3. Precipitating cause: if spontaneous indicate severe defect
4. surgery: dental extraction, tonsillectomy, circumcision. Bleeding immediately after surgery indicate defective PLT plug formation. Bleeding after some hours indicate failure of PLT plug stabilisation by fibrin due to coagulation defect.
Clinical Features of Bleeding Disorders Platelet Coagulation disorders fac disorders Site of bleeding Skin Deep in soft tis. Mucous membranes (joints, musc) Petechiae Yes No Ecchymoses (“bruises”) Small, superficial Large, deep Hemarthrosis / muscle bleeding Extremely rare Common Bleeding after cuts & scratches Yes No Bleeding after surgery or trauma Immediate, Delayed1-2 d usually mild often severe
The lifespan of a platelet is 7-10 days and the normal count for all ages is 150000-450000
Once released from the BM young platelets are trapped in the spleen for up to 36 hours before entering the circulation, where they have a primary haemostatic role.
Congenital abnormalities of platelets can be divided into disorders of platelet production and those of platelet function. All are very rare. In general they cause moderate to severe bleeding problems.
Decreased production of platelets due to suppression or failure of the BM is the commonest cause of thrombocytopenia. In aplastic anaemia, leukaemia and marrow infiltration, and after chemotherapy, thrombocytopenia is usually associated with a failure of red and white cell production but may be an isolated finding secondary to drug toxicity (penicillamine, cotrimoxazole), alcohol, or viral
infection (HIV, infectious mononucleosis). Viral infection is the most common cause of mild transient thrombocytopenia
Post-transfusion purpura (PTP) is a rare complication of blood transfusion. It presents with severe thrombocytopenia 7-10 days after the transfusion and usually occurs in multiparous women who are negative for the human platelet antigen 1a (HPA1a).
Antibodies to HPA1a develop, and in some way this alloantibody is responsible for the immune destruction of autologous platelets.
Neonatal alloimmune thrombocytopenia (NAITP) is similar to haemolytic disease of the newborn except that the antigenic stimulus comes from platelet specific antigens rather than red
cell antigens. In 80% of cases the antigen is human platelet antigen 1a, and mothers negative (about 5% of the population) for this antigen form antibodies when sensitised by a fetus positive for the antigen. Fetal platelet destruction results from transplacental passage of these antibodies and severe bleeding, including intracranial haemorrhage, can occur in utero.
Heparin-induced thrombocytopenia (HIT) occurs during unfractionated heparin therapy in up to 5% of patients, but is less frequently associated with low molecular weight heparins. It may become manifest when arterial or venous thrombosis occurs during a fall in the platelet count and is thought to be due to the formation of antibodies to heparin that are bound to platelet factor 4. The immune complexes activate platelets and endothelial cells, resulting in thrombocytopenia and thrombosis coexisting. Heparin-induced thrombocytopenia carries an appreciable mortality risk if the diagnosis is delayed.
2. In adults: prednisolone 1 mg/kg/d for 3-4 wk then gradually tapered over 6-8 wk, relapse may occur on tapering. Platelet recovery occurs within 3 weeks in 2/3 of pts. If platelet count did not increase after 4 weeks of treatment, consider splenectomy
PLT transfusion and IVIg 1 g/kg IV daily 1–2 days, indicated in life-threatening bleeding. If the pt has two relapses , splenectomy is indicated, which is curative in 70% of patients, in the remainder the aim is to keep the patient free of symptoms rather than to raise level of PLT( e.g 5mg/d of prednisolone may be sufficient)
Factor VIII is synthesized mainly by liver , but also by spleen, kidney, and placenta, carried by vWF, half-life in plasma is 12hr.
It is X-linked recessive and affects about 1/10000, thus all daughters of hemophiliacs are carriers and 50% of sisters are carriers. If a carrier has a son, he has 50% chance of having hemophilia and a daughter has 50% chance of being a carrier
microangiopathic hemolytic anemia, thrombocytopenia, bleeding, thrombosis, ischemia. ↑ INR, ↑ PTT, ↓ fibrinogen (although it can be normal or even elevated), ↓ factor VIII (in contrast to liver diseases, which have normal factor VIII). Schistocytes on peripheral smear
treat underlying cause and complications (hypoxia, dehydration, acidosis, acute renal failure). Replete coagulation factors if bleeding (FFP 2 U, cryoprecipitate 10 U). Anticoagulation if thrombosis (consider IV heparin)
Management of Hemostatic Defects in Liver Disease