Case presentation
A 49-year-old male presented to the hospital emergency department with left flank pain and hematuria. The patient’s flank pain, which had started gradually from a week earlier, was intermittent and did not spread anywhere, but had intensified over the past two days. He also complained of hematuria along with flank pain occurring once or twice a day and manifested as voiding of blood clots in his urine. Symptoms of decreased urinary output, fever, chills, nausea, vomiting, diarrhea, and dysuria were not mentioned. He had a past history of extensive deep vein thrombosis (DVT) in the lower right limb about five years earlier. and as he did not have any provoking factors, thrombophilic tests was checked and showed negative results (antithrombin III, factor V Leiden , lupus anticoagulant, and anti-cardiolipin IgG and IgM). Therefore, he received 7.5 mg daily warfarin tablets for five years. Six months earlier, he decided to discontinue treatment and take Aspirin 80 mg tablet daily without medical consultation. The patient also reported a history of COVID-19 about three months earlier. He did not report a history of prolonged travel, surgery, cancer, trauma, or bedridden state. His sister had a history of DVT and died of pulmonary thromboembolism due to Lack of cooperation in treatment process. On examination, the patient was conscious and oriented and his vital signs were blood pressure 120/80 mmHg, heart rate 126 beats/min, respiratory rate 19 breaths /min, saturations 96% on room air and body temperature 36.5°C. On physical examination, the heart and lungs were normal and fatty abdominal distension. No bruit was heard in the renal artery pathway. Left lower quadrant (LLQ) and costovertebral angle (CVA) tenderness was detected during abdominal examination. On limb examination, there was no swelling and both sides had similar sizes and strong symmetrical pulses. He was referred to the hospital with a color doppler ultrasound examination of kidneys which showed normal arterial flow velocity and pattern in intrarenal and main interlobar arteries in the right kidney. The size and parenchymal thickness of the right kidney were 129 mm and 16 mm, respectively. No pathological complication was observed in the right intrarenal and main renal veins. The left kidney was edematous and swollen leading to the loss of corticomedullary differentiation. The size and parenchymal thickness of the left kidney were 168 mm and 25 mm, respectively. A filling defect was evident in the left renal hilum, suggesting a thrombus measuring 51 × 23 mm in the main renal vein (Figure 1). Examination of the renal vein at the periphery of the inferior vena cava (IVC) and its distal portion also showed extensive thrombosis reaching the site where the vein drains into the IVC (70 mm in diameter) without evidence of thrombotic spread to the IVC. IVC had a normal flow. The resistance index of the interlobar arteries of the left kidney was at the upper normal limit and left renal arterial flow was normal. Clear recanalization in the left renal vein was not appraisable.