Haematology

Haemostasis

The involvement of blood vessels, platelets and blood coagulation in haemostasis

Vascular bleeding disorders: .The underlying abnormalities are either in the vessels themselves perivascular connective tissue. Each could be Inherited Acquired

Inherited vascular disorders Hereditary haemorrhagic telangiectasia autosomal dominant trait. There are dilated microvascular swellings appear during childhood and become more numerous in adult life. These telangiectasia develop in the skin, mucous membranes and internal organs

Ehlers-Danlos syndrome hereditary collagen abnormalities with purpura resulting from defective platelet aggregation hyperextensibility of joints and hyperelastic friable skin

Acquired vascular defect Simple easy bruising Purpura associated with infections Senile purpra Scurvy The Henoch-Schonlein syndrome Steroid purpura

b a

Henoch –Sconlein syndrome immune complex (typeIII) hypersensitivity reaction usually found in children often following acute infection The characteristic purpuric rash accompanied by localized edema & itching is often most prominent on the buttocks &extensor surfaces of lower legs & elbows Painful joint swelling, haematuria & abdominal pain may also occur.

Thrombocytopenia

3-Abnormal distribution of platelets *splenomegaly 4-Dilutional loss *Massive transfusion of stored blood

Hereditary disorders Acquired disorders Antiplatelet drugs Uraemia Thrombasthenia (Glanzmann's disease) Bernard-Soulier syndrome Storage pool diseases Acquired disorders Antiplatelet drugs Hyperglobulinaemia Myeloproliferative and myelodysplastic Disorders Uraemia Heparin, dextrans, alcohol and radiographic contrast

Assessment of Coagulation 1.Clinical assessment. 2.Labroratory assessment.

Laboratory assessment of Coagulation: Bleeding time: Platelet counts: Prothrombin time (PT): Partial thromboplastin time (PTT): Thrombin time (TT):

Case A 5 yr old boy presents with a haemarthrosis of the right knee. Coagulation studies show normal PT ,normal bleeding time,normal TT, prolonged APTT . Explain the coagulatin defect?

The defect is in the intrinsic pathway . Haemophillia A or Haemophillia B Factor assay.

Haematoma

DIC

Lab. Findings: 1 .The platelet count is low. 2. Fibrinogen concentration low. 3 .The thrombin time is prolonged. 4 .High levels of fibrin degradation products such as D -dimers are found in serum and urine. 5. The PT and APTT are prolonged .  6. bleeding time is prolonged.

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