Massive proteinuria due to renal artery stenosis

A case report of successfully treated nephrotic syndrome after renal angioplasty

Background

The standard treatment of renovascular hypertension accompanying renal artery stenosis (RAS) consists of angioplasty and administration of antihypertensive medication. Although nephrotic syndrome (NS) has been reported to be associated with RAS, the development of NS after revascularization of RAS is extremely rare.

Case presentation

A 48-year-old man presented with uncontrolled hypertension and azotemia. The right kidney was atrophic, and RAS of the left kidney was suspected based on a post-captopril DTPA scan. His blood pressure stabilized after renal angioplasty; however, he complained of edema after 1 week. NS developed and was diagnosed as focal segmental glomerulosclerosis (FSGS) based on renal biopsy. He received an angiotensin receptor blocker. Proteinuria resolved after 1 year.

Conclusions

FSGS rarely develops after angioplasty of renal artery stenosis. This is the first report of successful treatment of this condition using an angiotensin receptor blocker during 1-year follow-up.

Neuroblastoma presenting with acute kidney injury, hyponatremic-hypertensive-like syndrome and nephrotic proteinuria in a 10-month-old child

Neuroblastoma is the most common extracranial solid tumor in childhood. Its presenting signs and symptoms may be highly variable, depending on the location of the primary tumor and its local or metastatic diffusion and, rarely, with paraneoplastic syndrome such as opsoclonus-myoclonus-ataxia syndrome and gastrointestinal disturbances, due to autoantibodies or to aberrant secretion of vasoactive intestinal peptide. Herein we describe a 10-month-old child with neuroblastoma presenting with a complex clinical picture characterized by acute kidney injury manifested by renal insufficiency and signs and symptoms of tubulointerstitial damage, with polyuria, polydipsia, glucosuria, aminoaciduria and hypochloremic metabolic alkalosis, and of glomerular damage with heavy proteinuria. Imaging study documented a suprarenal mass enveloping the aorta and its abdominal and renal ramifications and bilaterally renal veins. This clinical picture shows some analogies with the hyponatremic-hypertensive syndrome concerning the renovascular disease; however, in absence of systemic arterial hypertension, the heavy proteinuria and the polyuria could be explained by sectional increased intraglomerular pressure, due to local renal blood vessels constriction. Hypochloremic metabolic alkalosis probably developed because of local production of renin, responsible of renin-angiotensin-aldosterone system activation, but above all because of chloride loss through sweating. The long lasting dehydration, due to vomiting, sweating and polyuria, caused prolonged prerenal failure evolving in proximal tubular damage manifestations.

The hyponatremic hypertensive syndrome in a preterm infant: a case of severe hyponatremia with neurological sequels

Objective. To report the irreversible severe neurological symptoms following the hyponatremic hypertensive syndrome (HHS) in an infant after umbilical arterial catheterization. Design. Case report with review of the literature. Setting. Neonatal intensive care unit at a tertiary care children's hospital. Patient. A three-week-old preterm infant. Conclusions. In evaluating a neonate with hyponatremia and hypertension, HHS should be considered, especially in case of umbilical arterial catheterization. In case of diagnostic delay, there is a risk of severe irreversible neurological damage.

Renovascular hypertension: a unique cause of unilateral focal segmental glomerulosclerosis

A 48-year-old man presented with malignant hypertension and massive proteinuria. Renal angiography showed complete obstruction of the left renal artery and 99mTc-mercaptoacetylglycine (MAG3) renography showed a nonfunctioning left kidney. Percutaneous transluminal renal angioplasty of the left renal artery was unsuccessful; hence, the patient underwent left nephrectomy because of uncontrolled hypertension and proteinuria. Histological examination of a right kidney specimen revealed lesions of focal segmental glomerulosclerosis with benign nephrosclerosis. In contrast, histology of the left kidney showed typical ischemic kidney with hypertrophy of arteriolar smooth muscle cells. The patient responded favorably to the nephrectomy, as his blood pressure and urinary protein dramatically decreased with no antihypertensive medication. This case illustrates the heterogeneous effect of the renin-angiotensin system on either kidney in patients with renovascular hypertension due to unilateral renal artery stenosis.

Hyponatraemic-hypertensive syndrome in a 15-month-old child with renal artery stenosis

In this report we present the case of a 15-month-old girl with hyponatraemic-hypertensive syndrome (HHS) caused by stenosis of the left renal artery. On sonographic examination the contralateral non-stenotic kidney appeared enlarged and with cortical hyperechogenicity mimicking a parenchymal lesion. After successful percutaneous transluminal angioplasty, when the girl became normotensive, her serum electrolyte and acid-base balance became normal within a few days. The contralateral non-stenotic kidney hyperechogenicity also disappeared, but only after a period of 6 months, suggesting parenchymal damage due to tubulointerstitial injury, even though reversible. Our case confirms that renovascular hypertension may rarely also be present with HHS in children and that metabolic and morphological alterations are reversible after the resolution of arterial stenosis.

Proteinuria in renal artery occlusion is related to active renin concentration and contralateral kidney size

OBJECTIVES

Angiotensin II, in addition to having vasopressor effects, induces proteinuria in experimental models. Proteinuria has been reported, sometimes in the nephrotic range, in patients with chronic complete renal artery occlusion. We aimed to identify the factors associated with proteinuria in such cases. DESIGN AND MAIN OUTCOME MEASURE: Complete renal artery occlusion was detected by intra-arterial angiography in 96 patients referred for hypertension. We analysed patient characteristics at presentation to identify the factors associated with proteinuria.

SETTING

A referral hypertension unit.

RESULTS

Median protein excretion was 0.25 g/day (range 0-11). Nine patients had nephrotic syndrome (proteinuria >/= 3.5 g/day per 1.73 m2). Patients in the upper tertile for proteinuria differed from those with lower proteinuria in terms of total cholesterol levels (P < 0.01), the proportion of diabetics (P < 0.01) and supine active renin concentration (P = 0.02). They tended to have higher systolic blood pressure levels (P = 0.07), a lower frequency of contralateral renal artery stenosis (P = 0.09) and a longer contralateral kidney (P = 0.09). In multivariate logistic regression, the factors independently linked to proteinuria in the upper tertile were active renin concentration (P = 0.05) and contralateral kidney length (P = 0.02). Proteinuria significantly decreased in nephrotic patients (P < 0.01) treated with revascularization or nephrectomy and/or angiotensin converting enzyme inhibition.

CONCLUSIONS

Proteinuria in renal artery occlusion is positively related to active renin concentration, which reflects plasma angiotensin II concentration. Therapy aimed at lowering angiotensin II levels decreased proteinuria in nephrotic patients. The positive relationship between proteinuria and contralateral kidney length may reflect compensatory hypertrophy in response to nephron function loss.

Reversible renin mediated massive proteinuria successfully treated by nephrectomy

We report on a patient with severe hypertension and nephrotic range proteinuria, which were renin mediated in origin. Aortography demonstrated occlusion of the right renal artery and renal vein renin measurements lateralized strongly to the right kidney. Removal of the right kidney led to amelioration of hypertension and proteinuria. Massive proteinuria in this setting is due to high levels of intrarenal angiotensin II and is reversible with deactivation of the renin-angiotensin system.