Antiphospholipid syndrome

Question 1

What is antiphospholipid syndrome?

Answer 1

An autoimmune disorder in which antibodies are targeted against phospholipid binding proteins (phospholipids are major component of cell membranes)

Question 2

What percentage of women with recurrent miscarriage have antiphospholipid syndrome?

Answer 2

15%

Question 3

Describe the action of the antibodies in vitro

Answer 3

Inhibit assembly of phospholipid complexes and inhibit coagulation

Question 4

Describe the action of the antibodies in vivo

Answer 4

Induce a procoagulant state

Question 5

What are the obstetric complications of antiphospholipid syndrome due to?

Answer 5

Inhibition of trophoblastic function and differentiation
Activation of the complement pathways at the maternal-foetal interface
Thrombosis of the uteroplacental vasculature

Question 6

What are trophoblasts?

Answer 6

Precursor to placenta

Question 7

What other diseases is antiphospholipid syndrome associated with?

Answer 7

Other autoimmune disorders - SLE, RA, systemic sclerosis

Question 8

What are the defining clinical features of antiphospholipid syndrome

Answer 8

Thrombosis formation and/or recurrent pregnancy loss

Question 9

Describe thrombosis in antiphospholipid syndrome

Answer 9

Arterial
Venous
Microvascular

Question 10

What is the main feature in obstetrics of antiphospholipid syndrome

Answer 10

Recurrent pregnancy loss at any age

Question 11

What other obstetric conditions is antiphospholipid syndrome associated with?

Answer 11

Pre-eclampsia

Intrauterine growth restriction

Question 12

List some other manifestations of antiphospholipid syndrome

Answer 12

Livedo reticularis
Valvular heart disease - regurgitation
Renal impairment
Thrombocytopenia

Question 13

What is livedo reticularis

Answer 13

Red/blue/purple reticular pattern on the skin of the trunk, arms or legs

Question 14

Which valves are most affected in antiphospholipid syndrome

Answer 14

Aortic and mitral regurgitation

Question 15

Describe the renal impairment in antiphospholipid syndrome

Answer 15

Ischaemia in the small vessels of the kidney can result in chronic kidney disease

Question 16

Describe catastrophic antiphospholipid syndrome

Answer 16

Rare complication
1% of cases
Acute formation of microthromboses which causes infarction of multiple organs
20% triggered by major surgery, trauma or infection
Mortality rate of 50%

Question 17

What are the 3 main blood tests for antiphospholipid syndrome diagnosis?

Answer 17

Anticardiolipin
Lupus anticoagulant
Anti-B2-glycoprotein 1

Question 18

Describe anticardiolipin

Answer 18

Measures antibodies that bind cardiolipin (phospholipid)

Question 19

Describe lupus anticoagulant

Answer 19

Measures the clotting ability of the blood

Question 20

Describe the clotting ability of the blood in antiphospholipid syndrome

Answer 20

Prolonged clotting time in vitro

Question 21

Describe anti-B2-glycoprotein1

Answer 21

Detects antibodies that bind B2-glycoprotein 1 (a molecule that binds with cardiolipin)

Question 22

What percentage of healthy individuals test positive for antiphospholipid syndrome?

Answer 22

5%

Question 23

Describe the diagnostic criteria of antiphospholipid syndrome

Answer 23

1 clinical criteria plus 1 laboratory criteria

Clinical criteria:

• Vascular thrombosis - >1 episode of arterial, venous or small vessel thrombosis
• Pregnancy morbidity - >3 unexplained consecutive spontaneous abortions <10 weeks gestation or >1 premature birth of a normal neonate <34weeks because of eclampsia/severe pre-eclampsia or >1 unexplained death or morphologically normal foetuses at or beyond the 10th week gestation

Lab criteria

• Lupus anticoagulant - present in plasma on >2 occasions >12hr apart
• Anticardiolipin antibody - present in medium/high titre on >2 occasions >12 weeks apart
• Anti-beta2-glycoprotein 1 - present in serum or plasma on 2 or more occasions at least 12 weeks apart

Question 24

What does the management of antiphospholipid syndrome depend on?

Answer 24

The clinical presentation of the patient

Question 25

Describe the management of antiphospholipid syndrome in someone presenting with recurrent pregnancy loss >3

Answer 25

LMWH and Low dose aspirin (75mg OD)

Question 26

Describe the management of antiphospholipid syndrome in someone presenting with previous pre-eclampsia/IUGR

Answer 26

Low dose aspirin (75mg) throughout subsequent pregnancy

Question 27

Describe the management of antiphospholipid syndrome in someone presenting with vascular thrombosis

Answer 27

Long term anticoagulation with warfarin (target INR 2-3). Target INR can be increased if thrombosis was arterial
Switch warfarin to LMWH if pregnant/trying to conceive