Hematology lec 3 : Coagulation and bleeding disorders (Hemostasis) Flashcards
A 32-year old woman observes the presence of multiple petechiae, purpura and ecchymosis rashes when she wakes up in the morning . She had a history of epistaxis requiring cauterization.
- Platelet count 50 x 109/L (RI 150-400 x 109/L)
- Bleeding time 10 min (RI 2-7 min)
This woman might be suffering from???????
Immune thrombocytopenic purpura
Components of hemostasis
- normal blood vessels
- clotting cascade
- platelets
Hemostasis depends on a delicate balance between ………………….and …………… mechanisms
procoagulant , anticoagulant
Mechanismm of intrinsic pathway of blood coagulation
XIIa + XIa + lXa + Xa
اتناشر حداشر تسعة بمساعدة تمانية يبدأ الكومن باثوي ب عشرة
Mechanism of Extrinsic pathway of blood coagulation
Tissue factor + VIIa + Xa
باثوي قصير وكل حاجة فيه بسيطة
Mechanism of coagulation common pathway
Xa + (prothrombin) II to (thrombin) IIa , then Fibrinogen to Fibrin
نووتتسس عشرة محتاج مساعدة من خمسة(نصه التاني) والكالسيوم
Test of intrinsic pathway :
PTT
Test of Extrinsic pathway :
PT
Screening tests: done for all suspected patients
⚫Bleeding time ⚫Platelet count ⚫Prothombin time (PT) ⚫Partial thromboplastin time (PTT) ⚫Thrombin time (TT)
Specific tests : done according to results of……………….
screening tests
Bleeding time Affected by
�Platelet count
�Platelet function
�Vessel wall
Normal range OF Bleeding time
Ivy’s method: up to 7 min
Causes of prolonged bleeding time:
1-Thrombocytopenia (moderate or severe). 2-Disorders of platelet function: Thrombasthenia 3-Vascular abnormalities
Normal platelet count =
150-400 x109/L
Investigation of a case of thrombocytopenia
⚫ History
⚫ CBC
⚫ Bone Marrow
⚫ ANA
QUALITATIVE PLATELET
DEFECT (Thrombasthenia)
In a case presenting with …………….. and
……………………………….
purpura , normal platelet count
PROTHROMBIN TIME (PT) Test for ……………….
extrinsic pathway (FVII, FX, FV , FII, FI) - [majority are vitamin K dependent factor].
Normal range of PROTHROMBIN TIME (PT):
10-14 sec