Systemic capillary leak syndrome: a nosological entity that the nephrologist must be aware of

Capillary leak syndrome occurs when plasma leaks out of capillaries into muscles, tissues, organs and body cavities. There are two major types of capillary leak syndrome: 1. secondary capillary leak syndrome: it is a single episode triggered by another disease, condition or drug; 2. idiopathic systemic capillary leak syndrome: it is a rare disease characterized by recurrent episodes of acute life-threatening episodes of shock, hemoconcentration, and hypoalbuminemia. An increase in capillary permeability results in reversible plasma movement into the interstitial spaces followed by the appearance of related symptoms or complications, including acute kidney injury. Cytokines are likely to be important in the pathophysiology of systemic capillary leak syndrome. Fluid management is a critical part of the treatment of systemic capillary leak syndrome: hypovolemia and hypotension can cause organ injury, whereas capillary leakage of administered fluid can worsen organ edema leading to progressive organ injury.Although systemic capillary leak syndrome is a rare entity, it can be life-threatening. The nephrologist must be aware of the potential and serious complications linked to this pathology, including the need for kidney replacement therapy. This review aims to increase awareness of systemic capillary leak syndrome in the nephrology community.