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Antiphospholipid Syndrome (APS) is an emerging condition that may underlie more conditions than first perceived. The diverse symptoms of APS include deep venous thrombosis of lower limbs, pulmonary embolism, early and late miscarriages, memory impairment, clinical features of arthritis, livedo reticularis, migraine or epilepsy.1,2
APS is a systemic autoimmune disease in which antibodies are directed against phospholipid-protein complexes.2,3
APS is more common in women than men in about a 5:1 ratio. Although the mean onset age of clinical manifestations tends to occur in the middle-age range, it may manifest in children and older patients as well. APS appears to lead directly to a combination of symptoms. Headaches – particularly migraines – going back to childhood and often with family history can be an early feature of APS.2
Recognizing the following clinical manifestations is an important step towards an earlier diagnosis:4
Other common and important signs are:4
Venous and arterial thromboses: the hallmarks of APS1,4
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.
Fetal and obstetric manifestations5
Fetal and obstetric manifestations of APS are also common with prematurity (28%), early pregnancy loss (18%), preeclampsia (up to 8%).
Currently there are no clinical guidelines for the diagnosis of APS; the only available guidance is the classification criteria which are primarily intended for clinical research. The classification criteria for APS require the identification of at least one clinical and one laboratory criterion.3
One or more clinical episodes of arterial, venous, or small-vessel thrombosis in any tissue or organ. Thrombosis must be confirmed by objective validated criteria. For histopathological confirmation, thrombosis should be present without significant evidence of inflammation in the vessel wall.
One or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation, OR one or more premature births of a morphologically normal neonate before the 34th week of gestation because of:
While thrombosis and fetal and obstetric complications are the most recognizable clinical signs of APS; and included in the classification criteria; there is growing evidence of APS presenting with other symptoms.
Some symptoms that should prompt you to consider diagnostic testing for APS include: heart valve lesions; headaches, epilepsy; livedo reticularis; and other autoimmune conditions.3
The hallmark serological testing result that defines APS is the presence of persistent antiphospholipid antibodies (aPL). To be classified as APS, international consensus of the classification criteria state that a patient must have elevated titers of one of the following antiphospholipid antibody (aPL):3,6
Lupus anticoagulant in plasma
Anticardiolipin antibodies (IgG and/or IgM), considered elevated medium or high titer (>40 GPL or MPL or > 99th percentile) in serum or plasma
Anti-β2-glycoprotein I antibodies (IgG and/or IgM), considered elevated titers a titer > 99th percentile in serum or plasma
These antiphospholipid antibodies are considered to be diagnostic markers and pathogenic drivers of APS.7 The classification criteria for APS states a patient who fulfills clinical criteria can be classified as APS dependent when the patient exhibits a persistently positive aPL result on two or more occasions at least 12 weeks apart.3,8