Renin participation in hypertension associated with unilateral hydronephrosis

Sudden-onset hypertension leading to the diagnosis of unilateral hydronephrosis due to ureteropelvic junction obstruction

We present a case of a 41-year-old female who developed hypertension over a three-month period and was subsequently diagnosed with ureteropelvic junction obstruction (UPJO). The patient came to our department with elevated blood pressure. Blood examinations revealed normal renal function, hypokalemia and increased renin-angiotensin system (RAS) activity, as indicated by elevated level of plasma renin activity and plasma aldosterone level. A computed tomography imaging further revealed dilation of the left renal pelvis, atrophy of the left kidney, and indications of obstruction at the junction between the renal pelvis and ureter. Surgical intervention in the form of a left pyeloplasty successfully resolved the unilateral hydronephrosis, corrected the elevated RAS activity, normalized the blood pressure, and ameliorated the hypokalemia. This case emphasizes that elevated blood pressure might be the sole clinical indication of hydronephrosis. It's crucial to consider hydronephrosis due to UPJO as a potential cause, especially when diagnosing hypertension associated with RAS hyperactivity in young adults. It also highlights the effectiveness of surgical intervention in treating hypertension in such scenarios.

Renal tamponade in a patient with hydronephrosis-related Page kidney

A 48-year-old woman presented with hyperreninemic hypertension and renal dysfunction and was diagnosed with hydronephrosis-related Page kidney. The pathophysiology was "renal tamponade", in which the kidney was compressed by the renal pelvis and Gerota's fascia, resulting in intrarenal microvascular ischemia. Ureteral stent placement promptly improved the hyperreninemic hypertension and renal dysfunction, and additional perirenal fluid drainage gradually improved these conditions. These observations indicated the following three points. First, renal compression-induced renin-angiotensin-aldosterone system upregulation plays an important role in the pathogenesis of Page kidney. Second, physicians should consider perirenal fluid drainage as a therapeutic option in addition to ureteral stenting in patients with hydronephrosis-related Page kidney. Third, bilateral perirenal subcapsular hematomas in this case could be caused by hydronephrosis. Hydronephrosis-induced intrarenal pressure elevation possibly caused chronic perirenal subcapsular hemorrhage at the vulnerable sites of the renal cortex and peeling of the renal capsule from the cortex, resulting in the bilateral massive subcapsular hematomas and Page kidney.

Percutaneous management of ureteropelvic junction obstruction

PURPOSE OF REVIEW

The development of endoscopic and minimally invasive techniques has revolutionized the treatment of ureteropelvic junction obstruction (UPJO). Patients can now undergo successful UPJO repair without the morbidity and complications associated with open surgery. Laparoscopic and robotic repair has supplanted open surgery as the gold standard, but percutaneous endoscopic treatment remains a relevant alternative to more invasive surgery. This review will focus on the percutaneous approach for the treatment of UPJO.

RECENT FINDINGS

Percutaneous endopyelotomy was popularized during the 1980 s due to advances in the field of endourology, allowing for well tolerated and reliable percutaneous access to the kidney. After percutaneous access to the kidney is achieved, the narrowed ureter at the UPJ is incised in a full thickness fashion in the posterolateral position from the ureteral lumen to the periureteral fat. Success rates for this procedure are nearly 90% at high-volume centres. The ideal patient who has success with percutaneous endopyelotomy has a short segment of narrowing less than 2 cm, no crossing vessel, good ipsilateral renal function and mild hydronephrosis.

SUMMARY

Although the development of laparoscopic and robotic approaches to pyeloplasty has produced outcomes that surpass those of percutaneous endopyelotomy, it remains a viable option in the appropriately selected patient, but success rates tend to decrease with longer follow up.

