Historical perspective

Renal vein thrombosis (RVT) poses a diagnostic and management challenge to pediatric hematologists, nephrologists, radiologists and neonatologists [1,2]. Such challenges are exemplified by one of the first descriptions of RVT in the literature in 1837 in which Pierre Rayer described the association between RVT and infancy. Three years later he described the association between nephrotic syndrome and RVT [3].

These first descriptions are fitting as the vast majority of cases occur in the neonatal period while the rare cases that do occur outside this period are typically associated with either primary or secondary renal disease or local vascular compression. Many of the first descriptions of RVT were reported in the European literature from the 1840s to the 1920s [3,4]. Subsequently, from the 1920s to the 1960s, the descriptions of RVT were noted mostly in the setting of its discovery at the time of surgery in a decompensating neonate followed by nephrectomy or at autopsy [5–7]. Although described nearly 190 years ago, the exact etiology of RVT remains still largely unknown but is likely related to the underlying disease, host characteristics and local and systemic risk factors. These factors include a reduced renal perfusion in the perinatal period, local inflammation and/or vascular obstruction, and coagulation-related issues either related to developmental hemostasis (i.e., the physiologic reduction of natural anticoagulants early in life) or to an inherited/acquired thrombophilia trait. In fact, thrombophilia was not recognized as a potential association until the 1990s, when most of the currently recognized inherited traits were characterized and initially thought to be the etiology of many pediatric thrombotic events.