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Hematology > Coagulation - Rajan 03.30.15 > Flashcards

Coagulation - Rajan 03.30.15 Flashcards

1
Q

What is Factor V Leiden mutation?

A
  • Normal procoagulant activity
  • Inactivated slowly by activated Protein C
  • INC prothrombinase activity -> failure to remove Va
  • Pts also have increased VIIIa/tenase activity -> V a co-factor for VIII inactivation, but V Leiden unable to do this
  • Extremely common (5-20% of Caucasian pop)
  • Increased risk of venous thromboembolism; 6% of heteros devo VTE by age 65
  • Can exist in combo w/other defects
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2
Q

What is Prothrombin G20210A?

A
  • Mut in 3’ non-coding seq of prothrombin gene
  • Mainly N. European mutation
  • INC prothrombin syn (>115% of normal) - short PT
  • Implicated in both arterial (stroke) and venous thrombosis: <5% heteros devo VTE by 60, and homos devo moderate thrombophilia
  • Pregnancy-related thrombosis and complications
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3
Q

What is hyperhomocysteinemia?

A
  • Acquired (B12, folate) or inherited
  • INC homocysteine = higher atherothrombosis; OR INC dramatically when plasma homocysteine >22 umol/L
  • Mechs unclear, but also increased venous thrombosis
  • Interventional trials haven’t been +
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4
Q

What are some causes of acquired thrombophilia?

A
  • CHF
  • Inflammatory disease
  • Nephrotic syndrome
  • Diabetes
  • MPD, TTP, DIC, HIT, PNH, antiphospholipid syndrome
  • Atherosclerosis
  • Surgery
  • Immobilization, and many more
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5
Q

What are some causes of acquired antithrombin deficiency?

A

Pregnancy, liver disease, DIC, nephrotic syndrome, major surgery, acute thrombosis, heparin, estrogen Rx

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6
Q

What are some causes of acquired Protein C and S deficiencies?

A
  • Protein C: liver disease, DIC, acute thrombosis, Warfarin
  • Protein S: pregnancy, liver disease, DIC, inflammation, acute thrombosis, Warfarin, estrogens Rx
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7
Q

How is a platelet plug formed?

A
  • PLATELETS attach to exposed collagen
  • Aggregation of platelets causes release of chemical mediators (ADP, Thromboxane A2)
  • ADP attracts more platelets
  • Thromboxane A2 (powerful vasoconstrictor): that promotes aggregation & more ADP
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8
Q

Is gangrene a sign of bleeding?

A

No

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9
Q

A 25 year female is evaluated by you for easy bruisability. She has no h/o epistaxis or menorrhagia. Has a brother who also has easy bruising, no other family with bleeding tendency. She has her wisdom teeth extracted with no bleeding two months ago. On exam you note a high arched palate, and she is double jointed. Her Platelet count, FVIII level, von willebrand ag, von willebrand activity, PT and PTT are normal. Her likely diagnosis is:

A

Likely non-hematologic cause, like collagen disorder

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10
Q

What is ristocetin?

A
  • Test used to diagnose von Willebrand’s disease -> abnormal agglutination if disease +
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11
Q

Pt. comes in with bleeding. What is your plan if platelet count is low? What if it is normal?

A
  • Low:
    1. Bone marrow exam
    2. Platelet antibodies
    3. Screening tests for DIC
  • Normal:
    1. Bleeding time
    2. Platelet aggregation studies with ADP, collagen, adrenaline, and ristocetin
    3. O/special platelet tests, e.g., adhesion studies, nucleotide pool measurement
    4. vWF, VIII assays
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12
Q

What are some causes of thrombocytopenia?

A
  • Platelets < 150,000
  • Decreased production of platelets: bone marrow failure, chemo, radiation,
  • Increased destruction: immune thrombocytopenia, HIT, DIC, post-transfusion purpura, von Willebrand disease, Type 2B, hemophagocytosis
  • Increased sequestration: hypersplenism
  • Others: Bernard-Soulier, pseudothrombocytopenia (this mean pt has Abs to EDTA, causing aggregating)
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13
Q

Know these.

A

Good job!

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14
Q

What is immune thrombocytopenia?

A
  • Children: acute, treatable; adults: chronic
  • Dx of exclusion: thrombocytopenia not due to DIC, TTP, HUS, artifact, splenic sequestration, primary bone marrow disease (i.e., to distinguish from CLL), etc.
    1. No specific or sensitive test for ITP -> can order anti-platelet Abs, but discouraged b/c common
    2. Increased MPV; normal PT, PTT
  • Usually, we do nothing for these ppl if platelet counts >50,000 bc these low numbers idiosyncratically do not prolong bleeding time
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15
Q

What is your differential diagnosis? How do you sort this out?

A
  • Differential: B12, folate deficiency, hypersplenism alcohol, medications, myelodysplasia, other bone marrow pathology
  • How do you sort this out?
    1. Obtain a history and examine the patient
    2. Ultrasound of the abdomen (spleen size)
    3. Serum B12, RBC folate
    4. Bone marrow investigation
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16
Q

What are some tests for qualitative platelet abnormalities? KNOW how to interpret this graph.

A
  • Bleeding time
  • Platelet function analysis
  • Platelet aggregation studies
17
Q

What is unique about low platelet count in ITP?

