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Heme/Onc > Bleeding/Clotting disorders - H/O > Flashcards

Bleeding/Clotting disorders - H/O Flashcards

1
Q

Primary Hemostatic Defect

A
  • Problem with platelets (or vascular wall)
  • Congenital: relatively common
  • Acquired: very common (drugs)
  • Clotting labs normal
  • Prolonging initial bleeding
  • CBC (platelet count)
  • Platelet function testing
  • Von Willebrand panel
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2
Q

Secondary Hemostatic Defect

A
  • Problem with clotting factor(s)
  • Congenital: uncommon
  • Acquired: very rare if so think autoimmune
  • late re-bleeding
  • PT / INR, aPTT, fibrinogen
  • Mixing studies
  • Factor levels
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3
Q

Prothrombin time /INR - what prolongs it

A
  • coumadin
  • liver disease
  • Vitamin K deficiency (II, VII, X)
  • Genetic Factor deficiency (II, V, VII, X)
  • DIC
  • Not enough fibrinogen
  • dysfunctional fibrinogen
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4
Q

Partial Thromboplastin Time (PTT) - what prolongs it?

A
  • Heparin
  • Factor VIII deficiency (hemophilia A)
  • Factor IX deficiency (Hemophilia B)
  • Factor XII deficiency
  • Factor XI deficiency
  • Other factor deficiency (II, V, X)
  • Not enough fibrinogen
  • dysfunctional fibrinogen
  • antiphospholipid antibodies
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5
Q

von Willebrand Disease

A

-Most common inherited bleeding disorder
-Prevalence in general population is ~ 1%
-Many asymptomatic individuals
-Caused by mutations in the gene coding for von Willebrand factor, resulting in quantitative and/or qualitative deficiency
-Functions of von Willebrand factor:
Platelet adhesion to endothelial injury
Plasma carrier of factor VIII
-Autosomal dominant inheritance, males and females affected

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6
Q

von Willebrand Disease: Classification

A 
Type I
-Most common (70%)
-Partial quantitative deficiency
-May be very mild
Type II
-Qualitative abnormalities of vWF - doesnt work as well
-Several subtypes
Type III
-Virtually complete deficiency of vWF
-Rare (~1 in 1 million)
-Autosomal recessive inheritance pattern
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7
Q

von Willebrand Disease: Symptoms

A
  • Clinical presentation depends on severity
  • Epistaxis, dental bleeding, bruising, menorrhagia
  • Prolonged bleeding from wounds (primary hemostasis)
  • Severely affected individuals may have joint and soft tissue hemorrhages
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8
Q

von Willebrand Disease: Diagnosis

A
  • Normal INR
  • Normal or mildly prolonged aPTT
  • Normal platelet count
  • Abnormal PFA-100 (PFCT)
  • Low von Willebrand antigen
  • Low factor VIII
  • Low ristocetin cofactor activity
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9
Q

von Willebrand Disease: Treatment

A
  1. Avoid drugs that inhibit platelet function - ASA, Ibuprofen
  2. DDAVP (desmopressin)/Stimate
    - Synthetic analogue of anti-diuretic hormone (vasopressin)-use high concentration
    - Releases stored vWF from endothelium
    - Given intravenously or inhaled-not orally!
    - Cant use every day
  3. Amicar or Lysteda - oral antifibrinolytics - stops clot from breaking down, doesnt make blood clot form
  4. Plasma derived factor VIII concentrate (Humate-P, Wilate, Alphanate) - if severe VWD
  5. Cryoprecipitate
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10
Q

Hemophilia

A
  • Congenital bleeding disorder caused by deficiency of coagulation factor VIII or IX
  • Genes for factors VIII and IX located on the X chromosome
  • Females are carriers, males are affected
  • High rate of spontaneous mutations: 30% of patients have no family history of hemophilia
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11
Q

Hemophilia A

A
  • Factor VIII deficiency
  • Classical hemophilia
  • 1 in 5,000 to 10,000 male births
  • Hemophilia affects all racial and socioeconomic groups equally
  • There are 20,000 hemophiliacs in the United States
  • 400,000 hemophiliacs worldwide
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12
Q

Hemophilia B

A
  • Factor IX deficiency
  • Christmas disease
  • 1 in 30,000 male births
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13
Q

Hemophilia: Diagnosis

A
  • Normal INR
  • Markedly prolonged PTT
  • Normal platelet count and function
  • Measure specific factor levels
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14
Q

Clinical Features of Hemophilia

A
  • Severity of bleeding tendency depends on the factor level
  • Joint bleed (hemarthrosis)
  • Soft tissue bleeding
  • Deep muscle bleeds
  • Intracranial bleeds

Mild ( > 5% )

  • Bleed only after severe injury, trauma, or surgery
  • May not be diagnosed until adulthood

Moderate (1-5%)

  • Bleed after injury, surgery
  • May have occasional spontaneous bleeding

Severe ( < 1 %)

  • Frequent spontaneous bleeding
  • Diagnosis made in early childhood
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15
Q

