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| {{Infobox medical condition (new) | | {{Short description|A type of antibody associated with increased risk of thrombosis}} |
| | name = Lupus anticoagulant | |
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| | synonyms = Lupus antibody, LA, LAC, lupus inhibitors
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| '''Lupus anticoagulant''' is an [[immunoglobulin]]<ref name="JoussenGardner2007">{{cite book|author1=Antonia Joussen|author2=T.W. Gardner|author3=B. Kirchhof|title=Retinal Vascular Disease|url=https://books.google.com/books?id=XBiCIhGenxsC&pg=PA430|accessdate=29 June 2010|date=23 October 2007|publisher=Springer|isbn=978-3-540-29541-9|pages=430–}}</ref> that binds to [[phospholipid]]s and [[protein]]s associated with the cell membrane. Its name is a [[misnomer]], as it is actually a [[thrombosis|prothrombotic]] antibody. Lupus anticoagulant in living systems cause an increase in inappropriate blood clotting. The name derives from their properties in vitro, as these antibodies increase laboratory coagulation tests such as the [[Partial thromboplastin time|aPTT]]. Investigators speculate that the antibodies interfere with phospholipids used to induce in vitro coagulation. In vivo, the antibodies are thought to interact with platelet membrane phospholipids, increasing adhesion and aggregation of platelets, which accounts for the in vivo prothrombotic characteristics.
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| | '''Lupus anticoagulant''' is an [[autoantibody]] associated with an increased risk of [[thrombosis]], or blood clot formation. Despite its name, lupus anticoagulant is not related to [[lupus erythematosus]] and does not cause bleeding. Instead, it interferes with the normal clotting process, leading to a paradoxical increase in clotting risk. |
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| The condition was first described by hematologist [[C. Lockard Conley]].<ref>{{cite journal|last=Conley|first=C. Lockard|year=1952|title=A hemorrhagic disorder caused by circulating anticoagulant in patients with disseminated lupus erythematosus|journal=Journal of Clinical Investigation|volume=31|pages=621–622|doi=10.1172/JCI102648|pmc=436459|pmid=14938435}}</ref><ref name="Lock">{{cite news|url=http://www.hopkinsmedicine.org/hmn/S06/conley.cfm|title=Lock Conley looks back and blushes|date=Spring–Summer 2006|work=Hopkins Medicine|accessdate=5 December 2013|archive-url=https://web.archive.org/web/20130621180626/http://www.hopkinsmedicine.org/hmn/S06/conley.cfm|archive-date=21 June 2013|url-status=dead}}</ref>
| | ==Pathophysiology== |
| | Lupus anticoagulant is a type of [[antiphospholipid antibody]] that targets [[phospholipids]] and [[phospholipid-binding proteins]] in the cell membrane. These antibodies interfere with the coagulation cascade, particularly affecting the [[prothrombin]] and [[activated partial thromboplastin time]] (aPTT) tests, which are used to assess blood clotting. The presence of lupus anticoagulant prolongs these clotting times in vitro, but in vivo, it predisposes individuals to thrombosis. |
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| ==Terminology== | | ==Clinical Significance== |
| Both words in the term "lupus anticoagulant" can be misleading:
| | Lupus anticoagulant is a key component of the [[antiphospholipid syndrome]] (APS), a disorder characterized by recurrent [[venous]] or [[arterial thrombosis]] and [[pregnancy complications]] such as [[recurrent miscarriage]]. Patients with lupus anticoagulant may experience [[deep vein thrombosis]], [[pulmonary embolism]], [[stroke]], or other thrombotic events. |
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| * Most patients with a lupus anticoagulant do not actually have [[lupus erythematosus]], and only a small proportion will proceed to develop this disease (which causes joint pains, skin problems and [[kidney failure]], amongst other complications). People with lupus erythematosus are more likely to develop a lupus anticoagulant than the general population.
| | ==Diagnosis== |
| * The term "anticoagulant" accurately describes its function [[in vitro]]. However [[in vivo]], it functions as a ''[[procoagulant]]''.<ref name="urlUntitled Document">{{cite web |url=http://dermatology.wustl.edu/dermsub/caseofmonth/11-2005a.html |title=wustl.edu |work= |accessdate=2009-02-17 |archive-url=https://web.archive.org/web/20080821152206/http://dermatology.wustl.edu/dermsub/caseofmonth/11-2005a.html |archive-date=2008-08-21 |url-status=dead }}</ref>
| | The diagnosis of lupus anticoagulant involves a series of blood tests. Initial screening includes the [[activated partial thromboplastin time]] (aPTT) and the [[dilute Russell's viper venom time]] (dRVVT). If these tests are prolonged, further confirmatory tests are performed, such as mixing studies and phospholipid neutralization procedures, to confirm the presence of lupus anticoagulant. |
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| == Workup == | | ==Management== |
| The presence of prolonged clotting times on a routine plasma test often triggers functional testing of the blood clotting function, as well as [[serological]] testing to identify common autoantibodies such as [[antiphospholipid antibodies]]. These antibodies tend to delay [[in-vitro]] [[coagulation]] in phospholipid-dependent laboratory tests such as the [[partial thromboplastin time]].
| | Management of patients with lupus anticoagulant focuses on reducing the risk of thrombosis. This often involves the use of [[anticoagulant]] medications such as [[warfarin]] or [[heparin]]. In patients with antiphospholipid syndrome, long-term anticoagulation may be necessary. During pregnancy, low-dose [[aspirin]] and [[heparin]] are commonly used to prevent complications. |
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| The initial workup of a prolonged PTT is a [[mixing test]] whereby the patient's plasma is mixed with normal pooled plasma and the clotting is reassessed. If a clotting inhibitor such as a lupus anticoagulant is present, the inhibitor will interact with the normal pooled plasma and the clotting time will remain abnormal. However, if the clotting time of the mixed plasma corrects towards normal, the presence of an inhibitor such as the lupus anticoagulant is excluded, and instead a deficient quantity of clotting factor (that is replenished by the normal plasma) is likely.
