Chapter 14; Alterations in Hemostasis and Blood Coagulation

Disseminated Intravascular Coagulation (DIC)

Acquired hemorrhagic syndrome in which clotting and bleeding occur simultaneously Fibrinogen level and platelet count decreased Increased bleeding time Elevated PT/INR/aPTT/D-dimer Treatment: removal/correction of underlying cause

Vascular Disorders

Allergic Purpura- Patients will have itchy skin Scurvy - Vitamin C deficiency

Stages of Hemostasis

Primary hemostasis—initial response to vascular injury involving the interaction between platelets and the endothelium of the injured vessel Injured vessel vasoconstricts to prevent blood loss Formation of a platelet plug Secondary hemostasis involves the formation of a fibrin clot through intrinsic and extrinsic pathways

Vascular and Platelet Disorders

Primary cause of bleeding is a problem with the vascular component of primary hemostasis ***May be acquired or inherited***

Platelet Disorders

Primary cause of bleeding is an abnormality in the quantity or quality of platelets May be acquired or inherited

Von Willebrand Disease Hallmark

***Epistaxis***

Qualitative Platelet Disorders

Ability of platelets to function in the hemostatic process is abnormal Inherited disorders include Bernard-Soulier syndrome, von Willebrand disease, and thrombasthenia Acquired disorders more common (drug-induced, renal failure, hematologic disease) Treatment based on underlying disorder and may require platelet transfusion

Vascular and Platelet Disorders; Vascular Disorders

Abnormality of the vessels or tissues Purpura (patches of petechiae) are present Allergic purpura: autoimmune process Ehlers-Danlos syndrome: deficient collagen and elastin Vitamin C deficiency: defective collagen synthesis Aging: loss of subcutaneous fat and changes in connective tissue

What are the common causes of platelet deficiencies, excesses, and dysfunction?

An insufficient quantity of platelets results from decreased production, sequestration, increased destruction, or dilution. Important causes of thrombocytopenia include autoimmune destruction, idiopathic thrombocytopenic purpura (ITP), disseminated intravascular coagulation (DIC), and mechanical destruction (of artificial valves). Excessive quantity of platelets results from excessive production due to proliferation of bone marrow cells. Platelet dysfunction may include abnormal platelet adhesion, aggregation and degranulation, resulting in prolonged bleeding time. The usual cause of platelet dysfunction is drug related (pgs. 302-304).

Von Willebrand Disease

Autosomal dominant disorder of factor VIII carrier protein and platelet dysfunction Causes excessive bleeding Treatment with desmopressin, which releases von Willebrand factor and factor VII from vascular endothelial cells; cryoprecipitate and humate-P used to manage severe bleeding

Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Disease)

Autosomal dominant trait Vessel wall composed of single layer of endothelium Multiple telangiectases, repeated episodes of bleeding, or a family history in both sexes Supportive tx with topical hemostatic agents, cauterization, iron replacement, laser therapy

Qualitative Platelet Disorders; Hallmark

Bernard-Soulier syndrome- (Giant platelet syndrome) Hallmark --- Pts will have excessive bleeding before and after therapy

Tourniquet Test-

Blood pressure cuff test for Vascular Purpura (Look Up)

Disseminated Intravascular Coagulation (DIC)

Body hemorrhages and clots at the same time Hemorrhage happens 1st Read and study (Memorize the Process)

Hepatic Disease

Coagulopathies result from: -Impaired absorption of vitamin K -Decreased synthesis of fibrinogen, factors V and XI -Inability to remove activated coagulation factors and fibrinolytic proteins from circulation -Altered production of inhibitors of coagulation Treatment includes vitamin K administration; transfusion of platelets, fresh frozen plasma, or whole blood

What are the common causes of inherited and acquired disorders of coagulation?

Common causes of inherited disorders of coagulation include hemophilia and von Willebrand disease. Common acquired disorders include vitamin K deficiency DIC, and hepatic disease (pgs. 304-307).

Evaluation of primary and secondary hemostasis

CBC is 1st thing; check for anemia Know bleed time And lab values

Coagulation Disorders

Coagulopathies are defects of the normal clotting mechanism Results can include: Bleeding from a problem with the formation, stabilization or lysis of the fibrin clot Excessive clot formation due to inappropriate activation of the coagulation cascade

A general mechanism noted in thrombocytopenia is which of the following?

