#132 Antiphospholipid Syndrome Flashcards
What % of people with antiphospholipid syndrome are female?
70%
What is the role of beta2-glycoprotein I?
Regulatory role in coagulation, fibrinolysis, and other physiologic systems
What medical/obstetrical problems are associated with antiphospholipids antibodies?
Arterial thrombosis, venous thrombosis, autoimmune thrombocytopenia, fetal loss, preeclampsia, IUGR, placental insufficiency, preterm delivery, hemolytic anemia, amaurosis fugax, livedo reticularis, SLE, false-positive RPR
What antiphospholipid antibodies contribute to the diagnosis of antiphospholipid syndrome?
- Lupus anticoagulant
- Anticardiolipin
- anti-beta2-glycoprotein I
Which antibody associated with antiphospholipid syndrome is most specific?
Lupus anticoagulant. But it is less sensitive than the other two.
Do you need all three antibodies to be diagnosed with antiphospholipid syndrome?
No.
What are laboratory criteria for diagnosis of antiphospholipid syndrome?
- Lupus anticoagulant present in plasma on two or more occasions at least 12 weeks apart (when no on anticoagulants)
- Anticardiolipin antibody IgG and/or IgM >99%tile on two or more occasions at least 12wks apart
- Anti-beta2-glycoprotein I IgG and/or IgM >99%tile on two or more occasions at least 12wks apart
How do you screen for lupus anticoagulant?
Combination of sensitive clotting assays, such as lupus anticoagulant-sensitive activated PTT and dilute Russell’s viper venom time
Which isotypes of anticardiolipin antibodies matter?
IgG and IgM. Clinical relevance of IgA is uncertain
What test is used to measure anticardiolipin antibodies?
Enzyme-linked immunosorbent assay
What test is used to measure anti-beta2-glycoprotein I?
Enzyme-linked immunosorbent assay
What is considered a positive anti-beta2-glycoprotein antibody test?
> 99th percentile
What percentage of patients with venous thrombosis will test positive for lupus anticoagulant antibodies?
2%
What is the risk of thrombosis during pregnancy or puerperium in women with antiphospholipid syndrome?
5-12%
What is the most common consequence of an arterial occlusion?
Stroke
What percentage of individuals <50yo (otherwise healthy) with stroke have antiphospholipid antibodies?
4-6%
What percentage of individuals with antiphospholipid syndome will have autoimmune thrombocytopenia?
40-50%
Is thombocytopenia from antiphospholipid syndrome vs immune thrombocytopenic purpura treated differently?
No, same therapy. steroids. immune globulin.
What is the definition of the fetal period?
Greater than 10wks
What % of pregnancy losses occur during the fetal period (>10wk) in women with antiphospholipid antibodies vs general population?
50% vs 10%
What % of women with antiphospholipid antibodies had at least one fetal death compared to those without antibodies?
84% vs 24%
What percentage of women with recurrent pregnancy loss test positive for antiphospholipid antibodies?
5-20%. Not known if these cases would meet current international criteria for APLS
What percentage of women with preeclampsia test positive for antiphospholipid antibodies?
11-17%
What percentage of pregnancies in women with APLS are IUGR?
15-30%
What are clinical criteria for diagnosis of APLS?
- vascular thrombosis: one or more clinical episodes of arterial, venous, or small vessel thrombosis or
- Pregnancy morbidity:
- one or more unexplained deaths of normal fetus at or beyond 10wks, or
- one or more premature births of normal neonate before 34wks d/t SPEC, eclampsia, placental insufficiency, or
- three or more unexplained consecutive spontaneous pregnancy losses before 10th week
How should a women with APLS w/ hx thrombosis be managed during pregnancy?
Prophylactic anticoagulation with heparin throughout pregnancy and 6wks postpartum. Many people add ASA, but benefit is unknown
How should you treat women with APLS without hx of thrombosis?
Clinical surveillance or prophylactic heparin antepartum in addition to 6wk postpartum
How should women with APLS and recurrent pregnancy loss be managed?
Prophylactic heparin and low-dose ASA. May reduce pregnancy loss by 50%
Is antepartum surveillance (fetal testing) recommended for patients with APLS?
Many experts recommend serial ultrasound assessment and antepartum testing in 3rd trimester. Data insufficient to support or refute specific practice.
Is APLS a contraindication to estrogen-containing contraceptives?
Yes.
