Antiphospholipid syndrome

From Ganfyd

An autoimmune disorder of recurrent thrombosis and/or pregnancy loss. Can exist in isolation, else in association with systemic lupus erythematosus. In children, development of SLE appears to be inevitable. A mixed bag of conditions, despite the name, where there may be antiphospholipid antibodies (of one sort or another eg anti-plasma protein β₂-glycoprotein 1), or positive anticardiolipin, or positive lupus anticoagulant tests (persistently).

Thrombosis can be arterial (e.g. causing stroke or heart attack) OR venous (e.g. causing deep vein thrombosis). Other associated features are:

• Livedo reticularis
• Thrombocytopenia
• Nephropathy
• Neurological manifestations esp. migraine
• Haemolytic anaemia

Clearly some of these are autoimmune rather than thrombotic in nature. If antiphospholipid antibodies are found incidentally, thrombosis is unusual. But can be catastrophic viz microangiopathy, pulmonary haemorrhage, ARDS, cerebral/adrenal infarction, Budd-Chiari syndrome.

Treatment

Acute treatment is with IV or subcut heparin, followed by warfarin (target INR 2-3). Aspirin may be added if problematic. Hydroxychloroquine should probably always be used. Avoid smoking, oestrogens, cocaine etc. Plasma exchange and Rituximab may be used in life-threatening cases.

Since the risk of thrombosis is so low if antiphospholipid antibodies are found incidentally, unless there is a suggestion of lupus, prophylaxis is probably unnecessary. If in doubt or if some other risk factor, low dose aspirin seems reasonable. Potential complications of warfarin therapy must be considered.

The antibodies act by inducing adhesion molecules from endothelial cells, upregulating tissue factor, activating platelets and the complement cascade generally.

References

Current Opinion in Hematology. 13(5):366-75, 2006

External links

• Hughes Syndrome Foundation - overview of the condition
• Hughes Syndrome Foundation - making the diagnosis

References