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Block 4 - Heamatology > Lecture 15- Acquired Bleeding Disorders > Flashcards

Lecture 15- Acquired Bleeding Disorders Flashcards

1
Q

Platelet type bleeding

A
  • skin, mucous membranes (epistaxis, gums, vaginal, GI)
  • cuts bleed
  • petechiae
  • ecchymoses small and superficial
  • haemarthrosis rare
  • bleeding after surgery is immediate and mild
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2
Q

Clotting factor type of bleeding

A
  • site: deep, in soft tissues (joint + muscle)
  • cuts dont bleed
  • no petechiae
  • large, deep ecchymoses
  • comon haemarthrosis, muscle bleeding
  • bleeding after surgery is delayes and severe
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3
Q

Investigating an ABD

A
  • FBC (platelet count)
  • APTT
  • PT (INR)
  • Fibrinogen
  • D-dimers (fibrin generation)
  • thrombin time
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4
Q

Tests of hemostasis: PT

A
  • PT tests extrinsic and common pathways
  • prolonged in disorders affecting factors 7,10,5,2 and 1 (fibrinogen)
  • liver disease, vit K, warfarin therapy, common pathway deficiency
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5
Q

Tests of hemostasis: APTT

A
  • tests intrinsic and common pathways
  • prolonged in disorders affecting 8,9, 10, 12, 11, 5, 2 and I (fibrinogen)
  • Haemophilia A and V, vwf disease
  • inhibitors: heparin, lupus anticoagulant
  • severe liver disease/ Vit K deficiency
  • deficiency factor 11 and 12
  • common pathway deficiency rare
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6
Q
  • Causes of thrombocytopenia
A
  • laboratory artefact
  • increased destruction: immune, drug-induced, DIC, dilutional (massive transfusion)
  • sequestration: splenomegaly
  • decreased production: generalised BM failure due to chemo, drugs, malignancy, alcohol toxicity
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7
Q

What level of thrombocytopenia causes bleeding

A
  • spontaneous bleeding: plat
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8
Q

Causes of increased platelet destrictiuon

A
  • immune idiopathic thrombocytopenic purpura (ITP)
  • other immune causes: autoimmune disease (SLE), drugs (HITTS), malignancy associated antibodies (CLL)
  • Viruses: EBV, HIV
  • alloimmune (post-transfusion)
  • disseminated intravascular coagulation (DIC)
  • thrombotic thrombocytopenic purpura (TTP)
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9
Q

Acute ITP

A
  • more in kids

- treat with steroids, IVIG, splenectomu

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10
Q

Chronic ITP

A
  • more common in adults
  • usually idiopathic
  • SLE, HIV, CLL, autoimmune hemolytic anemia
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11
Q

Diagnosis of ITP

A
  • plat
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12
Q

HITTS and TTP

A
  • not commonly associated with bleeding
  • associated with thrombosis despite low platelet counts
  • HITTS: antibodies complex with heparin and PF4, increased destruction but also platelet activation
  • TTP: congenital or acquired deficiency of VWF cleaving enzyme, fragmentary haemolysis, microvascular effect
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13
Q

Two questions to ask when your patient has low platelets

A
  • have they been exposed to heparin recently (HITTS)
  • are there red cell fragments on this film and a haemolytic anaemia (TTP)
  • speak to hamaematologist urgently: these patients are at risk of clotting, not bleeding
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14
Q

Platelet function disorders

A
  • inherited: membrane defects: bernard-soulier syndrome, Glanzmann thromasthenia
  • acquired: myelodysplasia, myeloproliferative disorders, ureamia, drug (aspirin, clopidogrel, NSAIDS)
  • garlic, ginger, gingko
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15
Q

How are coagulation factors produced

A
  • Liver synthesizes 1,2,5,7,9,10,11 as well as the natural anticoagulants protein C, S and antithrombin III and thrombopoietin, which stimulates megakaryocyte production in BM
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16
Q

Vit K dependent factors

A
  • II (prothrombin)
  • VII, IX, X, Protein C, Protein S
  • Gla-rich tail domains anchor factors to membrane
17
Q

Vit K source

A
  • green leafy vegetable
18
Q

Vit K metabolism

A
  • Dietary Vit K is portein bound
  • released by pancreatic enzymes
  • Bile salts then solubilize it into micells
  • absorbed and incorporated into chylomicrons
  • transported to liver
19
Q

Acquired coagulation disorders:

A
  • Impaired production- liver disease, vit K deficiency
  • Increased destruction (or clearance): disseminated intravascular coagulation, massive transfusion, inhibitors
  • dysfunction: anticoagulant drugs - heparin, warfarin, direct oral anticoagulants
20
Q

