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Antiphospholipid syndrome

Antiphospholipid syndrome ( APS ) is a systemic autoimmune disorder with a wide range of vascular and obstetric manifestations associated with thrombotic and inflammatory mechanisms orchestrated by antiphospholipid ( aPL ) antibodies
 ( Tektonidou MG et al EULAR recommendations for the management of antiphospholipid syndrome in adults 2019 )


a rare disease ( estimated prevalence 5 cases per 1000,000 people / year ) most common cause of acquired thrombophilia , in people < 50 can be responsible for 
○ 15 % to 20 % of all DVT episodes
○ 1/3rd of new CVA cases
○ recurrent fetal loss ( e,g 3 or + losses < 10 wks gestation , 1 or + losses ≥ 10 wks gestation , pre-term birth < 34 wks due to eclampsia , pre-eclampsia or placental insufficiency ) vascular thrombosis can be arterial , venous or small vessel , can affect any organ or tissue but the most common sites
are of venous & arterial thrombosis are the lower limbs and the cerebral arterial circulation Various diagnostic criteria exist as The International consensus ( revised Sapporo ) criteria for diagnosis for diagnosis pf obstetric antiphospholipid syndrome patients may also develop less frequent other organ involvement related to APS , referred as non-criterion manifestations as livedo-reticularis , thrombocytopenia ,nephropathy ,heart valve disease , migraine convulsions , superficial venous thrombosis


Multisystem autoimmune disorder
 presence of persistent antiphospholipid antibodies 
( APLA ) APLA are a heterogenous group of antibodies that have a clear associations with thrombosis and pregnancy morbidity low titer aPL’s can be seen in upto 
10 % of healthy individuals


aPL antibodies can 
be 1 of 3 types ( APL profile ) 
 lupus anticoagulant anticardiolipin antibodies antibeta2 glycoprotein antibodies

○ their primary targets are phospholipid binding proteins
○ presence of aPL in asymptomatic individuals or patients with SLE does not confirm diagnosis but can be associated with increased risk of thrombosis or pregnancy morbidiy


APS can be
 found in patients having neither clinical nor lab evidence of another definable condition ( primary APS )
 in association with other diseases mainly SLE ( 7-15 % of pts with SLE ) , occasionally with other autoimmune conditions , infections , drugs & malignancies


aPL type , presence of multiple ( double or triple ) versus single aPL type , their titre (moderate-high titre versus low ) and the persistence of aPL positivity in repeated measurements ) constitute aPL profile aPL profile – determines the risk of thrombotic and obstetric events and consequently the intensity of treatment accordingly medium-high aPL titres , high-risk aPL profile and low-risk aPL profile.


Main differentials are hereditary or acquired thrombophilias Clinical practice can vary substantially as APS is a rare disorder , knowledge about diagnosis / classification , clinical spectrum and management is constantly evolving Catastrophic APS ( CAPS ) – severe spectrum of APS characterized by multiple thromboses in > 3 sites ( often due to anticoagulation discontinuation in people with established APS diagnosis , infections & surgical procedures )


DVT or PE in young people or those without risk factors thrombosis in atypical sites or multiple thromboses CVA or TIA in a patient aged < 50 any thrombosis in a patient with SLE or other autoimmune disease recurrent abortions or associated obstetric complications unexplained thrombocytopenia presence of livedo reticularis racemosa


Primary / Secondary thromboprophylaxis Obstetric APS management Emerging treatment with medications other than anticoagulant.


APS Support UK – helping people with APS , section on GP teaching

American College of Rhematology on APS

APS in pregnancy -printable 8 page booklet from East and North Hertfordshire NHS Trust

Sparrow Org ( Michigan ) useful plain language section on APS




  1. Tektonidou MGAndreoli LLimper M, et al EULAR recommendations for the management of antiphospholipid syndrome in adults
  2. Lopes, Michelle Remião Ugolini et al. Update on antiphospholipid antibody syndrome. Revista da Associação Médica Brasileira [online]. 2017, v. 63, n. 11 [Accessed 23 April 2022] , pp. 994-999. Available from: <>. ISSN 1806-9282.
  3. Bustamante JG, Goyal A, Singhal M. Antiphospholipid Syndrome. [Updated 2021 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
  4. Jose A. Gómez-Puerta, Ricard Cervera, Diagnosis and classification of the antiphospholipid syndrome, Journal of Autoimmunity, Volumes 48–49, 2014, Pages 20-25,
    ISSN 0896-8411,



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