This document discusses platelet disorders, coagulation disorders, and vascular disorders that cause purpura. It describes thrombocytopenic purpura which is caused by a platelet deficiency, and thrombasthenic purpura which is a functional platelet disorder. Coagulation disorders discussed include hemophilia A, B, and C which are hereditary deficiencies in coagulation factors VIII, IX, and XI respectively. Tests to detect defects in platelet function and coagulation pathways are also outlined.

1. Dr Ambika Jawalkar

2. I. Platelet disorders
II. Coagulation disorders/defective
coagulation mechanism
III. Vascular disorders (Non-
thrombocytopenic purpura)

3.  Thrombocytopenic purpura – deficiency of
platelets
*essential / idiopathic(ITP)
*secondary
 Thrombasthenia – functional disorder of
platelets (defect in adhesion / aggregation)
eg: aspirin, large doses of penicillin, von
Willibrand’s disease

4.  Deficiency of clotting factors
* Hemophilia
 Vitamin K deficiency
 Anticoagulant overdose
 Disseminated intravascular clotting (DIC)

5.  Drug induced damage to capillary wall
 Deficiency of vitamin C – Scurvy
 Allergic purpura
 Infections
 Senile purpura
 Connective tissue diseases

7.  Group of bleeding disorders
 Characteristic features are,
*purple-colored petechial haemorrhages
*bruises in the skin

8. CAUSES:
1. Platelet disorders
Thrombocytopenic purpura – primary,
secondary
Thrombosthenic purpura – vWD
1. Vascular disorders – non-
thrombocytopenic purpura

9. “group of disorders occouring due to
heriditary deficiency of coagulation”
 Characterized by bleeding tendency &
increased clotting time.
 Hemoplilia A – 83% cases
* FactorVIII (Classic Hemophilia)
 Hemophilia B – 15% cases
* Factor IX (Christmas disease)
 Hemophilia C – 2% cases
* Factor XI (PTA deficiency)

14. TESTSTHAT DETECT
DEFECTS INTHP
 Bleeding time
 Capillary fragility test
 Platelet aggregation test
 Platelet adhesiveness test
TESTSTHAT DETECT
DEFECTS IN DHP
 Clotting time
 Prothrombin time
 Prothrombin
consumption time
 Partial thromboplastin
time (PTT)
 Activated partial
thromboplastin time
(aPTT)
 Thrombin time
 Clot retraction time

15.  Time lapse between the skin prick and
arrest of bleeding
 Estimated by Duke’s method & Ivy’s
method
 Normal values
by Duke’s method – 1-6 min.
by Ivy’s method – 3-6 min.
 BT is prolonged in Purpura & normal in
Hemophilia

16.  Time between skin prick & formation of
first fibrin thread
 Estimated by Capillary tube method & Lee-
White method
 Normal values
by capillary tube method is 3-6 min.
by lee-white method is 8-12 min.
 Prolonged in hemophila

17.  Quick’s one stage method
 Commercially available tissue
thromboplastin & CaCl2 is added to
oxalated or citrated plasma – incubated at
37oC
 Normal value is 11-16 sec.
 Extrinsic system is tested here.(no platelets
involved)
 Used to monitor anti-coagulant therapy
 Increased in liver failure, vit K deficiency

18.  Also known as KCCT – Kaolin cephalin
clotting time.
 Detects minute coagulation defects
 Normal is 40 sec.
 Measures intrinsic pathway
 Used to monitor Heparin therapy
 Is prolonged in Hemophilia, vWD

19.  Measures final step in coagulation i.e,
availability of functional fibrinogen
 Normal is 10 sec.
 Is prolonged in hypofibrinogenemia,
dysfibrinogenemia, DIC & hepain therapy.

20.  Measures time needed for contraction of an
undisturbed clot.
 Indicates function & number of platelets
 Normally begins within 2 hours and
completed within 24 hours
 Is retarded in thrombocytopenia
 Clot is small & soft in thromboasthenia