnormalities d/t uremia, the platelet count is ______ and the BT is ______

Normal; Elevated

The complex pathogenesis In acquired platelet abnormalities d/t uremia involves defects in ____, _____ and ______.

aggregation, adhesion and granule secretion

Increased clotting time with normal platelet and BT is indicative of abnormalities in ____?

Clotting factors

Abnormalities in extrinsic pathway factors will show an elevated ______?

Abnormalities in intrinsic pathway factors will show an elevated ______?

PTT

vWF is synthesized in by?

endothelial cells and megakaryocytes

What is the most important function of vWF?

Promote adhesion of platelets to the subendothelial matrix

vWF stabilizes factor ____

VIII

factor VIII is an essential cofactor of factor

What is the most common hereditary disease that is associated with life-threatening bleeding?

Hemophilia A

Hemophilia A is caused by a deficiency in factor ____

VIII

Hemophilia B (aka Christmas disease) is caused by a deficiency in factor ____

Hemophilia ___ is associated with normal PT and prolonged PTT

A and B

(T/F) Both hemophilia A & B are recessive x-linked traits

True

What is required for the diagnosis of hemophilia?

Specific assays of factor levels

Liver disease and Vitamin K deficiency affects the following factors

II, VII, IX, X

Disseminated Intravascular Coagulation (DIC) is caused by

excessive activation of coagulation leading to the consumption of platelets, fibrin and coagulation factors

DIC is not a primary disease, it is caused by complications of conditions such as:

Obstetric complications / difficult labor Neoplasms Infections/sepsis Massive tissue injury

Give some triggers of DIC

Release of tissue factor or thromboplastic substances into circulation and widespread injury to endothelial cells

Widespread injury to endothelial cells can be seen in

Bacterial infections Massive trauma Obstetric conditions Neoplasms

Possible consequences of DIC

WIdespread deposition of fibrin and microangiopathic hemolytic anemia Hemorrhagic diathesis

In DIC, thrombi are usually seen in the

Kidneys, alveolar capillaries, CNS, adrenals, spleen, liver

Waterhouse Friedrichsen Syndrome is d/t

massive adrenal hemorrages

Widespread microthrombi in the placenta causing premature atrophy of the cytotrophoblasts and syncytiotrophoblast

Sheenhan postpartum pituitary necrosis

What is the definitive treatment for DIC?

Removal or treatment of inciting cause

DIC is characterized by

``` microangiopathic hemolytic anemia Dyspnea, cyanosis, renal failure Convulsions, coma Oliguria, acute renal failure Sudden or progressive circulatory failure / shock ```