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D&T - E1 > Bleeding Disorders > Flashcards

Bleeding Disorders Flashcards

1
Q

Causes of Excessive Bleeding

A
  • Increased vessel fragility
  • Platelet deficiency or dysfunction
  • Derangement of coagulation
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2
Q

Laboratory Coagulation Tests

A

Primary Hemostasis

  • Platelet count
  • Bleeding time (BT)
  • Platelet function analysis (PFA)

Secondary Hemostasis

  • Partial thromboplastin time (PTT)
  • Prothrombin time (PT)
  • Mixing Study
  • Clotting Factors
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3
Q

Laboratory Coagulation Tests - Primary Hemostasis - Platelet Count

A
  • Normal range 150K - 400K/uL

- False lows: platelet clumps/ fibrin strands (traumatic draw)

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4
Q

Laboratory Coagulation Tests - Primary Hemostasis - Bleeding Time

A

Not standardized

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5
Q

Laboratory Coagulation Tests - Primary Hemostasis - Platelet Function Analysis (PFA)

A
  • Stimulates in vivo condition - high shear stress
  • Utilizes platelet agonists (collagen/ADP and collagen/EPI) to interrogate platelet function
  • Has replaced bleeding time in many institutions because more standardized

Interpretation:

  • Normal A and E: normal
  • Normal A, prolonged E: drug effect (ASA)
  • Both prolonged: vWD
  • Both prolonged: platelet abnormality
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6
Q

Laboratory Coagulation Tests - Secondary Hemostasis - Partial Thromboplastin Time (PTT)

A
  • Kaolin + cephalin + Ca2+ + patient plasma

- Intrinsic and common pathway: VIII, IX, XI, XII; II, V, X, XII, Fibrinogen

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7
Q

Laboratory Coagulation Tests - Secondary Hemostasis - Prothrombin Time (PT)

A
  • Tissue thrombplastin + Ca2+ + patient plasma

- Extrinsic and common pathway: VII; II, V, X, XIII, Fibrinogen

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8
Q

Laboratory Coagulation Tests - Secondary Hemostasis - Mixing Study

A
  • Patient sera + pooled sera: check PTT (or PT)
  • If PTT normal (corrects) then FACTOR DEFICIENCY
  • If PTT abnormal (no correction) then INHIBITOR PRESENT
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9
Q

Laboratory Coagulation Tests - Secondary Hemostasis - Clotting Factors

A
  • Known specific factor-poor plasma + Patient plasma

- Run either PT or PTT depending on which factor being evaluated

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10
Q

Abnormalities of the Vessel Wall - Clinical Picture

A
  • Petechiae

- Purpura

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11
Q

Abnormalities of the Vessel Wall - Coagulation Test Results

A

Normal

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12
Q

Abnormalities of the Vessel Wall - Etiologies

A
  • Drugs
  • Impaired Collagen Support
  • Henoch-Schonlein Purpura
  • Hereditary Hemorrhagic Telangiectasia
  • Amyloid Infiltration
  • DIC
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13
Q

Abnormalities of the Vessel Wall - Etiologies - Drugs

A

Drug-induced immune complexes deposit in the vascular wall leading to leukocytoclastic vasculitis

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14
Q

Abnormalities of the Vessel Wall - Etiologies - Impaired Collagen Support

A
  • SCURVY: vitamin C deficiency, required for hydroxylation of procollagens
  • EHLERS-DANLOS SYNDROME: inherited collagen abnormalitiy
  • Elderly
  • CUSHING SYNDROME: excessive steroids = protein wasting = loss of vascular support
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15
Q

Abnormalities of the Vessel Wall - Etiologies - Henoch-Schonlein Purpura

A
  • Systemic hypersensitivity disease in which circulating immune complexes deposit in the vessels
  • Unknown etiology
  • Colicky abdominal pain, polyarthralgias, acute glomerulonephritis
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16
Q

Abnormalities of the Vessel Wall - Etiologies - Hereditary Hemorrhagic Telangiectasia

A
  • AD

- Dilated tortuous vessels within thin walls

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17
Q

Abnormalities of the Vessel Wall - Etiologies - Amyloid Infiltration

A

Weakens vessel walls

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18
Q

Thrombocytopenia - Clinical Findings

A
  • Normal platelet count: 150,000 - 400,000

- Typically not a problem until count

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19
Q

Thrombocytopenia - Coagulation Test Results

A
  • Platelet count decreased

- BT and PFA prolonged if platelet

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20
Q

Thrombocytopenia - Etiologies

A

Decreased Production (bone marrow)

