Capillary leak syndrome (SCLS (for systemic capillary leak syndrome))

Capillary leakage is not a single molecule or receptor but rather a pathophysiological process characterized by the escape of plasma from small blood vessels into surrounding tissues. This leads to symptoms such as rapid drop in blood pressure, swelling, thickened blood, hypoalbuminemia, and potentially life-threatening complications like organ failure and pulmonary edema. The most well-known clinical entity is systemic capillary leak syndrome (SCLS), also called Clarkson disease. SCLS can be idiopathic or secondary to triggers such as sepsis, autoimmune diseases, viral infections including COVID‑19, certain medications like interleukins or chemotherapy agents. The underlying mechanism involves transient increases in vascular permeability due to dysfunction of the endothelial barrier—possibly mediated by inflammatory cytokines and factors like VEGF and angiopoietin‑2—but no specific molecular target has been identified. Treatment focuses on supportive care during acute episodes; some patients benefit from prophylactic use of beta agonists or phosphodiesterase inhibitors. Capillary leakage itself is not considered a therapeutic target but rather an endpoint resulting from upstream molecular events; thus it does not fit standard definitions for drug targets such as receptors or enzymes[1][3][4][5].

Other names

Systemic capillary leak syndromeVascular leak syndromeClarkson disease

For preventive/treatment drugs: - Beta agonists increase endothelial barrier function. - Phosphodiesterase inhibitors stabilize endothelium. - Leukotriene receptor antagonists reduce inflammation-mediated permeability[5]. For causative drugs/agents: - Chemotherapy agents and monoclonal antibodies may disrupt endothelial integrity.