A
  • In people w/normal platelet function, bleeding time not prolonged unless platelet count <100,000/mm3
  • Ppl w/ITP -> often have normal bleeding times despite very low platelet counts
  • Ppl w/qualitative platelet defects, due to aspirin, uremia, or von Willebrand disease, have normal platelet counts, but prolonged bleeding times
18
Q

What are the lab tests for bleeding?

A
  • Prothrombin time (PT)/INR
  • Partial thromboplastin time (PTT)
  • Thrombin time
  • Fibrinogen
  • Factor assays
  • Correction/inhibitors
19
Q

Know this.

A

Good job!

20
Q

Know this.

A
  • Good job!
  • Note: Factor VIII the only factor that goes UP in the context of liver disease
21
Q

Know this one too. What is the important diagnostic feature of the mixing study?

A
  • Lupus anticoagulant: NO CORRECTION ON MIXING STUDY
    1. Having thrombocytopenia with this disease not uncommon (bleeding NOT associated with disease -> CLOTTING)
22
Q

Review this.

A

Good job!

23
Q

What are some of the major distinctions between VIII deficiency and vWF deficiency?

A
  • VIII: X-linked, normal bleeding time, normal vWF levels, hemarthrosis and hematomas
  • vWF: autosomal, prolonged bleeding time, low vWF levels, mucosal bleeding
24
Q

Maybe know this?

A
  • Type III: if vWD totally gone, VIII will be totally gone too
25
Q

Know how to read this.

A
  • Of note, in TTP, vWF is longer
  • In vWF deficiency, it is shorter, or absent
26
Q

What is Hemophilia A?

A
  • 1 in 10,000 Male Births; X-Linked
  • Variable Severity; Hemarthrosis Major Condition
  • Just >5% of Factor VIII- mild disease, 1-5%- Moderate, <1% Severe
  • Therapy with Earlier Cryoprecipitate; Majority of Adult Hemophiliacs Infected HIV
  • **Mild HA; Desmopressin (DDAVP) → ↑VIII **(stimulates release of vWF from endothelial cells)
  • IgG Anti-VIII Inhibitors 10% Patients
  1. Activated Factor IX Complex (II,IX,X,VIIa)
  2. Exchange Plasmapheresis
  3. Increased PTT
27
Q

What is Hemophilia B?

A
  • Xmas Disease; 1 in 100,000 Male Births (X linked)
  • Clinically Identical to Hemophilia A
  • Fresh Frozen Plasma to dilute for hemorrhage
  • Antibody Inhibitors less Common
  • Increased PTT
  • Treatment: Factor IX Concentrate (DDAVP not effective)
  • Associated with Thrombosis - Activated Impurities
28
Q

What is Hemophilia C?

A
  • Deficiency of Factor XI
  • Rosenthal’s Disease
  • Autosomal recessive
  • Ashkenazi Jews
  • PTT prolonged
  • Usually mild symptoms
  • Treatment: FFP
29
Q

What is von Willebrand’s Disease?

A
  • Most Common bleeding diathesis -> 1% prevalence
  • Defect platelet adhesion, ↑ Bleeding time
  • VWF stabilizes Factor VIII and protects it from degradation by activated protein C, and also mediates platelet adhesion
  • Symptoms: mucocutaneous bleed, menorrhagia, epistaxis, bruising, surgical risk
  • Treatment: DDAVP Induces vWF Release, Factor VIII concentrate (high vWF levels)
30
Q

A 22y female with hashimoto thyroiditis, who is currently euthyroid, has been noted with symptomatic cholelithiasis and needs a cholecystectomy. She had wisdom teeth extraction last year with no bleeding. She has no history of epistaxis, menorrhagia or bruising. You perform a CBC, PT and PTT. Her CBC and PT are normal but PTT is prolonged at 45seconds. A mixing study is not corrected. What is the next best step:

A

Lupus anticoagulant testing

31
Q

How does liver disease cause coagulopathy?

A
  • Vitamin K deficiency
  • Thrombocytopenia
  • Decreased production of clotting factors
  • Dysfibrinogenemia
  • Increased fibrinolytic activity
32
Q

What coagulation factors are decreased by liver disease, Vit K deficiency, and DIC?

A
  • Liver disease: V, VII, X
  • VItamin K deficiency: VII, X
  • DIC: V, VII, VIII, X
33
Q

How is Vitamin K involved in coagulation?

A
  • Needed for gamma carboxylation of factors II, VII, IX, X, proteins C & S
  • Warfarin inhibits vitamin K carboxylation, induces deficiency state for over a week.
  • Rapid ↓Factor VII, initially ↑PT, later ↑PTT.
  • Deficiency results from nutritional deficits, antibiotic use, fat malabsorption
34
Q

What are the characteristics of Vitamin K deficiency?

A
  • Mild PT prolongation: asymptomatic
    1. Vitamin K, PO or SC; avoid IM, careful IV
  • Anticoagulant dependent patients
    1. Titrate correction; response 6 - 12 (48) hours
  • Severe ↑PT or Symptomatic -> FFP
  • Liver disease: ↓Factor synthesis, K Stores
    1. Vit K often ineffective -> FFP, cryoprecipitate if low fibrinogen

Hematology (19 decks)

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