Presentation
Episodes of hypertension; history of extracorporeal shock wave lithotripsy few months prior
Patient Data
Large hypoechoic organizing subcapsular perirenal fluid collection measuring approximately 411 cc compressing and distorting the left renal parenchyma. There is also a 0.4 cm calculus in the inferior calyx.
Case Discussion
Page kidney occurs when there is sustained renal parenchymal compression, causing hypoperfusion and thus activating the renin–angiotensin–aldosterone system (RAAS). The subcapsular space is a potential space where fluids such as blood, urine, exudates, and lymph may accumulate. The most common cause is traumatic or iatrogenic subcapsular hematomas. Common iatrogenic causes include renal biopsies, shockwave lithotripsy, or ureteronephroscopic procedures.
There is significant variability in the time between the inciting event and the diagnosis of hypertension. In some cases, the traumatic event may not even be identified.