Dr Ambika Jawalkar

I. Platelet disorders

II. Coagulation disorders/defective coagulation mechanism

III. Vascular disorders (Non-thrombocytopenic purpura)

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

Deficiency of clotting factors* Hemophilia

Vitamin K deficiency Anticoagulant overdose Disseminated intravascular clotting (DIC)

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

Group of bleeding disorders Characteristic features are,

*purple-colored petechial haemorrhages*bruises in the skin

CAUSES:1. Platelet disorders

Thrombocytopenic purpura – primary, secondary

Thrombosthenic purpura – vWD1. Vascular disorders – non-

thrombocytopenic purpura

“group of disorders occouring due to heriditary deficiency of coagulation”

Characterized by bleeding tendency & increased clotting time.

Hemoplilia A – 83% cases* Factor VIII (Classic Hemophilia)

Hemophilia B – 15% cases* Factor IX (Christmas disease)

Hemophilia C – 2% cases* Factor XI (PTA deficiency)

TESTS THAT DETECT DEFECTS IN THP

Bleeding time Capillary fragility test Platelet aggregation test Platelet adhesiveness test

TESTS THAT 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

Time lapse between the skin prick and arrest of bleeding

Estimated by Duke’s method & Ivy’s method

Normal valuesby Duke’s method – 1-6 min.by Ivy’s method – 3-6 min.

BT is prolonged in Purpura & normal in Hemophilia

Time between skin prick & formation of first fibrin thread

Estimated by Capillary tube method & Lee-White method

Normal valuesby capillary tube method is 3-6 min.by lee-white method is 8-12 min.

Prolonged in hemophila

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

Also known as KCCT – Kaolin cephalinclotting time.

Detects minute coagulation defects Normal is 40 sec. Measures intrinsic pathway Used to monitor Heparin therapy Is prolonged in Hemophilia, vWD

Measures final step in coagulation i.e, availability of functional fibrinogen

Normal is 10 sec. Is prolonged in hypofibrinogenemia,

dysfibrinogenemia, DIC & hepain therapy.

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