All of the following are true about lupus anticoagulant except -
Ans. is 'c' i.e., Recurrent bleeding episodes Make it clear once and for always."Despite having been named lupus "anticoagulant" lupus anticoagulation syndrome does not present with bleedingLupus anticoagulant is characterized by the presence of circulating lupus anticoagulant in the body but itsPredominant symptom is thrombosis.The circulating anticoagulants do not exert any anticoagulant effect in vivo instead they act in vitro. The main symptoms of lupus anticoagulant is thrombosis. The thrombotic manifestations are entirely independent of anticoagulant or antiphospholipid antibodies. The reason for thrombosis is not quite clear but it has no relation with circulating anticoagulants. The thrombotic episodes are life threatening.Bleeding episodes in lupus anticoagulant - Bleeding may occur with lupus anticoagulant but is quite rare and do not lead to life threatening hemorrhage.According to William's hematology - Although thrombocytopenia is a common finding in APS, bleeding complications, are rare even with severe thrombocytopenia bleeding in an antiphospholipid antibody syndrome should trigger evaluation for the presence of antiprothrombin antibodies and other disorders that may affect hemostasis such as DIC and Uremia.Thrombocytopenia due to antiplatelet antibodies is usually mild to moderate without bleeding (Tejinder Singh hematology Atlas)* Many cases of lupus anticoagulant can be "asymptomatic" too.Antiphospholipid Antibody SyndromePatients with antiphospholipid antibody syndrome fall into two categories.Secondary antiphospholipid antibody syndromeIn this cases antiphospholipid antibody syndrome is associated with an autoimmune disease usuallySLE.Primary antiphospholipid antibody syndrome * In these cases there is no evidence of other autoimmune disease, the patient exhibit only the manifestations of antiphospholipid antibody syndrome.Lupus anticoagulant increases the PIT but not the PT.Lupus anticoagulant syndrome is characterized by the presence of circulating anticoagulants or the antiphospholipid antibodies. But the predominant symptom of antiphospholipid antibody syndrome is thrombosis.The question which immediately comes to mind is, how a patient with circulating anticoagulant has thrombosis as its predominant manifestation??The point to emphasize here is that circulating anticoagulants are not responsible for any clinical syndrome in case of antiphospholipid antibody syndrome. These antibodies are unable to exert any effect in circulation. They act as anticoagulants only in invitro not invivo.The thrombotic manifestations are entirely independent of anticoagulant or antiphospholipid antibodies. The reason for thrombosis is not quiet clear but it has no relation with circulating anticoagulants.The effect of circulating anticoagulant is seen only during laboratory test where their presence increase thePTT.The anticoagulants exert this effect by acting against phospholipids.These anionic phospholipids are present on the plasma membranes of the activated platelets, which form platelet plugs at the site of injury. The coagulation factors assemble on the surface of activated platelets and thus becomes concentrated at sites of vascular injury. The circulating anticoagulants acts by blocking these phospholipids.NOW,Two questions crops up,Why do the circulating anticoagulants do not exert their effect in vivo?"And why do these anticoagulants affect only PTT and not PT."ExplanationWhile performing PTT patient is given calcium, partial thromboplastin along with an intrinsic pathway activator.Partial thromboplastin contains the phospholipid needed for coagulation.If the patients plasma, contain antiphospholipid antibodies, it will inhibit the phospholipids present in the partial thromboplastin. Since the partial thromboplastin has limited phospholipids the coagulation gets inhibited by the anticoagulants and thus the PTT increases.On the other hand in the body there is abundant supply of phospholipids from the platelets therefore the antiphospholipid antibodies are not able to affect the coagulation. Platelets continuously replenish the phospholipids.While performing test for prothrombin time (PT) patient is given tissue factor i.e. thromboplastin.Thromboplastin contains abundant supply of phospholipid so the circulating (plasma) anticoagulants are not able to exert their effect on it, and thus PT remains normalCoagulation tests in lupus anticoagulant. PTTQ-Prolonged. PTQ-Normal. BTQ-Normal* Fibrinogen Q-Normal
Prolongation of only aPTT
Recurrent second trimester abortion
Recurrent bleeding episodes
Can be associated without any clinical symptoms
Bleeding and Thrombotic Disorders