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YA - Interactive seminars/University lectures > HAEM - bleeding disorders > Flashcards

HAEM - bleeding disorders Flashcards

1
Q

What does Activated Partial thromboplastin time (APTT) measure?

A

Intrinsic pathway coagulation (factors 8, 9, 11, 12)

Surface activating agent (Ellagic acid, kaolin)
Phospholipid
Calcium

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2
Q

What does Prothrombin time (PT) measure?

A

Extrinsic pathway (factor 7)

(remember PT is used for INR and INR is related to vitamin K & warfarin. Vitamin K helps produce factors 2, 7, 9, 10, and factor 7 is uniquely in EXTRINSIC - hence it measures extrinsic pathway)

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3
Q

What does Thrombin time measure?

A

Common pathway

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4
Q

(4) features of screening tests for hemostatic defects

A
  • Platelet Count (150 - 400)
  • Activated Partial Thromboplastin Time (Aptt) (24-32 Seconds)
  • Prothrombin Time(pt)(10 -12 Seconds)
  • Thrombin Time
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5
Q

How can you differentiate factor deficiency from presence of ‘inhibitor’ in coagulation?

A

Perform Mixing study:
Mix 1/2Pt + 1/2 Control (CONTROL - POOLED PLASMA from normal individuals) and perform APTT or PT

  • If factor deficiency = APTT / PT will normalize (the control pool will make up for the deficiency)
  • If ‘inhibitor’present = persistent abnormality (inhibitor will affect the control pool also)
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6
Q

(3) Causes of corrected APTT after Mixing study in previously normal PT, prolonged APTT

A
  • Factor deficiency (VIII, IX, XI, XII)
  • Early DIC
  • Heparin Rx (variable correction)
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7
Q

(2) Causes of persistent abnormality after Mixing study in previously normal PT, prolonged APTT

A
  • Lupus anticoagulant (common)

- Inhibitors towards specific coagulant factors VIII, IX, XI

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8
Q

(3) Causes of corrected PT after Mixing study in previously prolonged PT, normal APTT

A
  • Factor deficiency (VII)-rare
  • Liver disease, Vit K defi
  • Warfain (above are common)
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9
Q

(2) Causes of persistent abnormality after Mixing study in previously prolonged PT, normal APTT

A
  • Antiphospholipid ab’s: uncommon

- Antibodies to VII: rare

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10
Q

(2) Causes of corrected PT/APTT after Mixing study in previously prolonged PT, prolonged APTT

A
  • Isolated deficiency in common pathway: Factors V, X, II, and fibrinogen
  • Multiple factor deficiencies (common): Liver disease, vitamin K deficiency, warfarin, DIC
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11
Q

(3) Causes of persistent abnormality after Mixing study in previously prolonged PT, prolonged APTT

A
  • Inhibitors towards V, X, II
  • fibrinogen (rare)
  • anti-phospholipid ab’s
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12
Q

(5) causes of prolonged PT

A
  • Warfarin (F II, VII, IX, X)
  • Liver disease
  • Vitamin K deficiency
  • DIC
  • Factor VII deficiency
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13
Q

(7) causes of prolonged APTT

A
  • Heparin anticoagulation therapy
  • Liver disease
  • Lupus anticoagulant
  • DIC
  • von Willebrand’s disease
  • Haemophilia: Factor VIII, Factor IX deficiency
  • Factor XII, XI deficiency
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14
Q

(3) causes of prolonged thrombin time (TT)

A
  • DIC (decreased fibringogen)
  • Liver disease
  • Heparin
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15
Q

Describe purpuric disorders

  • petechiae
  • superficial echymoses
  • haematoma & haemarthrosis
  • late bleed
  • gender
  • FMHx
A

Purpuric disorders have characteristic petechiae, small & multiple superficial echmoses

  • rare haematoma, haemarthrosis
  • rare late bleed
  • females > males
  • variable FMHx
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16
Q

Describe coagulation disorders

  • petechiae
  • superficial echymoses
  • haematoma & haemarthrosis
  • late bleed
  • gender
  • FMHx
A

Coagulation disorders have rare petechiae, large & solitary superficial echymoses

  • characteristic haematoma & haemarthrosis
  • common late bleed
  • 80-90% males
  • common FMHx
17
Q

(4) Common hereditary bleeding disorders

A
  • Hemophilia – A /B
  • Von Willebrand disease
  • Factor deficiency
  • Platelet Disorders
18
Q

(5) common acquired bleeding disorders

A 
–Liver disease
–Vit K deficiency
–DIC
–Excessive anticoagulation
–ITP (idiopathic thrombocytopaenic purpura)
19
Q

(2) functions of vWF

A
  1. vWF mediates platelet adhesion at site of injury
  2. Stabilizes FVIII in circulation

Remember: Wherever platelet aggregation is needed, coagulation is also necessary. vWF is like a ‘taxi’ that carries fVIII to the proximity of a developing clot

20
Q

What modifies penetrance of type I von Willebrand disease?

