Catastrophic antiphospholipid syndrome

Catastrophic antiphospholipid syndrome (CAPS), also called Asherson's syndrome, is a rare autoimmune condition where widespread clotting inside blood vessels leads to multiple organs failing. It stems from antiphospholipid antibodies that attack proteins in the body linked to phospholipids. These antibodies activate endothelial cells, platelets, and immune cells, triggering a massive inflammatory immune response and extensive clotting. Ronald Asherson first described the syndrome in 1992. CAPS involves thrombotic microangiopathy, clots in many organs, and sometimes tissue death, marking it as a severe, catastrophic form of antiphospholipid syndrome. Clinically, CAPS affects at least three organs and can involve many systems. It often features small-vessel clots in areas like the gastrointestinal tract and signs of acute respiratory distress syndrome (ARDS), a type of systemic inflammatory response syndrome (SIRS). Peripheral clots may occur in veins and arteries. Clots inside the abdomen can cause pain. The body has β2-GPI, a blood glycoprotein that acts as a natural anticoagulant by inhibiting certain platelet functions. Since anti-β2-GPI antibodies can form after bacterial exposure, the body becomes prone to excessive clotting, which activates toll-like receptor 4 and leads to a cytokine storm or thrombotic storm. A thrombotic storm can also arise from changes in coagulation and fibrinolysis that raise death rates, or from infections in children where IgM and IgG anti-β2-GPI antibodies signal endothelial cells to promote clotting. It is thought that prothrombotic genetic risk factors may speed up clotting after a first event, rather than environmental factors alone causing it. Complications often involve the heart, blood vessels, nerves, kidneys, and lungs. Heart issues include mitral valve regurgitation (where the valve leaks blood backward), angina (chest pain), and myocardial infarction (heart attack). Kidney problems can lead to low urine output and high blood pressure. Lung issues may cause rapid breathing (hyperventilation) and low oxygen levels (hypoxemia). The skin may show purpura and necrosis. Brain involvement can cause encephalopathy and seizures. Heart attacks and strokes from arterial clots may occur. Death can result from multiple organ failure.