Pickering Syndrome Physiology from Focal Intrarenal Segmental Renal Artery Stenosis: An Under Recognized Cause of Recurrent Hypertensive Emergencies.

Pickering syndrome is an uncommon but clinically significant manifestation of renovascular disease, classically characterized by recurrent hypertensive emergencies and flash pulmonary edema in the setting of bilateral renal artery stenosis or unilateral stenosis in a solitary functioning kidney. Focal intrarenal or segmental renal artery stenosis is an underrecognized anatomic pattern that may produce similar physiologic effects and may be overlooked when diagnostic evaluation is limited to the main renal arteries. We report the case of a 34-year-old woman with recurrent hypertensive emergencies complicated by flash pulmonary edema, preserved left ventricular systolic function, and progressive renal dysfunction. Renal duplex Doppler ultrasonography demonstrated abnormal intrarenal hemodynamics confined to an upper-pole segmental artery of the left kidney, including absent end-diastolic flow and a markedly elevated resistive index (RI = 1.0), while flow velocities in the main renal arteries were normal. These intrarenal Doppler findings, in the setting of reduced renal functional reserve and recurrent cardiopulmonary decompensation, were suggestive of Pickering physiology. This case highlights probable focal intrarenal renovascular disease as a potential and underrecognized cause of Pickering physiology and underscores the diagnostic value of comprehensive intrarenal Doppler waveform analysis, as reliance on main renal artery assessment alone may fail to identify functionally significant segmental disease. Recognition of regional disparities in intrarenal flow patterns can provide critical diagnostic insight, particularly when cross-sectional angiographic imaging is not feasible. In patients with reduced renal functional reserve, even focal segmental renovascular disease may produce severe systemic hemodynamic consequences, emphasizing the need for heightened diagnostic vigilance.