AcqHemostasis test in acquired bleeding disorders: liver disease

A
  • Platelets low
  • PT prolonged
  • APTT prolonged
  • TT normal
21
Q

Hemostasis tests in acquired bleeding disorders: DIC

A
  • platelets low
  • PT prolonged
  • APTT prolonged
  • TT very prolonged
22
Q

Hemostasis test in acquired bleeding disorders: Massive transfusion

A
  • platelets low
  • PT prolonged
  • APTT prolonged
  • TT prolonged
23
Q

Hemostasis test in acquired bleeding disorder: heparin

A
  • platelet normal
  • OT normal
  • APTT prolonged
  • TT prolonged
24
Q

Hemostasis test in acquired bleeding disorder: lupus anticoagulant

A
  • platelet normal
  • PT Normal or prolonged
  • APTT prolonged
  • TT normal
25
Q

How can we tell if coag tests are abnormal due to a factor deficiency or an inhibitor (antibody)?

A
  • mixing studies
  • Aka: correction tests using APTT or PT
  • used if unexplained prolongation APTT or PT, mix patient plasma with normal plasma
  • correction = factor deficiency
  • if no correction of APTT: inhibitor
26
Q

Misleading mixing studies

A
  • weak LAC

- time dependent inhibitors (eg: G8)

27
Q

Inhibitors of coag factors

A
  • usually antibodies
  • idiopathic or occur in immune disorders, associated with malignancy, in pregnancy or postpartum
  • occur in inherited factor deficiencies as a complication of treatment
  • directed against: F8, VWF, 9, 10, 5, 13, fibrinogen
  • or non specific: lupus anticoagulant, paraprotein
28
Q

Causes of bleeding in liver disease

A
  • impaired synthesis clotting factors
  • thrombocytopenia (BM suppression, hypersplenism)
  • increased fibrinolysis: decreased clearance of plasminogen, activators, decr synthesis antiplasmin, platelet dysfunction contribution
  • dysfibrinogenemia
29
Q

Contributing factors for coagulopathy

A
  • hypothermia
  • hypotension
  • hypocalcemia/citrate toxicity
  • dilutional factor and platelet deficiency
  • liver damage/dysfunciton/hypoxia
  • disseminated intravascular coagulation
  • transfused products
30
Q

Management of massive blood transfusion and coagulopathy

A
  • good resucitation: restore perfusion
  • keep worm
  • fresh frozen plasma and platelets according to test result
  • cryoprecipitate if low fibrinogen
  • antifibrinolytics
  • distinguish surgical bleeding from coagulopathy
  • factor 7a
31
Q

When clotting leads to excessive bleeding: DIC

A
  • inappropriate and excessive activation of coagulation
  • consumption of platelets and coagulation factors: thrombocytopenia, prolonged coag test, bleeding
  • consumption of anticoagulant and fibrinolysis factors: thrombosis, fibrin deposition, and end-organ damage
32
Q

Causes of DIC

A
  • severe infection
  • malignancy: APML, leukemia, metastatic
  • obstetric: IUFD, placental abruption
  • shock
  • liver disease/failure
  • transplantation - organ rejection
  • extra-corporeal circulation: Cardiac bypass
  • extensive intra-vascular hemolysis - ABO incompatible transfusion
  • snake bite
  • vascular malformations
33
Q

Disseminated intravascular coagulation

A
  • Diagnosis: clinical setting and signs of generalised bleeding, including IV lines and puncture sites
  • coagulation: low platelets, prolonged APTT, PT, TT, low fibrinogen, Raised D-dimer, fragments of red cells on blood filmn
34
Q

Treatment of DIC

A
  • remove or treat cause
  • adequate resuscitaiton
  • fresh frozen plasma and platelets
  • monitor with test results
  • surgical management or delivery of baby
  • cryoprecipitate especially if low fibrinogen
  • surgical management or delivery of baby
  • Heparin only in selected cases: amniotic fluid embolism, foetal death in utero
35
Q

Blood vessels pb with coagulation

A
  • vasculitis
  • connective tissue disorders
  • steroids
  • senile purpura
36
Q

Types of purpura

A
  • palpable purpura: vasculitis, allergic purpura, fibrin activation in subcutaneous tissue
  • non-palpable purpura: small bruises, red cell leakage into tissues (eg: senile pupura)
37
Q

Fibrinolysis

A
  • primary fibrinolysis is really fibrinogenolysis
  • excessive activation of plasminogen
  • causes: trauma, tumours (prostate, pancreas, lung, brain)
  • may be therapeutic

Block 4 - Heamatology (23 decks)

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