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1/495. Gross hematuria of uncommon origin: the nutcracker syndrome.

    Left renal vein hypertension, also called "nutcracker phenomenon" or "nutcracker syndrome," is a rare vascular abnormality responsible for gross hematuria. The phenomenon is attributable to the idiopathic decrease in the angle between the aorta and the superior mesenteric artery with consequent compression of the left renal vein. The entrapment of the left renal vein is not easily detectable by ordinary diagnostic procedures. We report two cases of gross hematuria (persistent in one patient and recurrent in the other) caused by "nutcracker phenomenon." In both cases, no remarkable findings were obtained from medical history, urinary red blood cells morphology, repeated urinalysis, pyelography, cystoscopy, or ureteroscopy. Left renal vein dilation in one case was found with a computed tomography (CT) scan performed on the venous tree of left kidney. The diagnosis of "nutcracker phenomenon" was confirmed by renal venography with measurement of pressure gradient between left renal vein and inferior vena cava in both cases. In one case, the diagnosis was complicated by the presence of mycobacterium tuberculosis in urine. The "nutcracker phenomenon" is probably more common than thought. early diagnosis is important to avoid unnecessary diagnostic procedures and complications such as the thrombosis of the left renal vein. Many procedures are available to correct the compression of the left renal vein entrapped between the aorta and the superior mesenteric artery: Gortex graft vein interposition, nephropexy, stenting, and kidney autotransplantation. After surgery, gross hematuria ceases in almost all patients. ( info)

2/495. Hypotensive response to captopril: a potential pitfall of scintigraphic assessment for renal artery stenosis.

    A characteristic pattern seen on captopril renography is described that is due to systemic hypotensive response. Most patients with these findings on captopril renography do not receive renal artery angiograms in our clinic because it is usually recognized. However, this pattern has received little attention in the medical literature and may be misinterpreted as being due to physiologically significant renal artery hypertension. methods: Over the last 3 y, renal artery angiograms were performed on three patients with systemic hypotensive response pattern on captopril renography. This allowed a unique opportunity to correlate the results of the captopril renogram with the renal artery angiograms in this patient population. captopril renography was performed with a glomerular filtration agent, diethylenetriamine pentaacetic acid (DTPA), and a tubular agent, o-iodohipurate (OIH). RESULTS: renal artery angiograms showed no evidence of renal artery stenosis in three patients with systemic hypotensive response pattern on captopril renography. Systemic hypotension on captopril renograms results in preserved uptake of both DTPA and OIH and hyperconcentration in the cortex and collecting system. CONCLUSION: The systemic hypotensive response pattern seen on captopril renography is a distinctive pattern that does not represent physiologically significant renal artery stenosis. ( info)

3/495. Iliorenal bypass for the treatment of type-3 Takayasu's disease. A case report with 10-year follow-up.

    The case of a 16-year old female with severe renovascular hypertension resulting from type-3 Takayasu's arteritis is reported. The entire thoracic and abdominal aorta was affected by an active inflammatory process and all its branches were stenotic or occluded. After the early failure of a percutaneous balloon angioplasty of the left renal artery, an iliac to renal artery bypass graft using a reversed autologous saphenous vein was performed through a retroperitoneal tunnel The patient is asymptomatic and the graft is patent at 10-year follow-up. ( info)

4/495. Solitary renal myofibromatosis: an unusual cause of infantile hypertension.

