A Case of Renovascular Hypertension Associated with Neurofibromatosis

Abstract

We report a case of renovascular hypertension associated with neurofibromatosis complicated by moderate proteinuria. A 16-year-old female was admitted to Kensei General Hospital with a complaint of headache and a blood pressure of 230/120 mm Hg. She was referred to us for further evaluation of the hypertension. On examination, cafe-au-lait spots were seen over her extremities and flank, and a bruit was heard in the right upper abdomen. The urinary protein excretion was 2.1 g/day. The plasma renin activity (PRA) and plasma aldosterone concentration were high, but the levels of catecholamines were normal. The renogram was asymmetric and on venous sampling, the PRA in the right renal vein was 58.3 ng/ml/h and that in the left was 22.1 ng/ml/h. CT scan detected an approximately 10-mm mass in the proximal right renal artery. Arteriography disclosed severe stenosis in the right renal artery and the superior mesenteric artery. Therefore, we concluded that her hypertension resulted from stenosis of the right renal artery due to neurofibromatosis. Accordingly, she underwent an operation to reconstruct that artery. After the operation, her blood pressure and PRA normalized without administration of any anti-hypertensive drug and urinary protein disappeared.

Renovascular disease and hypertension in children with neurofibromatosis

“…It is generally accepted that NF lesions respond poorly to PTA, presumably because of the tough fibrotic tissue involved that is refractory to dilatation [13,19,22,23]; poor results are sometimes obtained by PTA in middle-aortic syndrome and in ostial lesions [22,32]. Nonetheless, some authors have used this method in NF1 [3,5,9,15,16], and encouraging results (67% success rate) or at least temporary benefits were obtained. Our results, in accordance with other reports, suggest the use of this technique in patients with NF1 and vascular lesions.…”

“…Secondary hypertension may develop in NF1 as a result of pheochromocytoma; while it is a common etiology in adult patients, in pediatric patients elevated blood pressure is usually due to renal artery stenosis [8][9][10][11], generally involving the origin or the proximal tract of the vessel [3,5,6], and is associated in 25% of patients with coarctation of the abdominal aorta [5]. Several patients with NF1 and hypertension have been reported in the literature, showing the extreme variability in anatomical lesions [4,6], in clinical features, and in the different opinions concerning diagnostic procedures and management [3-5, 9, 12-15].…”

Blood pressure and cardiovascular involvement in children with neurofibromatosis type1

“…Few studies have been performed on the incidence of hypertension in NF1 patients; the majority of authors have described only single cases [11,13,14]. In NF1 children hypertension is usually caused by renal artery stenosis, which can be intrinsic, arising from arterial dysplasia, or extrinsic, due to neurofibroma or other abdominal mass compression [15,16].…”

Loss of GTPase activating protein neurofibromin stimulates paracrine cell communication via macropinocytosis

“…These findings prompted us to examine whether exosomes derived from AngII-treated endothelial cells are internalized by LysM Cre + / Nf1 flox/flox macrophages via macropinocytosis. In these experiments, we used AngII to stimulate wild type endothelial cell release of exosomes because a ) renal artery stenosis is associated with activation of the renin-angiotensin-aldosterone (RAAS) system in NF1 patients [40] and b ) AngII-infusion promotes aneurysm formation in animal models of neurofibromatosis [8]. Bone marrow-derived mesenchymal stem cells (MSC) (CD45 - /CD44 + ; Fig.…”