page kidney

Page kidney, or Page phenomenon, refers to systemic hypertension secondary to extrinsic compression of the kidney by a subcapsular collection, e.g. hematoma, seroma, or urinoma.

Clinical presentation

Patients present with hypertension, which may be recognized acutely after an inciting event or following a delay . In the acute setting, patients may complain of flank pain. Reduced renal function may be noted.

Pathology

Compression of the kidney results in compression of the intrarenal vessels, which leads to decreased blood flow to the renal parenchymal tissue and induction of renin secretion. Renin-angiotensin system activation results in hypertension.

Etiology

Patients usually have an inciting event that leads to the development of a subcapsular collection, such as trauma or surgery. In some cases, spontaneous rupture of a mass, aneurysm, or cyst can be responsible .

Radiographic features

All modalities will demonstrate a collection surrounding the kidney, of variable density/intensity/echogenicity depending on the nature of the collection. The collection is usually subcapsular in location, maintaining a reniform contour. Importantly, however, the adjacent renal parenchyma should be distorted.

Ultrasound

On Doppler evaluation, renal arterial resistive index is elevated .

CT

On contrast-enhanced examination, the affected kidney may demonstrate a delayed nephrogram.

History and etymology

This phenomenon was first described by Irvine H (Heinley) Page (1901-1991) in 1939 when he discovered that hypertension could be produced in a dog by wrapping one or both kidneys in cellophane. Dr Page was a renowned American cardiologist and is remembered for his research into hypertension, in particular his discovery of serotonin and his work on the renin-angiotensin system.

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