Antiphospholipid Syndrome

The Antiphospholipid Syndrome (APS) was first described in the early 1950s in women who were noted to have prolonged bleeding times that were not correctable by addition of normal plasma, history of hypercoagulability, false-positive VDRL, and a history of recurrent pregnancy loss.

The lupus anticoagluant and the anticardiolipin antibody were characterized as acquired antibodies. Clinical and serologic criteria for the classification of APS have been proposed on the basis of a study of 667 SLE patients:

Classification of Antiphospholipid Syndrome

Clinical manifestations:

  • Vascular thrombosis (one or more clinical episodes of arterial, venous, or small vessel thrombosis).
  • Pregnancy morbidity (one or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation / one or more premature births at or before the 34th week of gestation / three or more unexplained consecutive spontaneous abortion before the 10th week of gestation).

Laboratory criteria:

  • Anticardiolipin antibodies (IgG and/or IgM)
  • Lupus anticoagulant

Definite antiphospholipid antibody syndrome is considered to be present if at least 1 of the clinical criteria and 1 of the laboratory criteria are met.

Multiple faces of the antiphospholipid syndrome

(Asherson RA, Cervera R (2003) Autoim Rev 2: 140-151)

Single vessel involvement or multiple vascular occlusions may give rise to a wide variety of presentations.

Deep vein thrombosis, sometimes accompanied by pulmonary embolism, is the most frequently reported manifestation in this syndrome (about 39 %).
Cerebrovascular accidents - either stroke (20 %) or transient ischemic attacks (11 %) - are the most common arterial thrombotic manifestations.
Early fetal loss (35 %), late fetal loss (17 %), premature birth (11 %), and pre-eclampsia (10 %) ar the most frequent fetal and obstetric manifestations.

Several other clinical features are relatively common in these patients, i.e. thrombocytopenia (30 %), livedo reticularis (24 %), heart valve lesions (12 %), hemolytic anemia (10 %), epilepsy (7 %), myocardial infarction (6 %), leg ulcers (6 %), and amaurosis fugax (5 %).

However, a large variety of clinical manifestations have been occasionally described in patients with APS, with prevalences lower than 5 %. Virtually any organ, system or tissue of the body can be affected. 
APS can be manifested in such diverse conditions such as chorea, intracardiac thrombus, ARDS, Addison's disease, Budd-Chiari syndrome, AVN of bone or HELLP syndrome, just to name a few. 


As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.