Renal vein thrombosis associated with oral contraception and smoking: a case report from Japan, with literature review

Renal vein thrombosis, one of the common thrombotic complications of nephrotic syndrome or renal cell carcinoma, is reportedly a rare complication of hormonal contraception. Solitary renal vein thrombosis in the Japanese population is thought to be very rare because the incidence of venous thromboembolism is comparatively very low in Asian populations. We report a 38-year-old Japanese female with left renal vein thrombosis associated with oral contraception and concurrent smoking as the first Japanese case of solitary renal vein thrombosis associated with oral contraceptives, with a review of the literature. Seven cases were previously reported. The results revealed that all patients complained of acute onset of pain around the involved kidney without urinary symptoms or fever, and were effectively treated with anticoagulants. Other remarkable facts include that nausea and vomiting were frequently seen, and that the renal outcome was benign, despite various initial urine abnormalities. This report may alert clinicians to the importance of these risk factors as an etiology of renal vein thrombosis even in Asian populations. Clinicians should regard renal vein thrombosis as one of the differential diagnoses for acute flank pain in patients using oral contraceptives. A detailed history taking that reveals oral contraception, smoking, and other thrombophilic predispositions as well as timely computed tomographic scans would be the keys to diagnosis. Smoking cessation should be strongly recommended to oral contraceptive users, especially women over 35 years of age, regardless of dosage.