Laparoscopic pyeloplasty practice patterns in Canada

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is a condition characterized by partial or complete obstruction of urine transport from the renal pelvis to the ureter and can present with intermittent flank pain, recurrent urinary tract infections, renal stones, or renal dysfunction. While historically, open pyeloplasty was the gold standard for surgical management, laparoscopic methods to repair UPJO have largely taken over as the preferred approach for adolescent and adult patients. Despite near universal adoption of laparoscopic pyeloplasty among Canadian urologists, it remains a technically complex procedure and considerable variability exists in the procedural steps performed.

METHODS

An online survey was distributed to all urologists registered with the Canadian Urology Association (CUA). Participants were asked to describe their training background, comfort level with laparoscopic pyeloplasty, positioning preferences, procedural steps, and stenting practices.

RESULTS

A total of 100 board-certified urologists completed our survey, with approximately half from a community setting and half with academic affiliations (56% and 43%, respectively). The vast majority (98%) reported preferring the Anderson-Hynes (dismembered) pyeloplasty technique. Other technical steps of the procedure were variable among respondents, with no discernable pattern. Those who felt most comfortable with the procedure tended to perform a larger volume of laparoscopic pyeloplasties annually or work at higher-volume institutions.

CONCLUSIONS

Laparoscopic pyeloplasty remains a technically challenging procedure that many Canadian urologists are uncomfortable performing. With this publication, we hope to create discussion among urologists and to reveal procedural tips that may improve comfort in tackling these complex cases.

Hydronephrosis and risk of later development of hypertension

AIM

Congenital ureteral obstruction is a fairly common condition in infants, and its clinical management has been long debated during the last decade. The long-term physiological consequences of today's conservative non-surgical management in many asymptomatic hydronephrotic children are unclear.

METHODS

Experimental studies in rats and mice, retrospective studies in children and adults, as well as prospective studies in children are included in this mini review.

RESULTS

Experimental models of hydronephrosis in rats and mice have demonstrated that partial ureteropelvic junction obstruction (UPJO) is casually linked with development of hypertension and renal injuries in later life. The mechanisms are multifactorial and involve increased activity of the renin-angiotensin-aldosterone system and renal sympathetic nerve activity. Furthermore, oxidative stress and nitric oxide deficiency in the affected kidney appear to play important roles in the development and maintenance of hypertension. Clinical case reports in adults and recent prospective studies in children have associated hydronephrosis with elevated blood pressure, which could be reduced by surgical management of the obstruction.

CONCLUSION

Based on current experimental and clinical knowledge regarding the link between partial UPJO and changes in blood pressure, it is proposed that today's non-operative management of hydronephrosis should be reconsidered to reduce the risk of developing elevated blood pressure or hypertension in later life.

Hypertension in infancy: diagnosis, management and outcome

Advances in the ability to identify, evaluate, and care for infants with hypertension, coupled with advances in the practice of Neonatology, have led to an increased awareness of hypertension in modern neonatal intensive care units. This review will present updated data on blood pressure values in neonates, with a focus on the changes that occur over the first days and weeks of life in both term and preterm infants. Optimal blood pressure measurement techniques as well as the differential diagnosis of hypertension in the neonate and older infants will be discussed. Recommendations for the optimal immediate and long-term evaluation and treatment, including potential treatment parameters, will be presented. We will also review additional information on outcome that has become available over the past decade.

Bilateral ureteropelvic junction obstruction presenting with hypertension and cerebral vascular accident

Cerebrovascular accident and renal hypertension secondary to ureteropelvic junction obstruction (UPJO) are extremely rare. A 6-year-old girl presented with intracranial hemorrhage because of hypertension secondary to the bilateral UPJO. This was successfully treated with craniotomy and subsequent percutaneous nephrostomy placement and bilateral pyeloplasty. Brain computerized tomography revealed right-sided intracranial hemorrhage, and renal ultrasonography confirmed bilateral severe hydronephrosis. Craniotomy with evacuation of intracerebral hematoma and bilateral nephrostomy under ultrasound guidance were performed. One week later, she underwent bilateral pyeloplasty in 2 stages. The patient has been well with normalized renal function and is completely cured of her hypertension in long-term follow-up.

