17. Classification of bleeding disorders. DIC - Syndrome

Essay 17- Classification of bleeding disorders. DIC - syndrome

• What is hemorrhagic diathesis?
• Refers to an increased susceptibility to bleeding or bruising.
• It can occur as a result of a wide variety of underlying disorders

Classification

• Platelet disorders
• Thrombocytopenia
• Refers to decrease in number of circulating platelets
• Normal number of thrombocytes is 140-400×10^9/L
• Causes of thrombocytopoenia
• Impaired production- bone marrow dysfunction, liver dysfunction, B12 or folate deficiency, viral illness
• Increased destruction- autoimmune disorders, acute ITD, thombocytopenic purpura, drugs
• Increased losses- sequestration (normally, 1/3 of platelets are sequestered, but in splenomegaly upto 90% can be trapped
• Due to portal hypertension
• HIT (heparin induced thrombocytopenia)
• Seen in patients with unfractioned heparin (larger structure)
• Unfractioned heparin has lipopolysaccharides in its structure
• Platelet factor 4 is a protein that binds to lipopolysaccharide to create a large molecule that is recognised as an antigen
• This results in the production of auto antibodies
• Autoantibodies act as a pro-aggregant factor and bind cell platelets resulting in their lysis
• HUS (hemolytic uremic syndrome)
• This is triggered by a type of E.coli which acquires the shiga toxin
• The shiga toxin causes Neu in glomeruli to release proteolytic enzymes which destroy PLT and RBC
• Characterized with hemolysis, platelet destruction, acute kidney injury which leads to retention of urea.
• Thrombocytic thrombocytopenic purpura (TTP)
• Combination of thrombocytopenia, hemolytic anemia, acute renal failure, fever, and neurologic abnormalities
• The onset is abrupt
• Rare disorder occurring in adult women
• Caused by ADAMTS-13- proteolytic enzyme cleaves vWF and releases them
• If patient lacks this- thrombus formation can occur
• Caused by widespread endothelial damage and activation of intravascular thrombosis
• Similar to DIC but does not involve the clotting system
• Widespread vascular occlusions consist of thrombi in arterioles and capillaries of many organs
• Erythrocytes become fragmented as they circulate through the partly occluded vessels and cause the hemolytic anemia and jaundice
• Clinical manifestations include purpura, petechiae, and vaginal bleeding and neurologic symptoms (headaches, seizures, altered mental state)
• Treatment includes plasmapheresis, a procedure that involves removal of plasma from withdrawn blood and replacement with fresh-frozen plasma
• Idiopathic thrombocytopenic purpura
• Autoimmune disorder that results in platelet antibody formation and excess destruction of platelets
• IgG binds to two membrane glycoproteins while in circulation
• Platelets are destroyed in the spleen and liver
• Occurs in young children and usually follows a viral infection
• It is characterized by sudden onset of petechiae and purpura and is a self-limited disorder with no treatment