  • Neoplastic
  • Non-neoplastic

Increased Peripheral Destruction/Sequestration

  • Non-immune
  • Allo-immune Condition
  • Auto-immune Conditions (immune thrombocytopenia purpura, heparin induced thrombocytopenia, HIV associated, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome)
  • Dilutional Effect secondary to Massive Transfusions
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21
Q

Thrombocytopenia - Etiologies - Decreased Bone Production - Neopastic

A
  • Non-hematopoietic neoplasms infiltrating marrow (prostate, breast, neuroblastoma, etc.)
  • Hematopoietic neoplasms (AML, ALL, MDS, lymphoma, etc.)
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22
Q

Thrombocytopenia - Etiologies - Decreased Bone Production - Non-neoplastic

A
  • Infections
  • Drugs
  • EtOH, toxins
  • B12/Folate deficiency
23
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Non-immune

A
  • SEQUESTRATION: splenomegaly (hypersplenism)

- MECHANICAL DAMAGE: prosthetic heart valves, malignant hypertension

24
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Allo-immune Condition

A
  • One person develops antibodies to platelets after being to platelets of another person
  • Rare because most people ave similar platelet antigens
  • May cross placenta causing fetal thrombocytopenia
25
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Auto-immune Conditions - Immune Thrombocytopenia Purpura (ITP)

A
  • Primary (idiopathic autoimmune platelet destruction vs Secondary (identifiable etiology causing autoimmune platelet destruction)

Chronic ITP

  • Adults
  • Insidious onset of symptoms
  • Secondary etiologies include SLE, HIV, drugs and other viruses
  • Peripheral blood shows thrombocytopenia with giant platelets reflected by INCREASED MPV
  • IgG autoAb against platelet antigens (Gp IIb-IIIa or Gp Ib-IX)
  • Abs bind to platelets, platelets are then opsonized and removed by reticuloendothelial system (spleen)
  • Spleen - NORMAL SIZE; congestion of sinusoids, macrophages, splenic follicular hyperplasia, occasional megakaryocytic
  • Bone marrow examination done only if patient not responsive to therapy to exclude other etiologies of thrombocytopenia; shows INCREASED NUMBERS OF MEGAKARYOCYTES with left shifted maturation
  • TREATMENT: immunosuppression with steroids; splenectomy, IVIG, rituximab (CD20 antibody)

Acute ITP

  • Kids
  • Abrupt onset of thrombocytopenia
  • Preceded by viral illnesses (2 weeks)
  • Self limited, resolves in 6 months
  • 20% of kids will persist beyond 6 months (chronic ITP similar to adults)
26
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Auto-immune Conditions - Heparin Induced Thrombocytopenia (HIT)

A

Type I

  • Most common; due to direct platelet aggregation caused by heparin
  • Moderate thrombocytopenia
  • Occurs within a few days of heparin
  • Clinically insignificant

Type II

    • 5-14 days after heparin is started or sooner if patient has been previously sensitized with heparin
  • Moderate to severe drop in platelets
  • Antibodies directed against heparin-platelet factor 4 complex results in direct platelet activation
  • Paradoxical thrombosis due to platelet activation
  • LIFE THREATENING - MUST DISCONTINUE HEPARIN
  • If patient has history of HIT lovenox (LMW heparin) is also contraindicated
  • BUT risk of developing HIT is less with LMW heparin
27
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Auto-immune Conditions - HIV Associated

A
  • Common problem
  • CD4 is present on surface of megakaryocytic
  • Direct infection of megakaryoctes by HIV
  • HIV results in dysregulation and hyperplasia of B cells
  • Autoantibody production towards platelet Gp IIb-IIIa
28
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Auto-immune Conditions - Thrombotic Thrombocytopenia Purpura (TTP)

A

Classic pentad of clinical findings

  • Fever
  • Thrombocytopenia
  • Microangiopathic hemolytic anemia (dx: schistocytes, increase LDH, indirect hyperbilirubinmemia)
  • Neurologic symptoms: seizures, altered mental status, hemiplegia, parasthesias, visual defects, aphasia
  • Renal failure

Hyaline thrombi (platelet aggregates) formation

  • Platelet consumption = thrombocytopenia
  • Red cell trapping in microthrombi = microangiopathic hemolytic anemia (schistocytes)
  • Organ dysfunction

ADAMTS 13 Deficiency

  • Normally: ADAMS 13 degrades HMW multimers of vMF
  • DEFICIENCY: accumulation of of HMW multimers which can promote platelet aggregation
  • ACQUIRED: autoantibody against ADAMTS 13
  • INHERITED: inactivating mutation in gene
  • Endothelial cell injury can exacerbate