Hydronephrosis causes salt-sensitive hypertension in rats

BACKGROUND

Hypertension is a common disease in the Western world and approximately 5% of all cases are secondary to kidney malfunction. It is not clear whether unilateral hydronephrosis due to partial obstruction affects blood pressure.

AIM

The aim of this study was to determine whether hypertension develops and to investigate the effects of different salt diets on the blood pressure in hydronephrotic animals.

METHODS

Unilateral partial ureteral obstruction was created in 3-week-old Sprague-Dawley rats. A telemetric device was implanted 4-6 weeks later and blood pressure was measured on normal, low- and high-salt diets. Plasma samples were collected on all diets for renin analysis.

RESULTS

All hydronephrotic animals developed hypertension that correlated to the degree of hydronephrosis. The blood pressure increased slowly with time and was salt sensitive. In severe hydronephrosis, blood pressure increased from 118 +/- 5 mmHg on low salt to 140 +/- 6 mmHg on high salt intake, compared to control levels of 82 +/- 2 and 84 +/- 2 mmHg, respectively. Plasma renin concentration was increased in the hydronephrotic group of animals compared to controls on all diets, but the difference was only significant on a normal salt diet, 165 +/- 15 versus 86 +/- 12 microGU/ml respectively. In animals with severe hydronephrosis the plasma renin levels were lower, and the changes less, than in those with mild and moderate hydronephrosis.

CONCLUSION

This study demonstrates the presence of a salt-sensitive hypertension in hydronephrosis. A systemic effect of the renin-angiotensin system alone cannot be responsible for the hypertension.

Ureteropelvic Junction Obstruction: Some new Acquisitions about Etiology, Pathophysiology and Diagnostics

The etiopathogenesis of uretero-pelvic junction obstruction (UPJO) has been the subject of many speculations and it remains, in some ways, a debatable matter. Some recently reported thorough research refer to neuro-mediated pathogenetic mechanisms rather than (or together with) myogenic ones.

Advances in US, radioisotopic functional imaging, CT and RM contribute to differentiate the obstructive conditions from the non-obstructive ones and to afford today a better assessment of renal functional damage. Particularly, diuretic renography is a non-invasive test for characterization of the renal functional abnormalities resulting from UPJO. Helical CT with angiography is a useful technique for identification of crossing vessels (pyelo-vascular tangle) which can be used for the pre-surgical planning of endopyelotomy. Endoluminal ultrasonography can be used to guide the position of the incision for endopyelotomy (US-guided endopyelotomy).

Laboratory examinations are important to determine the overall renal function (serum creatinine, acid-base balance, serum electrolytes, etc.), urinary MCP-1 and NAG (markers of tubular damage), and to rule out urinary tract infections.

The management of UPJO (watchful waiting; either open or laparoscopic dismembered pyeloplasty; endoluminal procedures) is greatly influenced by the diagnostic evaluation.

The paper aims to outline the advances in both physiopathology and diagnostics of UPJO on the basis of a review of the literature.

[Hydronephrosis arterial hypertension. Report of 4 cases]

Four cases of ureteropelvic junction syndrome associated with arterial hypertension were reported. The authors discuss the ethiopathogenic of hypertension, on the basis of these observations and a review of the literature. They conclude that union bilateral hydronephrosis can lead to hypertension and renal failure by both inappropriate production of renin and water chronic retention. The correction of ureteropelvic junction should return blood pressure to normal levels.

Hypertension and pulmonary oedema due to hyperreninemia - an uncommon presentation of blunt abdominal trauma

We present an uncommon case of a child with acute abdominal signs, hypertension and pulmonary oedema, following blunt abdominal trauma. The clinical picture was due to rupture of a renal cyst and excess renin secretion from a unilateral, obstructed hydronephrotic kidney. Three months after nephrectomy the patient was normotensive.