    INTRODUCTION: Renovascular disease accounts for the vast majority of cases of infantile hypertension with complications resulting from umbilical arterial catheterization predominating in the neonatal period and fibrodysplastic lesions of the renal artery predominating outside the neonatal period. We report a previously undescribed cause of renovascular hypertension: solitary renal myofibromatosis. CASE REPORT: A 9-month-old male infant was transported to the intensive care unit at Children's Hospital in Denver, colorado, for evaluation and treatment of a dilated cardiomyopathy and severe systemic hypertension. The child was full-term with no perinatal problems. Specifically, the child never required umbilical arterial catheterization. He was well until 6 months of age when his parents noted poor weight gain. At 9 months of age, he was evaluated at the referral hospital for failure to thrive. On examination he was noted to have a blood pressure of 170/110 mm Hg, but no other abnormalities. A chest radiograph showed cardiomegaly. Laboratory studies demonstrated normal electrolytes, blood urea nitrogen, and creatinine. However, urinalysis demonstrated 4 protein without red blood cells. An echocardiogram showed severe left ventricular dilatation with an ejection fraction of 16%. On admission the child was noted to be cachectic. His vital signs, including blood pressure, were normal for age. The physical examination was unremarkable. serum electrolytes, blood urea nitrogen, and creatinine were normal. Echocardiographic studies suggested a dilated hypertrophic cardiomyopathy. He was started on digoxin and captopril. Subsequently, he demonstrated episodic hypertension ranging from 170/90 to 220/130 mm Hg. A repeat echocardiogram 24 hours after admission demonstrated a purely hypertrophic cardiomyopathy. verapamil and nifedipine were added to the treatment regimen in an effort to better control the blood pressure without success. urine and blood for catecholamines and plasma renin activity, respectively, were sent and treatment with phentolamine instituted because of a possible pheochromocytoma. A spiral abdominal computerized tomographic scan revealed a markedly abnormal right kidney with linear streaky areas of calcification around the hilum and also an area of nonenhancement in the posterior upper pole. The adrenals and the left kidney were normal. Doppler ultrasound revealed a decrease in right renal arterial flow. The urinary catecholamines were normal and surgery was scheduled after the blood pressure was brought under control by medical treatment. At surgery, tumorous tissue and thrombosis of the renal artery were found in the right upper pole. A right nephrectomy was performed. Pathologic examination of the kidney showed the presence of a diffuse spindle cell proliferation in the interstitium of the kidney. The angiogenic/angiocentric character of the proliferation was demonstrated in several large renal vessels. The lumen of most vessels was narrowed and some vessels were totally occluded with recanalization and dystrophic calcifications observed. Immunostaining of the tumor demonstrated strong desmin and vimentin positivity and minimal actin positivity in the spindle cells. Mitotic activity was not noted in the spindle cell process. These pathologic changes were consistent with a diagnosis of infantile myofibromatosis (IM). The child's preoperative plasma renin activity was 50 712 ng/dL/h (reference range, 235-3700 ng/dL/h). DISCUSSION: The causes of systemic hypertension in infancy are many although renal causes are by far the most common. Renal arterial stenosis or thrombosis accounts for 10% to 24% of cases of infantile hypertension. renal artery thrombosis is usually a consequence of umbilical arterial catheterization, which can also lead to embolization of the renal artery. renal artery stenosis may result from fibrodysplastic lesions (74%), abdominal aortitis (9%), a complication of renal transplantation (5%), and ren ( info)

5/495. Radionuclide renography: a personal approach.

