The present study is a prospective evaluation of 151 patients with the
nephrotic syndrome in regard to the incidence of renal vein
thrombosis, modes of clinical presentation, pathogenetic course and response to
anticoagulant therapy. Of the 151 nephrotic patients studied, 33 had renal vein
thrombosis and
membranous nephropathy was present in 20. There were two modes of clinical presentation: (1) a sudden renal vein
thrombosis was observed in the young patient with acute
flank pain, marked costovertebral angle tenderness and macroscopic
hematuria; a characteristic intravenous pyelogram, renal histologic changes and
anticoagulant therapy were followed by marked improvement in renal function; (2) long-term renal vein
thrombosis was observed in the older patients; they were asymptomatic and intravenous pyelograms disclosed no abnormalities; there were no suggestive renal histologic findings; the incidence of thromboembolic phenomena other than renal vein
thrombosis was high, and there was mild progressive deterioration of renal function which was not altered by
anticoagulant drugs; treated nephrotic patients with chronic renal vein
thrombosis did not experience a new episode of
thromboembolism whereas untreated nephrotic patients without renal vein
thrombosis did. Finally, the sequence of
nephrotic syndrome leading to renal vein
thrombosis was clearly established showing the pathogenetic role of the
nephrotic syndrome in renal vein
thrombosis. Possible mechanisms in the pathogenesis of renal vein
thrombosis are also discussed.