Hemophilia: Treatment

A
  • Proper treatment requires direct involvement of specialists experienced in the management of bleeding disorders
  • Avoid drugs that impair platelet function
  • Factor VIII or IX concentrates: Plasma derived (not done anymore), Recombinant
  • On demand vs. prophylactic factor replacement
  • VERY expensive
  • Most of the world’s hemophiliacs do not have access to factor concentrates
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16
Q

Neonatal Vitamin K Deficiency

A
  • In US Vit K is given prophylatically (1mg IM) on day 1 of life.
  • Based on large studies that demonstrated the benefits using clinical bleeding as outcome
  • Neonates are high risk due to low placental transfer and limited liver storage
  • Some risk groups require additional prophylaxis
  • Alpha-1 antitrypsin def , chronic diarrhea, CF and celiac dz.
  • Mothers on anticonvulsant therapy during pregnancy
17
Q

Adult Vitamin K Deficiency

A

CAUSES

  • Chronic or severe illness
  • Malnutrition-chronic TPA, alcoholism, IBD
  • Parenchymal liver disease
  • Cystic fibrosis
  • Drugs - Antibiotics (cephalosporin), cholestyramines, warfarin, salicylates, anticonvulsants, and certain sulfa drugs are some of the common causes of VK deficiency

TREATMENT

  • VK-1 should be administered subcutaneously or intramuscularly.
  • If there is a high risk for hematoma formation with intramuscular or subcutaneous VK administration, then an oral form of VK can be administered
  • The absorption with the oral form is variable because it requires bile salts in the ileum for absorption. This form is used in the setting of asymptomatic VK deficiency.
18
Q

What happens when we have too much hemostasis ?

A
  • Arterial Thrombosis: stroke, heart attack

- Venous Thromboembolism: DVT, PE

19
Q

Genetic Thrombophilia

A

Factor V Leiden and Prothrombin Gene Mutation

  • Autosomal dominant inheritance
  • Single point mutations
  • Well-known, and VERY common
  • Many asymptomatic carriers

Protein C deficiency and Protein S deficiency or Antithrombin-III deficiency

  • Autosomal dominant inheritance
  • Many different mutations described
  • Well-known, but uncommon
  • Usually have strong family history of thrombosis
  • Dysfibrinogenemia
  • Elevated levels of factors VIII, IX, XI, and fibrinogen are also probably inherited hypercoagulable state
20
Q

Mechanisms of Thrombosis in Inherited Thrombophilia

A
  1. Failure to control thrombin generation
    - Factor V Leiden heterozygote = 5 – 7 fold increased risk
    - Prothrombin Gene Mutation
    - Protein C deficiency
    - Protein S deficiency
  2. Impaired neutralization of thrombin
    - Antithrombin-III deficiency
21
Q

Acquired Thrombophilic Conditions

A
  • Antiphospholipid antibodies
  • Malignancy
  • Inflammatory Bowel Disease
  • Nephrotic syndrome
  • Myeloproliferative Disorders
  • PNH
  • CHF
  • Sepsis / DIC
  • HIT
22
Q

Acquired Triggers for Thrombosis

A
  • Immobilization
  • Surgery
  • Trauma
  • Pregnancy / Postpartum
  • Estrogens (OCPs, HRT) = 3 – 4 fold increased risk
  • Older Age
23
Q

Diagnosis of VTE

A
  1. Clinical signs and symptoms
  2. Lab testing: D-dimer
    - Breakdown of cross-linked fibrin clots releases D-dimers
    - D-dimer levels can be measured by laboratory tests
    - Elevated levels may also be seen with: cancer, infection, trauma, surgery, pregnancy, inflammation
    - Elevated levels may persist for 3+ weeks
  3. Non-Invasive Imaging
    • Compression ultrasound: Unable to compresses vein = DVT
    • V/Q scan
    • CT scan
  4. Invasive Imaging
    • Venography
    • Pulmonary angiography
24
Q

DVT: Clinical Findings

A
  • Pain
  • Swelling
  • Tenderness
  • Discoloration
  • Warmth
  • Asymmetry
25
Q

PE: Clinical Findings

A
  • Dyspnea
  • Chest Pain
  • Anxiety
  • Cough
  • Hemoptysis
  • Sudden Death
26
Q

Treatment of Venous Clots

A

-Heparin-unfractionated
-Low MW Heparin
enoxaparin (Lovenox)
dalteparin (Fragmin)
-Factor Xa Inhibitor
fondaparinux (Arixtra)
-Direct thrombin inhibitors
lepirudin
argatroban
bivalirudin

Long term: Warfarin, coumadin, jantoven

27
Q

Treatment of Venous Clots

A
  1. The best way to treat a clot is to prevent it from forming in the first place
  2. Anti-platelet medications offer NO PROTECTION against venous thrombosis
  3. Anti-platelet drugs, warfarin, and heparins DO NOT dissolve clots directly
  4. Treatment decisions MUST include an assessment of the risks: recurrent clot vs. bleeding
  5. All long term treatment decisions should be re-evaluated periodically to be sure the benefits still outweigh the risks
  6. New drugs are different, not necessarily better

Heme/Onc (8 decks)

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