Ask Upmark Kidney

Ask Upmark kidney is a rare form of segmental renal hypoplasia which was first described by Ask Upmark in 1929 [1]. This condition commonly occurs in young females and almost always associated with hypertension. The lesion can be focal or diffuse and it can involve one or both kidneys [2]. The Ask Upmark kidney is a morphologically abnormal kidney due to scarring, which is secondary to vesicoureteric reflux with associated intarenal reflux. Clinically they present with severe hypertension and patients are usually of pediatric or adolescent age group. They show abnormal rennin secretion which is thought to be the cause for hypertension [3]. The characteristic pathological feature is deep transverse or circumferential grooves which give rise to a lobular surface of the kidney [2]. Histologically the hypoplastic segment show cystic and dilated tubules lined with a single layer of flat epithelium that are filled with colloid like substance, giving the characteristic “thyroid like” appearance [1]. These hypoplastic segments are typically devoid of glomeruli which helps it differentiate it from chronic pyelonephritis. Although the Ask Upmark kidney initially described as a congenital abnormality, recent experimental studies indicate that vesicoureteral reflux in utero or in infancy may play an important role in the development of renal segmental hypoplasia. Imaging helps to demonstrate the morphological changes of the kidney. Plain abdominal radiograph would show a lobular configuration of the involved kidney. Intravenous pyelogram demonstrates a combination of cortical thinning and altered appearance of calyces. The calyces in the atrophied area is dilated and clubbed with elongation of the corresponding infundibulum [2]. On Grey scale ultrasound scan the renal size can be normal or decreased and it clearly depicts the groove involving the renal cortex with cortical thinning. Angiographic studies will demonstrate the renal artery and the ostium to be smooth but smaller in size [2]. The patients who has unilateral focal disease and presents with hypertension, nephrectomy had shown to be curable [2].