Page kidney

Renal hematoma diagram

Page kidney refers to a phenomenon where an external compression of the kidney, often due to a hematoma (a solid swelling of clotted blood within the tissues) or other mass, leads to hypertension (high blood pressure). This condition is named after Dr. Irvine Page, who first described it in 1939. The compression on the kidney, usually from trauma or sometimes spontaneously due to a tumor or cyst, leads to decreased blood flow to the affected kidney. This triggers the renin-angiotensin-aldosterone system (RAAS), a hormone system that regulates blood pressure and fluid balance, causing the kidney to release renin. Renin then converts angiotensinogen to angiotensin I, which is further converted to angiotensin II, a potent vasoconstrictor that increases blood pressure. Additionally, angiotensin II stimulates the release of aldosterone, leading to sodium and water retention, further increasing blood pressure.

Symptoms and Diagnosis

Symptoms of a Page kidney may vary but often include hypertension, which may be sudden in onset, and flank pain. The diagnosis is typically made through imaging studies such as ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI). These imaging techniques can identify the external compression and its effects on the kidney structure and function.

Treatment

Treatment of a Page kidney aims to relieve the external pressure on the kidney and manage hypertension. In cases where a hematoma is causing the compression, surgical intervention may be necessary to drain the hematoma and relieve pressure. In other instances, management of hypertension with medication may be sufficient, especially if the compression is due to less acute causes. In some cases, removal of the offending mass or even the affected kidney (nephrectomy) may be considered if other treatments fail and the patient's health is severely compromised.

Epidemiology

The exact prevalence of Page kidney is difficult to determine due to its often asymptomatic nature and the varied underlying causes. However, it is considered a rare cause of secondary hypertension.

Prognosis

The prognosis for individuals with a Page kidney largely depends on the cause and severity of the compression, as well as the timeliness and effectiveness of treatment. If treated appropriately, individuals can often manage the hypertension and maintain normal kidney function.