    Recent advances have increased the value of radionuclide renography in evaluating the patient with suspected disease of the genitourinary tract. The use of the consensus process to help standardize procedures and recommend interpretative criteria provides guidance for the nuclear medicine practitioner, serves as a basis to improve the standard of practice, and facilitates pooling of data from different centers. This review draws on the consensus criteria to present a personal approach to radionuclide renography with a particular emphasis on diuresis renography and the detection of renovascular hypertension. patients are encouraged to come well hydrated and void immediately prior to the study. Our standard radiopharmaceutical is 99mTc mercaptoacetyltriglycine (MAG3). Routine quantitative indices include a MAG3 clearance, whole kidney and cortical (parenchymal) regions of interest, measurements of relative uptake, time to peak height (Tmax), 20 min/max count ratio, residual urine volume and a T(1/2) in patients undergoing diuresis renography. A 1-minute image of the injection site is obtained at the conclusion of the study to check for infiltration because infiltration can invalidate a plasma sample clearance and alter the renogram curve. A postvoid image of the kidneys and bladder is obtained to calculate residual urine volume and to better evaluate drainage from the collecting system. In patients undergoing diuresis renography, the T(1/2) is calculated using a region of interest around the activity in the dilated collecting system. A prolonged T(1/2), however, should never be the sole criterion for diagnosing the presence of obstruction; the T(1/2) must be interpreted in the context of the sequential images, total and individual kidney function, other quantitative indices and available diagnostic studies. The goal of ACE inhibitor renography is to detect renovascular hypertension, not renal artery stenosis. patients with a positive study have a high probability of cure or amelioration of the hypertension following revascularization. In patients with azotemia or in patients with a small, poorly functioning kidney, the test result is often indeterminate (intermediate probability) with an abnormal baseline study that does not change following ACE inhibition. In patients with normal renal function, the test is highly accurate. To avoid unrealistic expectations on the part of the referring physician, it is often helpful to explain the likely differences in test results in these two-patient populations prior to the study. ( info)

6/495. Revascularization of a thrombosed, previously stented aorto-renal graft using combined directional atherectomy and AngioJet thrombectomy.

    We report an interesting case with bilateral PTFE aorto-renal grafts of which one graft underwent balloon angioplasty and stenting for proximal stenosis. Combined debulking by AngioJet thrombectomy and Simpsons directional atherectomy was performed within the stent following reocclusion of the graft 9 months later. ( info)

7/495. Negative captopril renography on patients with renin mediated hypertension due to page kidney and reninoma.

    Through a mechanism similar to renal artery stenosis, patients with reninoma and page kidney also suffered from renin mediated hypertension. captopril renograms performed on our patients with the latter two conditions, however, did not yield diagnostic findings. Therefore, equivocal or negative captopril renography cannot serve to rule out conditions with elevated renin other than renal artery stenosis. ( info)

8/495. Autotransplantation and stent implantation for bilateral renal artery fibromuscular dysplasia.

    A 36-yr-old male was found to have renovascular hypertension due to an occluded right renal artery and 70% stenosis in the left renal artery, caused by fibromuscular dysplasia. The right kidney was supplied by collateral blood flow, and secreted more renin than the left kidney. Two differential therapeutic approaches were taken: autotransplantation for the right kidney and percutaneous transluminal renal angioplasty followed by stent implantation for the left. The renovascular hypertension was treated with these therapies, preserving renal function in this patient. ( info)

9/495. Detection of renovascular hypertension: saralasin test versus renin determinations.

    Angiotensin blockade was established in hypertensive patients with the competitive inhibitor saralasin and the blood pressure response was compared to prior renin determinations. Two patients with subsequently confirmed renovascular hypertension had normal peripheral renin and non-lateralizing renal vein renin ratios, yet both showed a clear-cut lowering of blood pressure after administration of the blocking agent, indicating the presence of renin-mediated hypertension. Thus, direct in vivo testing with saralasin appears to offer certain advantages over renin determinations. ( info)

10/495. Percutaneous transluminal coronary angioplasty for renovascular hypertension in a child: a case report.

    Since its introduction, percutaneous transluminal coronary angioplasty has become an alternative therapeutic modality to surgical and medical treatment for renovascular hypertension. We report the case of a nine-year-old boy who had hypertension caused by renal arterial stenosis. The patient's high blood pressure was 164/100 mmHg, which was discovered incidentally during a physical check-up. A selective renal angiography showed a severe short-segment stenosis with post-stenotic dilatation of the left renal artery. A 4-mm balloon catheter was advanced through the stenotic area and was inflated five times to dilate the stenosis. After the procedure, the selective renal angiography showed a significant increase in the diameter of the left renal artery. blood pressure decreased to normal immediately after the procedure. During the one-year follow-up period, the patient remained normotensive without the use of antihypertensive drugs. ( info)
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