History and exam

Key diagnostic factors

common

history or current diagnosis of vascular thrombosis

History of one or more episodes of venous, arterial, or microvascular thrombosis confirmed by objective imaging or histopathology. This includes the less common presentations of stroke, coronary artery thrombus, peripheral arterial disease, and renal thrombotic microangiopathy.[4]​​

history of pregnancy loss

Three or more consecutive pregnancy losses at <10 weeks' gestation and/or unexplained fetal death >10 weeks' gestation.[4]​​

uncommon

history of pregnancy-associated morbidity

Premature delivery (<34 weeks' gestation) due to preeclampsia, placental abruption, or intrauterine growth restriction (i.e., signs of placental insufficiency).

Other diagnostic factors

common

history of systemic lupus erythematosus

Up to 36% of patients with APS have a history of systemic lupus erythematosus, and another 5% have a lupus-like syndrome.​[4]

features of thrombocytopenia

May be present in APS, often due to an immune mechanism or the presence of another autoimmune disease (idiopathic thrombocytopenic purpura). The incidence of hemorrhage associated with this is rare. Features of thrombocytopenia include petechial rash or symptoms of mucosal bleeding.

arthralgia/arthritis

Complaints of arthralgia (39%) and arthritis (27%) are common and are either due to underlying systemic lupus erythematosus or lupus-like disease (if the patient does not have enough criteria to fulfill the definition of systemic lupus erythematosus).[4]​​

livedo reticularis

This mottled purplish discoloration of the skin, which can be blanching or nonblanching on pressure, is present in up to 20% of patients with APS. The nonblanching livedo reticularis is due to fibrin deposition at the periphery of the circulation of skin arterioles.​​[Figure caption and citation for the preceding image starts]: Livedo reticularisFrom the personal teaching collection of Professor Hunt; used with permission [Citation ends].com.bmj.content.model.Caption@5adf6770​​[Figure caption and citation for the preceding image starts]: Livedo reticularisFrom the personal teaching collection of Professor Hunt; used with permission [Citation ends].com.bmj.content.model.Caption@62c436d7

uncommon

history of other rheumatologic disorders or connective tissue disorders

Evaluation of a large cohort of patients with APS showed that nonlupus-like rheumatologic disorders occurred in the following frequencies: primary Sjogren syndrome (2.2%), rheumatoid arthritis (1.8%), systemic sclerosis (0.7%), systemic vasculitis (0.7%), and dermatomyositis (0.5%).[4]​​

cardiac murmur

Vegetations, valve thickening, and heart valve dysfunction seem to be more frequent in APS than in patients with systemic lupus erythematosus alone. This is known as Libman-Sacks endocarditis and may relate to fibrin deposition on the valves. The mitral valve is most commonly affected. Up to 20% of patients with APS have valve abnormalities, although they rarely cause hemodynamic problems.[40]​​

edema

Patients occasionally present with signs or symptoms of nephropathy (edema and proteinuria) due to microangiopathic thrombosis secondary to antiphospholipid syndrome.[31]

seizure, headache, memory loss, signs of transverse myelopathy

Patients presenting with stroke or transient ischemic attack, especially if <50 years of age, should raise suspicion for an underlying diagnosis of APS. Less common neurologic presentations include seizure, headache, memory loss, transverse myelopathy, and rarely chorea gravidarum in pregnancy.[32][33]

limb discomfort, swelling, skin discoloration, and ulcers

Up to 30% of patients can experience postphlebitic syndrome following an episode of deep vein thrombosis. This can manifest as limb discomfort, swelling, skin discoloration, and ulcers.[34]

Risk factors

strong

history of systemic lupus erythematosus

Although systemic lupus erythematosus (SLE) is not considered a criterion for diagnosis, up to 36% of patients have a history of SLE, and 5% have a lupus-like syndrome (symmetric joint pain and fatigue).[4]​​

history of other autoimmune rheumatologic disorders

Evaluation of a large cohort of patients with antiphospholipid syndrome showed that nonlupus-like rheumatologic disorders occurred in the following frequencies: primary Sjogren syndrome (2.2%), rheumatoid arthritis (1.8%), systemic sclerosis (0.7%), systemic vasculitis (0.7%), and dermatomyositis (0.5%).[4]​​

history of other autoimmune diseases

There is a strong association with other autoimmune disease such as hypo- and hyperthyroidism, pernicious anemia, celiac disease, and Addison disease, and routine follow-up should involve assessment for their development.[1]

weak

history of autoimmune hematologic disorders

Antiphospholipid antibodies are detected in around 25% of patients with immune thrombocytopenic purpura, and less commonly in autoimmune hemolytic anemia; 10% of patients with antiphospholipid syndrome antibodies have a positive Coombs test but it is rarely associated with active hemolysis.[6][27][28]

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