Blood Anti-coagulants & Hemorrhagic Disorders Lecture PDF

 Anti-coagulants & Hemorrhagic Disorders By Dr Eman Hamdy Basha Lecturer of physiology Smile and Go on  Anti-coagulants  Definition: They are substances which prevent or postpone coagulation of blood.  Types of anticoagulants  in vivo (prevent blood coagu...

 Anti-coagulants & Hemorrhagic Disorders By Dr Eman Hamdy Basha Lecturer of physiology Smile and Go on  Anti-coagulants  Definition: They are substances which prevent or postpone coagulation of blood.  Types of anticoagulants  in vivo (prevent blood coagulation inside the body)  in vitro (prevent blood coagulation outside the body)  Anti-coagulants  In vitro (prevent blood coagulation outside the body) It means prevention of blood coagulation outside the body. It is done by: (1)Cold: Delays clotting. (2)Collecting the blood in smooth paraffin or silicon lined vessels to prevent activation of F XII. 3) Decalcifying agents: a) K Oxalate: Precipitates Ca oxalate. b) Na citrate: combines with Ca++ to form unionized Ca compound. c) EDTA: “Ethyl diamine tetra acetic acid”  it is chelating calcium ions. 4) Heparin. Anti-coagulants- Invivo  Heparin Dicoumarol 1. Origin Animal in origin Plant in origin 2. Latent period After few minutes After two days of action 3. Duration of 4-6 hours Few days action 4. Route of I.V. or I.M. injection Oral administration 5. Mechanisms - Anti-prothrombin Competitive of action activator inhibition of vitamin - Anti-prothrombin. K - Anti-thrombin. (i.e. anti F II,VII, IX and X). 6. Site of action In vivo, in vitro In vivo only 8. Anti-dote Protamin sulphate Vitamin K.  Hemorrhagic Disorders  Definition: They are conditions that cause excessive bleeding in human beings  Definition: 1-Purpura It is a bleeding disease characterized by occurrence of spontaneous punctuate hemorrhages usually beneath the skin and mucous membrane (which is called petechiae). These petechiae appear as purplish spots.  Types and causes: 1-Purpura Purpura is classified into different types depending on the cause as following: 1. Thrombocytopenic purpura:  It is due to decrease in the number of platelets (below 50000/mm3).  It may occurs due to: a) Decrease platelet production due to  damage of bone marrow.  Or b) Increase platelet destruction as in (hyperspleenism). 2) Thromboesthenic purpura: It is due to abnormal platelets in circulation. The platelets count is normal. 3) Idiopathic thrombocytopenic purpura:  It is due to unknown cause.  Characters: a) Bleeding time is prolonged b) Coagulation time is normal.  2-Vitamin K-Deficiency  Causes: 1. Failure of absorption of vitamin K. e.g. Intestinal diseases 2. Failure of vitamin K synthesis in the intestine by intestinal bacteria due to: i) Prolonged use of antibiotics. ii) Newly born infant. 3. Dicoumarol toxicity. Intoxications by oral anticoagulants (dicumarol), leads to competitive inhibition to vitamin K. 4. Severe lack of vitamin K in diet.  Effects of vitamin K deficiency: Bleeding tendency due to inhibition of formation of factors II, VII, IX, X and protein C&S in the liver.  3- Hemophilia  Definition: It is a sex–linked inherited bleeding disease.  Characters: It is transmitted by females to the male infant. The females don’t suffer so it is sex–linked. The injured vessel causes severe hemorrhage for long time.  Coagulation time is prolonged. Bleeding time is normal.  Causes: Hemophilia occurs due to hereditary deficiency of coagulation factors  e.g. F VIII, IX and factor XI which causes bleeding tendencies.  2- Hemophilia Types of hemophilia: The 3 common types are: 1- Hemophilia A “Classic Hemophilia”: It is due to deficiency of factor VIII. It is the commonest type 2-Hemophilia B “Christmas disease”: It is due to deficiency of factor IX. 3-Hemophilia C: It is due to deficiency of factor XI. It is the rarest type.  Hemophilia Purpura 1- Heredity Inherited Not inherited 2- Affected sex Male only Both male & female 3- Cause Lack of clotting Lack of platelets number factors VIII, IX or XI or function 4- Types 1) Hemophilia (A) 1) Thrombocytopenic 2) Hemophilia (B) 2) Thromoasthenic. 3) Hemophilia (C) 3) Idiopathic purpura 5- Bleeding time Normal Prolonged 6- Coagulation time Prolonged Normal  Thrombocytes (blood platelets) Normal count: The number of platelets is about 250.000/mm3. They are manufactured in bone marrow. Function:  They play important role in haemostasis as following:  Local vasoconstriction of the injured vessels due to release of serotonin and thromboxane A2. 1) Platelet plug formation. 2) Blood coagulation due to release of platelets phospholipids. 3) Clot retraction due to release of retractozyme. 4) Repair of injured blood vessel by PDGF. Smile and Go on