Management of children with hypertension from reflux or obstructive nephropathy

During a ten-year period, 35 children presenting with vesicoureteral reflux, ureteropelvic junction obstruction, or a "small kidney" were found to be hypertensive. Of these, 15 subsequently underwent surgical procedures for relief of hypertension. Seven were "cured," six were "improved," and two were "unchanged." The severity of hypertension could not be correlated with the degree of reflux nor with the degree of obstructive uropathy. However, all children with reflux in our study who were hypertensive had some degree of calicectasis noted preoperatively on intravenous pyelogram. Also it was noted that hypertension may occur several years after successful anti-reflux surgery. Children with vesicoureteral reflux, ureteropelvic junction obstruction, or a small kidney need to have blood pressure determinations at regular intervals, even if all previous readings had been in the normotensive range and whether or not they were followed up medically or post surgically. We suggest that blood pressure determinations be made every three months for the first year after diagnosis of reflux or ureteropelvic junction obstruction, and at least once a year thereafter.

Hypertension associated with unilateral hydronephrosis as a complication of Crohn's disease

Obstructive uropathy with hydronephrosis is a well-known complication of Crohn's disease. The treatment for this condition is still controversial. This is the case study of a 14-year-old girl with documented right-sided obstructive uropathy secondary to Crohn's disease associated with renin-mediated hypertension secondary to her obstructive uropathy. The patient had complete resolution of her hypertension following surgery, which involved only resection of the involved bowel without ureterolysis.

The pattern of plasma renin activity and aldosterone system in patients with sustained hydronephrosis

Twenty-six patients with unilateral and bilateral hydronephrosis were subjected to investigation to identify the patterns of PRA-aldosterone system. The incidence of hypertension in the unilateral group was 28.5%, while in the bilateral group it was 50%; the overall incidence was 34.6%. In the hypertensive patients (9 cases), plasma renin activity and aldosterone were normal in one, and elevated in three. Aldosterone only was elevated in 3 cases, while PRA was elevated in 2. In the normotensive patients, the levels of PRA and aldosterone were normal in 5 patients, while in the remaining 12 cases one or both parameters were elevated.

Imaging techniques in the evaluation of pediatric hypertension

Moderate or severe hypertension occurs in a small percentage of hypertensive children, but it is within this group that the surgically correctable causes of hypertension are found. Since cure rates up to 90% have been reported, it is important to diagnose a secondary cause of hypertension. Excretory urography is recommended to screen for renovascular hypertension and renal parenchymal disease. Renal scintigraphy can be substituted for the urogram, but the anatomical resolution is poorer. If renovascular hypertension is suggested by abnormal results of screening examination, arteriography should be part of the evaluation. Ultrasonography is reserved primarily for evaluating neonatal hypertension which most frequently is related to thrombosis. If this diagnosis is documented, renal function should be assessed with radionuclide techniques. If a hormonally active tumor is suspected, evaluation of the adrenals and retroperitoneum is accomplished best by CT.

Hypertension and unilateral hydronephrosis

We report 2 cases of hypertension associated with unilateral hydronephrosis. Lateralization of renal vein renins and exaggerated hyperreninemia following captopril suggested renin-mediated hypertension in 1 case, which responded well to nephrectomy.

Subcapsular urinoma: unusual form of "page kidney" in newborn

The first case of renal hypertension resulting from a urinoma in a kidney secondary to vesicoureteral reflux from posterior urethral valves in a newborn is presented. High-pressure reflux resulted in formation of a subcapsular urinoma. Removal of the nonfunctioning "Page kidney" cured the persistent hypertension.

Congenital ureteral valves: report of 2 patients, including one with a solitary kidney and associated hypertension

We report 2 cases of congenital ureteral valves treated successfully by excision of the involved segment and ureteroureterostomy. Hypertension in 1 patient and recurrent urinary tract infection in the other prompted initial evaluation. In the hypertensive patient renin collections from the vena cava and the renal vein of the solitary kidney were normal. Nevertheless, relief of obstruction has resolved the hypertension for 3 years. We review the literature regarding ureteral valves and discuss the mechanism by which unilateral hydronephrosis probably produces hypertension.