Antiphospholipid syndrome can cause (arterial/venous) blood clots (in any organ system) or pregnancy-related complications (especially miscarriages in the second or third trimester). In APS patients, the most common venous event is deep vein thrombosis of the lower extremities (blood clot of the deep veins of the legs). The most common arterial event is a stroke. Patients presenting with antiphosphoplipid syndrome have a positive history of deep venous thrombosis, myocardial infarction and stroke. Last trimester miscarriages, history of heart murmurs or cardiac valvular vegetations and hemolytic anemias may also be present.

Patients presenting with antiphosphoplipid syndrome (APS) may have a positive history of:^[1][2][3]

• Thrombosis such as DVT/PE, MI, transient ischemic attack (TIA), stroke, especially if recurrent, at an earlier age, or in the absence of other known risk factors.
• Miscarriage (especially late trimester or recurrent) or premature birth
• History of nephropathy
• History of hematologic abnormalities, such as thrombocytopenia or hemolytic anemia
• History of heart murmur or cardiac valvular vegetations

• Nonthrombotic neurologic symptoms, such as migraine headaches, chorea, seizures, transverse myelitis, Guillain-Barré syndrome, or dementia.
• Pulmonary hypertension
• Unexplained adrenal insufficiency
• Avascular necrosis of bone in the absence of other risk factors

Common symptoms of APS can be divided into major and minor features:

Major features:

• Fatigue
• Fever
• Weight loss

• Venous thrombosis (most common site is the lower extremities) such as deep venous thrombosis
• Arterial thrombosis (most common in the cerebral vasculature) such as stroke or transient ischemic attack
• Thrombocytopenia
• Recurrent fetal loss

Minor features:

• Migraine
• Chorea

Less common symptoms of APS include:

• Lymphadenopathy

• Myocardial Infarction
• Stroke
• Pulmonary embolism
• Amaurosis fugax
• Retinal infarct
• Peripheral or deep venous occlusion
• Raynaud’s syndrome
• Pulmonary hypertension
• Avascular necrosis
• Recurrent fetal loss (especially in the 2nd or 3rd trimester)
• Pre-eclampsia
• Adrenal insufficiency