Decreased platelet survival Splenic sequestration In thrombocytopenia, four mechanisms are involved, including the decreased production of platelets, the decreased survival of platelets, the sequestration (pooling) of platelets in the spleen, and intravascular dilution. Hemorrhage is not one of the mechanisms involved in thrombocytopenia

Vitamin K Deficiency Bleeding in Infancy

Deficiency of vitamin K-dependent coagulation factors (II, VII, IX, and X) Evidence of bleeding occurs early in life (melena, hematuria, intracranial hemorrhage, hypovolemic shock) Prophylactic administration of vitamin K to the newborn largely eliminates this coagulation disorder

Vascular Purpura

Diagnosis is one of exclusion after platelet and coagulation disorders are ruled out Tourniquet (Rumpel-Leede) test may be used Treatment is geared toward removing and avoiding the causative agent

What vascular alterations result in abnormalities of hemostasis?

Disorders of the vasculature that result in altered hemostasis include inflammation (allergic purpura), structural abnormalities (collagen diseases), and weakened vessel walls (telangiectasia) (pgs. 301-302).

Von Willebrand disease may present itself by which of the following?

Epistaxis Epistaxis and ecchymoses are common clinical manifestations of von Willebrand disease, and the level of von Willebrand factor is decreased or absent. In von Willebrand disease, the platelet count and PT are normal, but aPTT is prolonged

Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Disease) Hallmark

Epistaxis-nosebleeds (reoccurring nosebleeds) ***Halmark*** Will bleeding in lips and tounge

Laboratory Tests

Evaluation of primary and secondary hemostasis -CBC to identify anemia -Platelet count to identify number of platelets Peripheral smear indicates the number and gross morphologic characteristics of platelet function -Bleeding time evaluates vascular status and platelet function -PT/INR assesses the extrinsic pathway of coagulation -aPTT assesses the intrinsic pathway

How do platelets and factors of the clotting cascade contribute to hemostasis?

Factors released from platelets contribute to hemostasis by enhancing vasoconstriction, platelet aggregation, and vessel repair. Activation of the clotting cascade results in a fibrin clot (pgs. 294-297).

Characteristics of allergic purpura lesions include which of the following?

Fever and itching Purpura lesions are itchy and a fever is likely. They are raised and are usually easily felt. Bleeding from the lesions themselves and generalized bleeding are uncommon. The lesions tend to be found on the proximal extremities, especially on the legs and buttocks. The lesions tend to be found on the proximal extremities, especially on the legs and buttocks.

Petechiae that are a result of vascular and platelet disorders are noted to be which of the following?

Flat Pinpoint Nonblanching Petechiae are caused by capillary hemorrhages in the skin and mucous membranes, so they are small, flat, and nonblanching. Petechiae are caused by capillary hemorrhages in the skin and mucous membranes, so they are not scaly or fluid-filled

Thrombocytopenia

General mechanisms Decreased platelet production Decreased platelet survival Splenic sequestration Intravascular dilution of circulating platelets Low platelet count, prolonged bleeding time, abnormal peripheral smear Treatment based on identified cause

Hemophilia Halmark

Hallmark*** Hemarthrosis*** Cryoprecipitate- freeze plasma

Hemophilia

Hemophilia The most common inherited coagulation disorder resulting in excessive bleeding Hemophilia A—factor VIII deficiency Hemophilia B—factor IX deficiency Treatment includes patient/family education Hemophilia A: cryoprecipitate or factor VIII concentrate Hemophilia B: fresh frozen plasma or cryoprecipitate Hallmark*** Hemarthrosis*** Cryoprecipitate- freeze plasma

The Process of Hemostasis

Hemostasis is the arrest of bleeding or prevention of blood loss after blood vessel injury Involves the vessel wall, circulating platelets, and plasma coagulation proteins

Evaluation of Hemostasis and Coagulation

Included in patient history and physical exam Determine if problem exists and underlying cause so appropriate management is initiated Especially indicated for: Personal/family history of bleeding disorder During active bleeding that is unresponsive to standard interventions Screening before surgery Ongoing evaluation of anticoagulation therapy

Thrombocytosis description

Increase in platelets due to clotting (know clinical reference guide) polycythemia vera - bone marrow make too many blood cells

Fibrin Clot

Intrinsic pathway initiated when blood comes into contact with altered vascular endothelium Extrinsic pathway begins when the vascular wall is traumatized (crush injury)

Which statement is true about disseminated intravascular coagulation (DIC)?

