Introduction: It is common experience to all urologists to manage many patients admitted at night from the casualty ward with a diagnosis of "therapy-resistant renal colic". However not all the patients with flank pain really suffer for renal colic, although painful somatic irradiation refers to the same areas.
Case report: A seventy years old male patient was admitted from the casualty ward for left renal colic. Laboratory tests showed normal creatinine, mild reduction of albuminemia, elevated triglycerides and cholesterol at the upper limit of normal. The pain had risen sharply a few hours before. For some years the patient suffered nocturia, but he never made an urologic consultation. Ultrasonography performed in the casualty ward demonstrated normal findings with no hydronephrosis but the presence of left perirenal extravasation with "casting-like" aspect and extending to the pelvis. Contrast-enhanced computed tomography (CT) revealed the presence of left renal vein thrombosis and acute segmental pulmonary embolism. The left kidney, apart from increased volume and reduced parenchymal impregnation, showed no neoplastic nodule. The case presented as unusual according to the opinion of consulted nephrologists, vascular surgeons and urologists (also from others hospitals and universities). After informed consent of the patient (stressing seriousness and singularity of his condition), we decided to treat him as a deep vein thrombosis. We administered an heparin bolus (80UI/kg), followed by the infusion of heparin (18UI/kg/h) using a peristaltic pump for 14 days.
Results: CT performed after 14 days of treatment showed the full resolution of renal vein thrombus and of pulmonary embolism. Thereafter a nephrotic syndrome was diagnosed and the patient was took in care by the nephrologist. Nephrotic syndrome preceded the hospital admission of the patient and was the etiological cause of renal vein thrombosis.
Discussion: The well known causes of acute flank pain reported in textbooks include renal and perirenal inflammatory processes, renal cell or transitional cell cancers of the kidney or of the urinary tract, obstruction of the urinary tract by stones or stenosis, hydronephrosis of different etiology whereas vascular causes are not often mentioned.
Conclusions: After the diagnosis of left renal vein thrombosis, the more probable associated urological is a renal cell carcinoma. Excluding renal cancer other possible causes of thrombosis are medical conditions such as amyloidosis, multiple myeloma, nephrotic syndrome, thrombophlebitis.