Unusual clinical presentations of bilateral renal artery aneurysms in a child. The value of ultrasound in diagnosis.

Abstract

The ultrasonic (US) diagnosis of bilateral renal artery aneurysms in children has not previously been described. At the age of 1 year a male child was diagnosed as suffering from hypogammaglobulinaemia (HGG). At the age of 7 years the child was admitted as an emergency with a tender left loin mass. Intravenous urography (IVU) and renal US demonstrated a left para-vertebral mass displacing the left kidney. (Fig. 1). A transonic area measuring 1 cm in diameter was noted in the supramedial part of the mass. The diagnosis was made of a partially necrotic abscess. At laparotomy extensive haemorrhage ensued necessitating a nephrectomy. Histology revealed the mass to represent an infected haematoma associated with a left renal artery aneurysm. In retrospect the transonic area on ultrasound almost certainly represented the aneurysm. At the age of 9 years the child developed systemic hypertension. Despite extensive biochemical and radiological investigations, including renin measurements and isotope scans, no definite cause was demonstrated for the hypertension. Due to poor medical control the child was re-admitted in May 1985 for further assessment. Initial screening with ultrasound demonstrated a normal sized fight kidney and a tubular structure with an echogenic rim casting an acoustic shadow was noted in the region of the fight renal hilum (Fig. 2). The appearances suggested a calcified renal artery aneurysm which was confirmed with plain film radiography and angiography. It was decided to treat the child conservatively with anti-hypertensive agents and to defer surgery. The use of US in the initial investigations of children with reno-vascular hypertension is now well established [1]. The diagnosis of bilateral renal artery aneurysms (RAA) with US has not been previously described. RAA are rare in children and more commonly present in adults in the 50-70 year age group. The incidence is stated to be 1% in a selected group of 8,525 patients undergoing renal angiography [2]. It is observed that aneurysms of the main renal artery or its extra-renal branches are commoner than intra renal aneurysms [3]. The three commonest causes of aneurysm formation in childhood are congenital, mycotic and secondary to vasculitis [3]. The latter condition is a feature of diffuse systemic diseases including polyarteritis nodosa, Kawasaki's and Takayashu's arteritis [3]. Other rare causes include trauma, neurofibromatosis, rubella, atherosclerosis and drug abuse (amphetamines) [4]. The last two conditions are extremely uncommon in childhood. Renal and intra renal aneurysms are associated with systemic hypertension in 76-87% of cases [2, 5], thrombosis, embolisation and rupture which is frequently fatal. The cause of the hypertension is hypoperfusion distal to the aneurysm which leads to activation of the renin/ angiotensin system [2]. In our case the cause of the aneurysms was thought to be due to infection as a complication of HGG. No stigmata of a generalised vasculitis was detected. We present an unusual case of bilateral renal artery aneurysms. We suggest that US should be used to identify abnormalities of the renal vessels and aorta in children with systemic hypertension. Angiography remains the definitive imaging modality for reno-vascular hypertension although Doppler US may be of value in the future. Acknowledgements. We would like to thank Miss Jennifer Anderson for typing this manuscript.