Thrombosis in nephrotic syndrome.

Nephrotic syndrome (NS) is characterized by heavy proteinuria, edema, hypoalbuminemia, and hyperlipidemia and the most frequent causes are glomerular diseases. An uncommon presentation is iatrogenic NS, an adverse effect of some drugs administration. In the clinical course of NS, a typical feature is dysregulated coagulation state, promoted by the breakdown of permselectivity barrier of the glomerular capillary wall, resulting in the leakage of high-molecular-mass proteins, at least the size of albumin. This hypercoagulable condition is supported by several factors, such as abnormalities in platelet activation and an imbalance between anticoagulation/antithrombosis and procoagulant/prothrombotic mechanisms. Thus, NS and the risk of developing thromboses are strictly related. Thrombotic events affect the venous system rather than arterial vessels with different features and frequencies. Deep venous system of the lower extremities and renal veins are the most frequent source of pulmonary embolism, the most dangerous NS complication. Prophylactic anticoagulation and thrombosis treatment are not clearly established because large randomized trials and guidelines are lacking. The management of NS and the decision of when and how to anticoagulate the patient represent a teamwork challenge for physicians.