1 Department of Renal Medicine, Derby City General Hospital, Derby, UK, 2 Department of Radiology, Derbyshire Royal Infirmary, Derby, UK and 3 Centre for Integrated Systems Biology and Medicine, University of Nottingham, Nottingham, UK
Correspondence and offprint requests to: Dr C. W. McIntyre, Department of Renal Medicine, Derby City General Hospital, Uttoxeter Road, Derby, DE22 3NE, UK. Email: Chris.McIntyre{at}derbyhospitals.nhs.uk
Keywords: accessory renal arteries; cerebrovascular disease; hypertension; renal ectopia; renovascular disease
Case
Mr. G.L. aged 32 was referred to the Department of Renal Medicine at Derby City Hospital with unexplained hypertension. At 13 years of age he had suffered a cerebrovascular accident causing a left hemiparesis. At the time there were no risk factors identified to account for his stroke including normal intracerebral arteries. During his late teens he developed hypertension, which was controlled with Atenolol and Bendrofluazide. Three years prior to his referral to the Renal Department, he underwent investigation for hypertension revealing no evidence of secondary causes. An ultrasound scan at that time, showed two normal-sized kidneys but with the left kidney in a pelvic position.
Examination at referral was unremarkable with a blood pressure of 140/80 (on two antihypertensives) and negative urinalysis. Repeat ultrasound revealed a right kidney measuring 11.5 cm and the left pelvic kidney measuring 8.9 cm. The asymmetry of the kidneys raised the possibility of congenital renal artery abnormalities and therefore magnetic resonance angiography (MRA) of his renal arteries was undertaken.
This scan revealed a normal right renal artery. Three arteries were seen supplying the left pelvic kidney. One arose from the medial aspect of the right common iliac, one from the medial aspect of the left common iliac origin, and the third from the posterior aspect of the left common iliac artery. The arteries appeared attenuated but smooth walled. The middle artery arising from the medial aspect of the origin of the left common iliac artery was significantly stenosed at its origin. The other two arteries were attenuated but had no focal abnormality (Figures 1 and 2).
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Discussion
The permanent kidneys develop from the metanephric mesoderm and ureteric bud beginning development within the pelvis. Growth of the embryo caudal to the kidneys causes ascent of the kidneys. As the kidneys move more cranially, they receive their blood supply from vessels that lay in close proximity, initially the iliac vessels and then the aorta. These lower vessels often disappear.
Failure of proper ascent of the kidney occurs in 1 in 800 births. Such kidneys often maintain their fetal blood supply from the iliac vessels or the distal aorta. Accessory renal arteries are not uncommon occurring in some 1020% of patients [1].
Renal artery stenosis has long been accepted as a cause of hypertension. However, accessory arteries, as in our case often have a smaller caliber and no consensus exists on whether stenosis of the multiple smaller vessels leads to hypertension [2]. In addition angioplasty and/or stenting of these smaller caliber arteries is associated with a greater risk of complication and therefore it remains a matter of debate as to whether patients would benefit from intervention on these arteries [3].
Conflict of interest statement. None declared.
References
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