Renal vein thrombosis with inferior vena cava extension and pulmonary embolism in a patient with acute pyelonephritis: a case report and updated literature review.
Sutanto R, Koesbandono, Masui M, Octavius G • CEN case reports • 2026
Renal vein thrombosis is a rare, underrecognized complication of acute pyelonephritis; in this case and a pooled review of 24 cases, most patients did well with antimicrobials and anticoagulation alone, and RVT should be considered when suspected pyelonephritis worsens despite appropriate therapy or looks atypical.
Key Findings
Results
A previously healthy 29-year-old man with acute left pyelonephritis developed extensive left renal vein thrombosis extending into the suprarenal inferior vena cava.
He presented with a two-week history of left flank pain and fever.
Contrast-enhanced computed tomography showed acute left pyelonephritis with extensive renal vein thrombosis extending into the suprarenal inferior vena cava.
The diagnosis was made on imaging, and the clinical features overlapped with those of the underlying infection.
Results
Pulmonary embolism developed during hospitalization despite anticoagulation having been started.
Pulmonary embolism occurred after anticoagulation was initiated in the case patient.
The abstract notes that diagnosis of RVT is often delayed until thrombus propagation or embolization occurs.
Results
No causative organism was identified in the case, and thrombophilia screening was negative.
Cultures did not identify a causative organism.
A low-count Staphylococcus haemolyticus isolate was considered a contaminant.
Thrombophilia screening was negative.
Results
The case patient improved with antimicrobial therapy and anticoagulation alone, with no invasive intervention.
The abstract states he "improved with antimicrobial therapy and anticoagulation alone, requiring no invasive intervention."
Results
A literature review identified 23 prior published cases of acute pyelonephritis-associated RVT, which were pooled with the present case (n = 24).
The search was done in PubMed.
The pooled acute pyelonephritis cases were analyzed separately from five xanthogranulomatous pyelonephritis-associated cases.
Three cases were excluded for systemic or multifactorial thrombosis, and one case of RVT radiologically mimicking pyelonephritis was excluded.
Results
Gram-negative organisms predominated in pooled cases, and diabetes mellitus was present in fewer than half of patients.
Gram-negative organisms accounted for 78.3% of cases.
Diabetes mellitus was present in fewer than half of patients.
Results
Most pooled cases had favorable outcomes with antimicrobial therapy and anticoagulation alone, while invasive interventions were reported selectively.
Invasive interventions were reported in cases with extensive thrombus burden or uncontrolled infection.
Background
RVT is a rare, underrecognized complication of acute pyelonephritis, and nephrotic syndrome and malignancy remain the predominant causes of RVT overall.
Clinical features of RVT overlap with the underlying infection, so diagnosis is often delayed.
Delay often continues until thrombus propagation or embolization occurs.
Conclusions
RVT should be considered in suspected pyelonephritis that deteriorates despite appropriate therapy or has atypical clinical or imaging features, with individualized management.
When infection and RVT coexist, the temporal relationship and causality may remain uncertain.
Diagnosis and management should be individualized by clinical presentation, thrombus extent, severity of infection, and imaging findings.
What This Means
This report describes a healthy 29-year-old man with a kidney infection (pyelonephritis) who developed a large blood clot in the vein draining the left kidney. The clot extended into the body's main large vein (the inferior vena cava), and a clot also traveled to the lungs while he was in hospital, even after blood thinners were started. No clear germ was found, and tests for inherited clotting disorders were negative. He recovered with antibiotics and blood thinners alone, without surgery or other procedures.
The authors also pooled their patient with 23 previously published cases of kidney-infection-related vein clots. Most infections were caused by gram-negative bacteria (78.3%), and fewer than half of patients had diabetes. Most people did well with antibiotics and blood thinners, while procedures were used mainly when the clot was very large or the infection could not be controlled.
This research suggests that doctors may need to consider a kidney vein clot when a presumed kidney infection does not improve with proper treatment or looks unusual on scans or in symptoms. Because this is a case report plus a review of small published case reports, it cannot show how common the problem is or prove that the infection caused the clot. The authors emphasize that care should be tailored to each patient.
Sutanto R, Koesbandono, Masui M, Octavius G. (2026). Renal vein thrombosis with inferior vena cava extension and pulmonary embolism in a patient with acute pyelonephritis: a case report and updated literature review.. CEN case reports. https://doi.org/10.1007/s13730-026-01206-2