| | ==Related pages== |
| | | * [[Antiphospholipid syndrome]] |
| If the mixing test indicates an inhibitor, diagnosis of a lupus anticoagulant is then confirmed with prolonged [[phospholipid]]-sensitive functional clotting testing, such as the [[dilute Russell's viper venom time]], or the [[Kaolin clotting time]]. As a further confirmation, a second test with the addition of excess phospholipid will correct the prolongation (conceptually known as "phospholipid neutralization"), confirming the diagnosis of a lupus anticoagulant.
| | * [[Thrombosis]] |
| | | * [[Autoantibody]] |
| ==Treatment== | | * [[Coagulation]] |
| Treatment for a lupus anticoagulant is usually undertaken in the context of documented [[thrombosis]], such as extremity phlebitis or dural sinus vein thrombosis. Patients with a well-documented (i.e., present at least twice) lupus anticoagulant and a history of [[thrombosis]] should be considered candidates for indefinite treatment with [[anticoagulants]]. Patients with no history of [[thrombosis]] and a lupus anticoagulant should probably be observed. Current evidence suggests that the risk of recurrent [[thrombosis]] in patients with an [[antiphospholipid antibody]] is enhanced whether that antibody is measured on serological testing or functional testing. The [[Sapporo criteria]] specify that both serological and functional tests must be positive to diagnose the [[antiphospholipid antibody syndrome]].<ref name="pmid1782567">{{cite journal |vauthors=Viard JP, Amoura Z, Bach JF | title = [Anti-beta 2 glycoprotein I antibodies in systemic lupus erythematosus: a marker of thrombosis associated with a circulating anticoagulant] | language = French | journal = Comptes Rendus de l'Académie des Sciences, Série III | volume = 313 | issue = 13 | pages = 607–12 | year = 1991 | pmid = 1782567 | doi = }}</ref>
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| Miscarriages may be more prevalent in patients with a lupus anticoagulant. Some of these miscarriages may ''potentially'' be prevented with the administration of aspirin and unfractionated heparin. The Cochrane Database of Systematic Reviews provide a deeper understanding on the subject.<ref name="pmid15846641">{{cite journal|last=Empson|first=M|author2=Lassere, M |author3=Craig, J |author4= Scott, J |title=Prevention of recurrent miscarriage for women with antiphospholipid antibody or lupus anticoagulant.|journal=The Cochrane Database of Systematic Reviews|date=Apr 18, 2005|issue=2|pages=CD002859|pmid=15846641|doi=10.1002/14651858.CD002859.pub2|url=http://apps.who.int/rhl/reviews/CD002859.pdf}}</ref>
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| Thrombosis is treated with [[anticoagulant]]s ([[Low molecular weight heparin|LMWHs]] and [[warfarin]]).<ref>{{cite journal |vauthors=Dolitzky M, Inbal A, Segal Y, Weiss A, Brenner B, Carp H |title=A randomized study of thromboprophylaxis in women with unexplained consecutive recurrent miscarriages |journal=Fertil Steril |volume=86 |issue=2 |pages=362–6 |year=2006 |pmid=16769056 |doi=10.1016/j.fertnstert.2005.12.068}}</ref>
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| ==References==
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| == External links ==
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| {{Medical resources
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| | DiseasesDB = 775
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| | ICD10 =
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| | ICD9 = {{ICD9|289.81}}
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| | OMIM = 107320
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| | MeshID = D016682
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| {{Autoantibodies}}
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| | [[Category:Hematology]] |
| | [[Category:Autoimmune diseases]] |
| [[Category:Coagulation system]] | | [[Category:Coagulation system]] |
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A type of antibody associated with increased risk of thrombosis
Lupus anticoagulant is an autoantibody associated with an increased risk of thrombosis, or blood clot formation. Despite its name, lupus anticoagulant is not related to lupus erythematosus and does not cause bleeding. Instead, it interferes with the normal clotting process, leading to a paradoxical increase in clotting risk.
Pathophysiology
Lupus anticoagulant is a type of antiphospholipid antibody that targets phospholipids and phospholipid-binding proteins in the cell membrane. These antibodies interfere with the coagulation cascade, particularly affecting the prothrombin and activated partial thromboplastin time (aPTT) tests, which are used to assess blood clotting. The presence of lupus anticoagulant prolongs these clotting times in vitro, but in vivo, it predisposes individuals to thrombosis.
Clinical Significance
Lupus anticoagulant is a key component of the antiphospholipid syndrome (APS), a disorder characterized by recurrent venous or arterial thrombosis and pregnancy complications such as recurrent miscarriage. Patients with lupus anticoagulant may experience deep vein thrombosis, pulmonary embolism, stroke, or other thrombotic events.
Diagnosis
The diagnosis of lupus anticoagulant involves a series of blood tests. Initial screening includes the activated partial thromboplastin time (aPTT) and the dilute Russell's viper venom time (dRVVT). If these tests are prolonged, further confirmatory tests are performed, such as mixing studies and phospholipid neutralization procedures, to confirm the presence of lupus anticoagulant.
Management
Management of patients with lupus anticoagulant focuses on reducing the risk of thrombosis. This often involves the use of anticoagulant medications such as warfarin or heparin. In patients with antiphospholipid syndrome, long-term anticoagulation may be necessary. During pregnancy, low-dose aspirin and heparin are commonly used to prevent complications.
Related pages
