Antiphospholipid syndrome

Question 1

Define

Answer 1

Characterised by the presence of antiphospholipid antibodies (APL) in the plasma, venous and arterial thromboses, recurrent foetal loss and thrombocytopenia.

Question 2

Causes

Answer 2

Unclear what acc causes development of these antibodies in the first place

Usually occurs as a primary disease but 20-30% are associated with SLE.

APL are directed against plasma proteins bound to anionic phospholipids e.g. beta 2-GP-I, prothrombin, annexin A5 and phospholipids.

APL may develop in susceptible individuals e.g. SLE patients, following exposure to infectious agents.

Once APL is present, a ‘second hit’ is required for the development of the syndrome.

Question 3

Epidemiology

Answer 3

More common in young females – accounts for 27% of females with >2 miscarriages

Question 4

Symptoms

Answer 4

Recurrent miscarriages

History of arterial thromboses – stroke

History of venous thromboses – DVT, PE

Hx of SLE/ other AI rheumatological disorders

Headaches, migraines

Chorea

Epilepsy

Question 5

Signs

Answer 5

Livedo reticularis – mottled purplish discolouration (blanching or non-blanching)

Livedo Reticularis or “mottling” is caused by reduced blood flow to the skin, it can be a normal phenomenon – particularly in babies and children. It can be a concerning sign e.g. if due severe sepsis or disseminated intravascular coagulopathy both of which have a high morbidity and mortality. It can be caused in various vasculitis AI conditions (dermatomyositis, rh arthritis), may be drug related, etc.

Signs of SLE – malar flush, discoid lesions, photosensitivity, athralgia

Signs of valvular heart disease - cardiac murmur

Features of thrombocytopenia e.g. petechia, mucosal bleeding etc.

Question 6

Investigation

Answer 6

FBC

• Low platelets
• ESR normal
• U&Es – APL nephropathy
• Clotting screen: high APTT

Presence of APT demonstrated by ELISA testing or lupus anticoagulant assays

Antibodies present: lupus anticoagulant, anti-cardiolupin, antiphospholipid, anti b2-microglobulin, ANA (elevated in SLE).

TO CONSIDER…

Venous doppler ultrasound/venography – to see if there are any clots

CT angio of chest – to see if PE is present