A

ABO group

  • ABO glycosylation of vWF influences clearance
  • People with non-O blood group have higher levels compared with O-group
  • Blood group AB people have highest level
21
Q

Describe type 1, 2, 3 of von Willebrand’s disease

A

Type 1 -partial quantitative deficiency of VWF
–70-80% cases- Ad
–Mild presentation / blood group.

Type 2 -qualitative deficiency of VWF

  • Subtypes : Differences in multimers
  • Mild to moderate bleeding.
  • Abnormal Multimers

Type 3- virtually complete deficiency of VWF

All have prolonged APTT

22
Q

Specific Ix for vWD (von Willebrand’s disease)

A
  • von Willebrand Factor Antigen (vWAg)
  • Factor VIII clotting activity : VIII C
  • Functional assays : Ristocetin Co-Factor activity/Collagen-binding assay
23
Q

Rx for vWD

A
  • Desmopressin (DDAVP): Releasing FVIII & vWFAg from storage sites. Effective in Type 1.
  • Replacement Therapy
  • Antifibrinolytics - Tranexamic acid
  • Fibrin Glue / Fibrillar collagen preparation
24
Q

Explain pathophysiology of haemophilia A

  • factors involved
  • genetics
A

–Factor VIII deficiency
–F VIII normally circulates bound to vWf, which protects F VIII from proteolysis

Genetics:
–X-linked recessive (gene on X chromosome)
–Males present with features of disease (males = XY)

25
Q

Clinical Px of haemophilia A

A

–Hemarthrosis
–Subcutaneous and intramuscular haematomas
–Psoas and retroperitoneal haematomas
–Traumatic bleeding:
•Bleeding from razor nicks is uncommon
•Delayed bleeding is common especially in tooth extractions, tonsillectomy
•Wound healing is slow in haemophiliacs

26
Q

Which clotting profile would be abnormal in haeomphilia A?

A

APTT (factor 8 deficient)

INR is normal

27
Q

Rx of haemophilia A

A

–Purified or Recombinant F VIII therapy
–Tranexamic acid
–Topical thrombin
–Role of FFP

28
Q

Describe haemophilia B

  • factor involved
  • prevalance compared to haem A
  • genetic
A
  • Factor IX deficiency
  • 4-8 times less common than Haemophilia A
  • X-linked recessive
  • Unlike Haemophilia A, spontaneous mutation rate is low, most patients have family history
  • Severe disease manifests identical to Haemophilia A
29
Q

Which factor is deficient in haemophilia A?

A

Factor 8

30
Q

Which factor is deficient in haemophilia B?

A

Factor 9

31
Q

Ix of haemophilia B

A

–Prolonged APTT (factor 9 deficiency), Normal INR

–APTT not sensitive to mild deficiency (F IX 20-30%)

32
Q

Rx of haemophilia B

A

–Prothrombin complex

–Purified or Recombinant F IX

33
Q

What is thrombocytopaenia?

A

deficiency of platelets in the blood.

This causes bleeding into the tissues, bruising, and slow blood clotting after injury

34
Q

What are the causes of thrombocytopaenia?

  • increased destruction
  • decreased production
A

Increased destruction

  1. Auto-Immune:
    - ITP
    - SLE etc
    - Drugs
  2. Allo-immune:
    - Post Transfusion Purpura
    - Neonatal Allo-Immune Thrombocytopenia
  3. Non-immune:
    - Hypersplenism
    - DIC / TTP / HUS

Decreased production

  • Aplastic Anaemia
  • Myelodysplasia
  • Leukaemic infiltration
  • Lymphoma infiltration
  • Fibrosis
35
Q

Where do you typically bleed in thrombocytopaenia?

A 
•Skin and mucous membranes
–Petechiae
–Ecchymosis
–Hemorrhagic vesicles
–Gingival bleeding and epistaxis
  • Menorrhagia
  • Gastrointestinal bleeding
  • Intracranial bleeding
36
Q

(4) How do you assess the function of platelets?

A
  1. Thromboelastography (TEG)
  2. PLATELET AGGREGATION STUDIES
    - ADP
    - COLLAGEN
    - ADRENALINE
    - RISTOCETIN
  3. Plt Function Analysis (PFA)
  4. Skin Bleeding Time: No longer preferred as technical issues of standardization and expertise

YA - Interactive seminars/University lectures (87 decks)

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