Antiphospholipid syndrome

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}} Antiphospholipid syndrome (or antiphospholipid antibodysyndrome) is a disorder of coagulationwhich causes thrombosisin both arteriesand veins, as well as recurrent miscarriage. It is due to the autoimmuneproduction of antibodiesagainst cell membraneconstituents. It is occasionally referred toas Hughes' syndrome after the rheumatologistDr Graham R.V. Hughes (St. Thomas' Hospital, London, UK).

A very rare form is the catastrophic antiphospholipid syndrome, in which there is rapid organ dysfunction and arterial hypertension. It carries a high mortality.

Signs and symptoms

The presence of antiphospholipid antibodies (APLAs) is suggested by thrombosis (arterialor venous) and recurrent miscarriage (especially in the second trimester, but often earlier). Other common findings, although not part of the classification, are thrombocytopenia(low plateletcount) and livedo reticularis(a skincondition). Many patients report headaches.

APLAs are present in the blood in the context of a number of diseases, most notably systemic lupus erythematosus(SLE). One can only speak of antiphospolipid syndrome when there are no other symptoms of one of these diseases (e.g. arthritissuggestive of SLE). A number of patients with the syndrome (about 10%) will eventually develop SLE, but most never get signs of this disease.

Laboratory

The diagnosis is often entertained in cases of thrombophilia(recurrent thrombosis) or recurrent miscarriage. Tests that are often performed at the same time are a full blood count, liver enzymestudies and renal functionstudies.

Thrombophilia screening can consist of:

• Screening coagulation studies: APTT, PTand TT.
• Further studies for Factor V Leidenvariant and the prothrombin mutation, Factor VIIIlevels, MTHFRmutation.
• Levels of protein C, free and total protein S, Factor VIII, antithrombin, plasminogen, tissue plasminogen activator(TPA) and plasminogen activator inhibitor-1(PAI-1)

Antiphospholipid syndrome is tested for in the laboratoryby using a minimum of two coagulation tests that are phospholipid sensitive. The patient on initial screening will typically have been found to have a prolonged APTT that does not correct in a 80:20 mixture with normal human plasma(50:50 mixes with normal plasma are insensitive to all but the highest antibody levels). The APTT (plus 80:20 mix), dilute Russell viper venom time(DRVVT), the kaolin clotting time(KCT) or dilute thromboplastin time{TDT/DTT) are the prinicipal tests used for the detection of lupus anticoagulant. A further antibody can be detected using an enzyme-linked immunosorbant assay(ELISA) immunological test, which screens for the presence of antibodies to anticardiolipin.

Low platelet countand positivity for antibodies against β₂-glycoprotein or phosphotidylserinemay also be observed in a positive diagnosis.

Diagnosis

The diagnosis is made in case of a clinical event (thrombosis or recurrent miscarriage after 10 weeks gestation) and repeated positive tests of lupus anticoagulant and/or anticardiolipin antibodies performed 6-8 weeks apart. Repeat testing is necessary due to the naturally occurring presence of transient high levels of antiphospholipid antibodies following infection and inflammation. Other antibodies, although implicated, are not yet considered relevant for diagnosis.

Pathogenesis

Antiphospholipid syndrome is an autoimmune disease, in which antibodies react against anionic phospholipidson cell membranes. Being an autoimmune disease, it is more common in women than in men. The exact causeis not known, but activation of the system of coagulation is evident.

Treatment

Often, this disease is treated by giving aspirinto inhibit platelet activation, and/or warfarinas an anticoagulant. The goal of the prophylactictreatment is to maintain the patient's INRbetween 2.0-3.0. It is not usually done in patients who have not had any thrombotic symptoms. During pregnancy, heparinis used instead of warfarin because of warfarin's teratogenicity.

Women with recurrent miscarriage are often advised to take aspirin and to start heparin(or low molecular weight heparin) treatment after missing a period. This is the most effective treatment at the moment.

Further reading

• Triona Holden. "Positive Options for Antiphospholipid Antibody Syndrome" ISBN 0897934091.
• Kay Thackray. Sticky Blood. ISBN 1898030774. A personal account of dealing with the condition.

External link

• APS Foundation of America, Inc.
• APS Friends & Support Forum
• Lupus Patients Understanding & Support
• Hughes syndrome.org
• Women's health
• Association with pregnancy loss

id:Sindrom antibodi antifosfolipid

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Antiphospholipid+syndrome Wikipedia article Antiphospholipid syndrome.