Antiphospholipid syndrome

Antiphospholipid syndrome is a disorder characterized by an increased tendency to form abnormal blood clots (thromboses) that can block blood vessels. This clotting tendency is known as thrombophilia. In antiphospholipid syndrome, the thromboses can develop in nearly any blood vessel in the body. If a blood clot forms in the vessels in the brain, blood flow is impaired and can lead to stroke. Antiphospholipid syndrome is an autoimmune disorder. Autoimmune disorders occur when the immune system attacks the body's own tissues and organs.

Women with antiphospholipid syndrome are at increased risk of complications during pregnancy. These complications include pregnancy-induced high blood pressure (preeclampsia), an underdeveloped placenta (placental insufficiency), early delivery, or pregnancy loss (miscarriage). In addition, women with antiphospholipid syndrome are at greater risk of having a thrombosis during pregnancy than at other times during their lives. At birth, infants of mothers with antiphospholipid syndrome may be small and underweight.

A thrombosis or pregnancy complication is typically the first sign of antiphospholipid syndrome. This condition usually appears in early to mid-adulthood but can begin at any age.

Other signs and symptoms of antiphospholipid syndrome that affect blood cells and vessels include a reduced amount of cells involved in blood clotting called platelets (thrombocytopenia), a shortage of red blood cells (anemia) due to their premature breakdown (hemolysis), and a purplish skin discoloration (livedo reticularis) caused by abnormalities in the tiny blood vessels of the skin. In addition, affected individuals may have open sores (ulcers) on the skin, migraine headaches, or heart disease. Many people with antiphospholipid syndrome also have other autoimmune disorders such as systemic lupus erythematosus.

Rarely, people with antiphospholipid syndrome develop thromboses in multiple blood vessels throughout their body. These thromboses block blood flow in affected organs, which impairs their function and ultimately causes organ failure. These individuals are said to have catastrophic antiphospholipid syndrome (CAPS). CAPS typically affects the kidneys, lungs, brain, heart, and liver, and is fatal in over half of affected individuals. Less than 1 percent of individuals with antiphospholipid syndrome develop CAPS.