It is both a bleeding and clotting disorder DIC is both a bleeding and clotting disorder. There are two types, with the chronic type being more prone to thrombotic episodes because the liver and bone marrow are functioning at a higher level and are able to produce more clotting factors and platelets. There is a rise in fibrin split products secondary to the destruction of clots. The fibrinogen level decreases as the body uses it up.

Which is true regarding hemophilia A?

It is caused by factor VIII deficiency. Hemophilia A is caused by a deficiency in factor VIII. Hemophilia A is transmitted by an asymptomatic carrier female to an affected son. Hemophilia B is also called Christmas disease. The majority of patients inherit this X-linked recessive disorder

How are laboratory tests used to differentiate the various coagulation disorders?

Laboratory tests evaluate primary and secondary hemostasis. In addition, an abnormal PT/INR indicates a problem with the extrinsic pathway of coagulation, while an abnormal PTT indicates a problem with the intrinsic pathway of coagulation (pgs. 299-301).

Acquired Vitamin K Deficiency

May occur with malnutrition, malabsorption, chronic hepatic disease, antibiotic therapy, oral anticoagulation therapy Results in excessive bleeding Parenteral administration of vitamin K is used for treatment

Vitamin K Deficiency Bleeding in Infancy

Melena- dark tary stool Common in breast fed babies

Fibrinolysis

Occurs as fibrin clot is forming Factor XII, HMWK, kallikrein, and thrombin release plasminogen activators—these cleave plasminogen to form plasmin—plasmin digests fibrinogen and fibrin and inactivates factors V and VIII—fibrin split products result from the dissolution of the fibrin clot

Clinical Assessment

Personal/family history of bleeding disorder Systemic diseases that may be involved Medication history Physical findings such as petechiae, purpura, ecchymosis, hematoma, hemarthrosis, telangiectasia, and occult or frank bleeding

Factors released by platelets contribute to hemostasis by enhancing

Platelet aggregation Platelets, when activated, release factors that lead to vasoconstriction, platelet clumping, and vessel repair. Vasodilation is not caused by platelet factors. The intrinsic pathway and fibrinolysis are steps in clot formation

Thrombocytosis

Platelet count greater than 400,000/mm3 Transitory—due to stress/physical exercise Primary—polycythemia vera or chronic granulocytic leukemia Secondary—response to hemorrhage, disease process, or splenectomy Treatment reserved for primary etiologies with cytotoxic agents and antiplatelet therapy

Platelets (Thrombocytes)

Platelets adhere to subendothelial collagen exposed by trauma After adhesion, they become activated and initiate degranulation, the release of alpha granules and dense bodies Alpha granules and dense bodies release clotting factors that induce platelet aggregation

Thrombocytopenia Description

Splenic sequestration: pooling of blood in the spleen; common with pts with Mononucleosis and Sickle Cell Anemia Very tender spleen

Blood Coagulation Factors

Synthesized by the liver Factors II, VII, IX, X, protein C and S are dependent on vitamin K for synthesis Antithrombin III and protein C promote anticoagulation Protein S assists protein C in binding to phospholipase and stimulates the release of tissue plasminogen activation, initiating fibrinolysis

Vitamin K Deficiency induced bleeding in infancy is characterized by which of the following?

Tarry stools History of breastfeeding Symptoms include bleeding, such as hematuria and melena (tarry, black feces composed of partially digested blood). Hemorrhagic disease of the newborn is more common in breast-fed babies (who do not receive vitamin K supplement) than in formula-fed babies. As the name implies, this coagulation disorder is seen in the newborn, typically 48 to 72 hours after birth, through 6 months of age. It is rare in Western countries because of routine administration of vitamin K to newborns.

What findings from the patient history, physical examination, or laboratory studies would indicate a potential bleeding disorder?

The patient history may indicate whether the bleeding disorder is inherited or acquired. Physical findings may include petechiae, purpura, ecchymosis, telangiectasia, and occult or frank bleeding. Laboratory findings that may indicate a bleeding disorder include CBC, elevated bleeding time, PT or INR, apTT, or decreased platelet count (pgs. 297-301).

Hepatic Disease S/S

pt will have excess bleeding at venipuncture cites and gi bleeding