hemorrhagic diseases. lesions of the blood vessels lesions of the blood vessels abnormal platelets...
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• Lesions of the blood vesselsLesions of the blood vessels• Abnormal plateletsAbnormal platelets• Abnormalities in the coagulation cascadeAbnormalities in the coagulation cascade• Combinations of abnormalitiesCombinations of abnormalities
Lesions of the blood vesselsLesions of the blood vessels
• Senile purpuraSenile purpura*hemorrhage in *hemorrhage in
the back of hands and the back of hands and forearms or older forearms or older personspersons
*atrophy of the *atrophy of the vesselsvessels
SCURVY• Vitamin C deficiency
gingival bleeding( ANY mucous membrane)bleeding into musclesbleeding into subcutaneous tissuesbleeding around hair follicles; corkscrew-like hair
• Normal collagen synthesis depends upon the hydroxylation of proline and lysine
• enzymes that catalyze the hydroxylation require ascorbic acid
Thrombocytopenia (low platelets count)
• Petechiae in the skin• Oozing from mucosal membranes• Bleeding within the brain
• Low platelet count• Prolonged bleeding time
Causes of thrombocytopenia
• Drugs, chemicals• Irradiation• Leukemia• Myelophthisis (tumor cells replace normal
bone marrow cells)• Splenic sequestration• Multiple blood transfusions• DIC
Idiopathic thrombocytopenic purpura
• ITP• Antibodies against platelets• Damaged platelets are removes by
macrophages in the spleen• Low platelets• Normal/increased megakaryocytes
Thrombotic thrombocytopenic purpura
• TTP• Hyaline aggregates in small blood vessels• Low platelets• Anemia (abnormal blood vessels trap the RBC)• Renal, CNS abnormalities, fever• Cause: von Willebrand disease, enzyme
deficiency
• Von WIllebrand disease: abnormal platelet adhesion
• Aspirin intake: low TxA2; abnormal platelet aggregation
Abnormalities in the Coagulation cascade
• Bleeding from larger vesselshemarthroses (joints)large hematomas/ ecchymosesextensive bleeding with trauma
Abnormalities in the Coagulation cascade
• Classic hemophilia• Christmas disease• Vitamin K deficiency
Classic hemophilia
• Hemophilia A• Factor VIII deficiency• X-linked • Occurs worldwide• Bleeding into the :
musclesSubcutaneous tissuesJoints
• “royal disease”
Vitamin K deficiency
• Adults: fat malabsorption in diseases of the pancreas or small intestines
• Infants: Hemorrhagic disease of the newborn- intestines have small amounts of bacteria-decrease factors II, VII, IX, X
Von Willebrand disease
• MOST COMMON HEREDITARY BLEEDING DISORDER
• Autosomal dominant• Decreased in vWF: Decrease platelet adhesion
to the injured blood vessel (prolonged bleeding time)
DIC
• Consumption of platelets and coagulation factors II, V, VIII
• Low fibrinogen• Hemorrhage and thrombosis• Anemia• Cause: release of thromboplastin, triggers the
intrinsic pathway of coagulation; increased fibrinolysis
DIC• Obstetric complications
ToxemiaAmniotic fluid embolismretained dead fetusplacental accidents
• Cancer – lung, pancreas, prostate, stomach• Infection – bacteria• Trauma• Immune diseases
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