Treatment of TTP is total plasma exchange to remove autoantibody and replenish normal levels of ADAMTS 13
- Platelet transfusions are CONTRAINDICATED - worsen the thrombi

29
Q

Thrombocytopenia - Etiologies - Increased Peripheral Destruction/ Sequestration - Auto-immune Conditions - Hemolytic Uremic Syndrome

A
  • Presents with bloody diarrhea and subsequent renal failure
  • Often associated with E. coli strain 0157 - H7
  • Occurs more in kids
  • HUS patient have normal levels of ADAMTS 13 enzyme
  • Treatment is supportive care, value of plasma exchange is unclear
30
Q

Platelet Function Abnormalities - Clinical Findings

A

Prolonged bleeding after cuts/trauma

31
Q

Platelet Function Abnormalities - Coagulation Test Results

A
  • PT, PTT, platelet count normal
  • PFA - abnormal
  • Platelet aggregation studies: examines the functionality of platelets when stimulated with various agonists: collagen, ADP, eli, thrombin, ristocetin
32
Q

Platelet Function Abnormalities - Etiology

A

Acquired

  • Drugs: ASA, NSAIDs, many others
  • Uremia: unknown pathogenesis

Congenital

  • Platelet adhesion defect: Bernard-Soulier
  • Platelet aggregation defect: Glanzmann’s Thrombasthenia
33
Q

Platelet Function Abnormalities - Etiology - Congenital - Bernard-Soulier

A
  • AR
  • Deficient platelet Gp Ib-IX complex where vWF needs to bind
  • vWF linkes platelets to endothelium
  • Giant platelets
  • Platelet aggregation: EVERYTHING WORKS BUT RISTOCETIN
34
Q

Platelet Function Abnormalities - Etiology - Congenital - Glanzmann’s Thrombasthenia

A
  • AR
  • Deficient Gp IIb-IIIa which is the place where fibrinogen cross links between platelets
  • Platelet aggregation: NOTHING WORKS BUT RISTOCETIN
35
Q

Clotting Factor Abnormalities - Clinical Findings

A
  • Prolonged bleeding after laceration, surgery or trauma
  • Bleeding into GI/GU tract
  • Bleeding into weight bearing joints
36
Q

Clotting Factor Abnormalities - Coagulation Test Results

A

Depends on which factor is deficient

37
Q

Clotting Factor Abnormalities - Etiologies

A
  • von Willebrand Disease
  • Factor VIII Deficiency (Hemophilia A)
  • Factor IX Deficiency (Hemophilia B, Christmas Disease)
  • Acquired Deficiencies
38
Q

Clotting Factor Abnormalities - Etiologies - von Willebrand Disease

A
  • Prolonged bleeding from cuts, menorrhagia, mucous membrane bleeding
  • Abnormal PFA and PTT; normal platelet count
  • AD usually; 1% of population
  • Different subtypes with severity of symptoms dependent on which subtype
Type I (70%)
- QUANTITATIVE decrease in vWF -
39
Q

Clotting Factor Abnormalities - Etiologies - Factor VIII Deficiency (Hemophilia A)

A
  • VIII is the cofactor for IX
  • X linked recessive
  • Males and homozygous females
  • Heterozygous females can be symptomatic due to unfavorable LYONIZATION
  • 30% of families have no family history - new mutations
  • ## Clinical symptoms correlate with VIII level
40
Q

Clotting Factor Abnormalities - Etiologies - Factor VIII Deficiency (Hemophilia A) - Symptoms

A
  • Easy bruising, massive hemorrhage after surgery/trauma
  • Spontaneous hemorrhage into large joints = hemarthroses
  • NO mucous membrane bleeding or petechiae
41
Q

Clotting Factor Abnormalities - Etiologies - Factor VIII Deficiency (Hemophilia A) - Diagnosis

A
  • Prolonged PTT
  • Normal PFA, platelet count, PT
  • Factor VIII assay (functional)
42
Q

Clotting Factor Abnormalities - Etiologies - Factor VIII Deficiency (Hemophilia A) - Treatment

A
  • Humate P (purified, plasma derived) or recombinant (Kogenate)
  • Purified and recombinant VIII virtually eliminates infectious risk
  • Inhibitor development is still a risk of replacement therapy
43
Q

Clotting Factor Abnormalities - Etiologies - Factor VIII Deficiency (Hemophilia A) - Why do symptoms occur if only one arm of cascade is knocked out?

