Acute Pyelonephritis with Renal Vein and Inferior Vena Cava Thrombosis: A Case Report

Acute pyelonephritis might be complicated by the formation of renal and perirenal abscesses and very rarely by renal vein thrombosis (RVT), which is a life-threatening condition. We report a case of 35-year-old female with no significant past medical history, who presented a week history of fever, hematuria, flank pain, and lower urinary tract symptoms. Physical examination showed a shivering young woman with fever 39°C of temperature, left flank pain and tenderness was observed on palpation. Laboratory test results showed elevated CRP level at 210 mg/L, white blood cell count at 23000/mm3 with 14000/mm3 neutrophil. Urinalysis showed pyuria, bacteriuria and nitrites presence. Urine cultures grew Escherichia coli and blood cultures were sterile. Unfortunately, after 2 days of antibiotic therapy the patient flank pain worsened, and further imaging evaluation with Abdominal CT scan showed extensive thrombosis of the left renal vein and its branches protruding to the inferior vena cava. The patient improved after intravenous antibiotics and anticoagulation treatment. At 1-month follow-up, the patient was asymptomatic. At 3 months follow-up, CECT showed complete resolution of the IVCT and attenuated renal vein with atrophic small kidney. In conclusion, renal venous thrombosis secondary to acute pyelonephritis is very rare. It is very important to treat it rapidly because it can lead to pulmonary embolism, thrombosis of the inferior vena cava or renal failure, thus jeopardizing the patient's vital and functional prognosis.