A London experience 1995-2012: demographic, dietary and biochemical characteristics of a large adult cohort of patients with renal stone disease.

BACKGROUND: Kidney stone disease has an estimated prevalence of around 10%. Genetic as well as environmental factors are thought to play an important role in the pathogenesis of renal stones. AIM: The aim of our study was to analyse and report the main characteristics of patients with kidney stones attending a large UK metabolic stone clinic in London between 1995 and 2012. DESIGN: A cross-sectional study. METHODS: Analysis of data from stone formers attending the University College and Royal Free Hospitals' metabolic stone clinic from 1995 to 2012. Demographic, clinical, dietary and biochemical characteristics have been summarized and analysed for men and women separately; trends over time have also been analysed. RESULTS: Of the 2861 patients included in the analysis, 2016 (70%) were men with an average age of 47 years (range 18-87 years) and median duration of disease of 6 years (range 0-60 years). The prevalence of low urine volume, hypercalciuria, hyperoxaluria, hyperuricosuria and hypocitraturia was 5.6%, 38%, 7.9%, 18% and 23%, respectively. The prevalence of several risk factors for stones increased over time. The majority of stones were mixed, with around 90% composed of calcium salts in varying proportion. CONCLUSION: Our findings in a large cohort of patients attending a London-based stone clinic over the past 20 years show differences in distributions of risk factors for stones for men and women, as well as metabolic profiles and stone composition. The impact of most risk factors for stones appeared to change over time.

Effect of eplerenone on blood pressure and the renin-angiotensin-aldosterone system in oligo-anuric chronic hemodialysis patients - a pilot study.

INTRODUCTION AND AIMS: Recent studies have suggested that aldosterone has many effects in addition to its ability to cause the kidney to retain sodium. To test the hypothesis that aldosterone can cause hypertension in a manner that does not involve renal sodium retention, we administered eplerenone, a specific aldosterone antagonist, to oligo-anuric chronic hemodialysis patients who had HTN. METHODS: 220 chronic hemodialysis patients underwent initial screening. Of these, 8 patients were followed for 8 weeks and their blood pressure, weight, plasma potassium, aldosterone levels and plasma renin activity were recorded. After a 4 week run in period, each patient received eplerenone 25 mg twice daily for another 4 weeks. RESULTS: Administration of eplerenone for 4 weeks decreased predialysis systolic blood pressure from 166 ± 14 to 153 ± 10 mmHg (p < 0.05). Eplerenone had no effect on diastolic blood pressure, potassium, predialysis weight, intradialytic weight gain, plasma aldosterone or PRA. CONCLUSION: Eplerenone significantly reduces systolic blood pressure in oligo-anuric hypertensive hemodialysis patients without effect on plasma aldosterone concentrations or plasma renin activity. Plasma potassium increases minimally after 4 weeks of therapy, a finding that raises some concern for long-term eplerenone use in chronic hemodialysis.

High dose urokinase for restoration of patency of occluded permanent central venous catheters in hemodialysis patients.

BACKGROUND: Catheter thrombosis is common and results in inadequate dialysis treatment and, frequently, in catheter loss. Since dialysis treatment runs on a strict schedule, occluded catheters need to be restored in a timely and cost effective manner. We present a new shortened protocol of urokinase infusion that allows hemodialysis to be performed within 90 minutes. METHODS: To chronic hemodialysis patients, who developed complete catheter occlusion, urokinase was infused simultaneously through both lumens of the catheter (125,000 units to each lumen) over 90 minutes. Technical success was defined as restoring blood pump speed to at least 250 ml/min. We determined the average time from catheter placement to first clot event (primary patency PP), recurrent clot event after urokinase treatment (secondary patency SP), catheter salvage rate and cause for removal. RESULTS: 37 catheters developed total thrombosis and urokinase was used to restore patency one or more times (total 47 treatments). Catheter salvage rate was 97 %. The average time of PP was 152 ± 56 days (7 - 784 days). Nine patients (30%) developed recurrent occlusion and the average time of SP was 64 ± 34 days (2 - 364 days). One catheter was removed because of dysfunction due to thrombosis. Other catheters were removed due to infection, fistula maturation or fell out spontaneously. Hemodialysis was performed immediately after treatment with blood speed of 250 ml/min in all patients. CONCLUSION: Our protocol is highly effective, short, and allows to restore patency of totally occluded central venous catheters with minimal disruption of the dialysis session.

Severe renal failure and microangiopathic hemolysis induced by malignant hypertension--case series and review of literature.

Malignant nephrosclerosis is acute renal failure in the setting of malignant hypertension and may be associated with thrombotic microangiopathy. Although the prognosis has improved considerably over the past decades, renal dysfunction remains an important cause of morbidity and mortality. Adequate control of blood pressure is crucial, allows gradual healing of the necrotizing vascular lesions and may induce stabilization and improvement of renal function in about 50 - 80% of involved patients. In addition, recent investigations have provided a better understanding of the pathophysiology of malignant hypertension and offer possibilities for identifying patients at risk. We report 3 patients who developed severe acute renal failure requiring dialysis initiation in the setting of malignant hypertension. All patients had kidney biopsy proven malignant nephrosclerosis and presented with symptoms of thrombotic microangiopathy. Despite adequate blood pressure control the prognosis of our patients varied.