A
  • Tests may not reflect true, in vivo reality
  • Fibrin formation/deposition is inadequate to maintain clot (extrinsic role is the burst to get the cascade moving; intrinsic pathway maintains it)
  • Inappropriate fibrinolysis (high levels of thrombin needed to activate TAFI (inhibits fibrinolysis); this does not occur with only one pathway working
44
Q

Clotting Factor Abnormalities - Etiologies - Factor IX Deficiency (Hemophilia B)

A
  • Clinically identical to Factor VIII deficiency (remember, VIII and IX work together to activate X)
  • X linked recessive with variable clinical severity
  • 14% of patients have normal levels of IX, BUT ABNORMAL FUNCTION
  • DIAGNOSIS: prolonged PTT; normal PT, PFA, platelet count; factor IX assay (functional)
  • TREATMENT: recombinant factor IX
45
Q

Clotting Factor Abnormalities - Acquired Deficiencies

A

Vitamin K Deficiency

  • II, VII, IX, X, protein C
  • This is how Coumadin works

Liver disease
- Majority of coagulation cascade proteins are made in the liver

DIC

46
Q

Disseminated Intravascular Coagulation

A

Not a primary disease - rather is a physiologic consequence of other disease

  • Thrombohemorrhagic disorder
  • Pathologic activation of the coagulation cascade systemically in the microvasculature
  • Signs/symptoms related to tissue hypoxia and infarction and/or hemorrhage due to consumption of coagulation factors
47
Q

Disseminated Intravascular Coagulation - Coagulation Tests

A
  • Prolonged PT, PTT
  • Decreased platelet
  • Decreasing fibrinogen
  • Increased d-dimer
48
Q

Disseminated Intravascular Coagulation - Etiologies

A

Obstetric Complications

  • Placental abruption
  • Retained products of conception
  • Septic abortion

Infections

  • Gram negative sepsis
  • Meningococcemia

Neoplasms

  • APL (AML-M3)
  • Adenocarcinoma

Massive Tissue Injury

49
Q

Disseminated Intravascular Coagulation - Mechanisms

A

Tissue factor release into the blood

  • Obstetric complications
  • Substance released by blasts of APL
  • MUCIN of adenocarcinoma released into blood directly activating X
  • Gram negative sepsis with bacterial endotoxins result in release of IL-1 and TNF which increase the TF on endothelial cells

Wide spread endothelial cell injury

  • Infectious etiologies via TNF production (increases leukocyte adhesion and free radical formation which damages endothelium)
  • Antigen/antibody complex deposition (SLE)
  • Heat stroke, burns
50
Q

Disseminated Intravascular Coagulation - Consequences

A

Widespread fibrin deposition in microvasculature

  • Ischemia of associated organs (ischemic bowel, renal failure, hepatic necrosis, skin/digit necrosis)
  • Hemolytic anemia (microangiopathic; schistocytes on smear)

Hemorrhagic diathesis

  • Factor and platelet consumption faster than production
  • Plasminogen activation (fibrinolysis in increased d-dimer/FDPs which inhibit platelet aggregation and have antithrombin activity)
51
Q

Disseminated Intravascular Coagulation - Morphology

A
  • Thrombi in brain, heart, lungs, kidneys, adrenals, spleen and liver
  • CNS micro-infarcts/hemorrhage with associated symptoms
  • Waterhouse-Friderichsen Syndrome (massive bilateral adrenal hemorrhage associated with meningococcus)
  • Sheehan Syndrome - postpartum pituitary necrosis
  • Toxemia of pregnancy - microthrombi in placenta
52
Q

Disseminated Intravascular Coagulation - Clinical Course and Prognosis

A

Acute, fulminent - typically present with bleeding

  • Endotoxic shock, trauma
  • Obstetric complications
  • APL

Chronic, insidious - typically presents with thrombosis
- Carcinomatosis

Presentation

  • Microangiopathic hemolytic anemia
  • Dyspnea, cyanosis, respiratory failure
  • Convulsions, coma
  • Oliguria, acute renal failure
  • Circulatory shock
53
Q

Disseminated Intravascular Coagulation - Coagulation Findings

A
  • Decreased platelets
  • Prolonged PT and PTT
  • Decreasing fibrinogen
  • Peripheral smear

Peripheral smear

  • Schistocytes with compensatory increase in reticulocytes/nRBS’s if marrow stores available
  • Leukocytosis and neutrophilia, sometimes with LEFT SHIFT; toxic changes
  • Decreased numbers of platelets; giant platelets
54
Q

Disseminated Intravascular Coagulation - Treatment

A
  • Treat underlying problem/illness

- Supportive care

D&T - E1 (11 decks)

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