Post-biopsy renal allograft compartment syndrome: Addressing the problem, illustrated with a case report

Reversed diastolic intrarenal flow in page kidney following renal biopsy

Page's kidney is a condition that occurs due to external renal compression, usually caused by a subcapsular haematoma, generating a renal compartmental syndrome with parenchymal damage and renal perfusion alteration. Classically associated with renal trauma, Page's kidney can also arise after invasive renal procedures, such as renal biopsies or percutaneous nephrostomies. Clinically, it can trigger hypertension due to activation of the renin-angiotensin system induced by hypoperfusion secondary to renal parenchymal compression and can also present with varying degrees of renal function impairment. Furthermore, severe acute renal failure may be found particularly in patients with solitary kidneys or renal transplants. We present two cases of Page's kidney after renal biopsy and their PoCUS ultrasound findings. We would like to highlight the reversed diastolic flow on Doppler ultrasound in this entity, a pattern we have found in all two cases.

Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.^©RSNA, 2019.

Page kidney of renal allograft following blunt trauma

We report a case of the Page kidney phenomenon which occurred in a patient with a renal allograft following blunt trauma. The injury occurred following an accidental trip resulting in a trivial fall. The patient presented with acute graft dysfunction with no localizing symptoms or signs. His renal function deteriorated further and he also became hypertensive. Serial ultrasounds showed an increase in the size of perinephric hematoma and evidence of renal compression. Prompt surgical evacuation of the hematoma was performed and renal function returned to baseline. Serial ultrasound examinations and timely surgical intervention can prevent graft loss in this unusual situation.

Reversible acute anuric kidney injury after surgical evacuation of perinephric hematomas as a complication of renal transplant biopsies

Percutaneous renal transplant biopsy is the gold standard investigation to diagnose the cause of renal allograft dysfunction. There are inherent risks to this investigation, despite the procedure becoming safer due to the increased utilization of ultrasound-guided techniques. These biopsy risks can be increased when there is acute rejection present with a swollen transplanted kidney. Subcapsular hematomas are not uncommon after percutaneous renal transplant biopsies, but we describe two cases of post-biopsy subcapsular hematoma which were associated with acute renal allograft dysfunction in pediatric renal transplant recipients who did not have acute rejection.