Faculty Bibliography

BACKGROUND: Patients with nephrolithiasis and hyperoxaluria generally are advised to follow a low-oxalate diet. However, most people do not eat isolated nutrients, but meals consisting of a variety of foods with complex combinations of nutrients. A more rational approach to nephrolithiasis prevention would be to base dietary advice on the cumulative effects of foods and different dietary patterns rather than single nutrients. STUDY DESIGN: Randomized controlled trial. SETTING & PARTICIPANTS: Recurrent stone formers with hyperoxaluria (urine oxalate > 40mg/d). INTERVENTION: The intervention group was asked to follow a calorie-controlled Dietary Approaches to Stop Hypertension (DASH)-style diet (a diet high in fruit, vegetables, whole grains, and low-fat dairy products and low in saturated fat, total fat, cholesterol, refined grains, sweets, and meat), whereas the control group was prescribed a low-oxalate diet. Study length was 8 weeks. OUTCOMES: Primary: change in urinary calcium oxalate supersaturation. SECONDARY: Changes in 24-hour urinary composition. RESULTS: 57 participants were randomly assigned (DASH group, 29; low-oxalate group, 28). 41 participants completed the trial (DASH group, 21; low-oxalate group, 20). As-treated analysis showed a trend for urinary oxalate excretion to increase in the DASH versus the low-oxalate group (point estimate of difference, 9.0mg/d; 95% CI, -1.1 to 19.1mg/d; P=0.08). However, there was a trend for calcium oxalate supersaturation to decrease in the DASH versus the low-oxalate group (point estimate of difference, -1.24; 95% CI, -2.80 to 0.32; P=0.08) in association with an increase in magnesium and citrate excretion and urine pH in the DASH versus low-oxalate group. LIMITATIONS: Limited sample size, as-treated analysis, nonsignificant results. CONCLUSIONS: The DASH diet might be an effective alternative to the low-oxalate diet in reducing calcium oxalate supersaturation and should be studied more.

Cystinuria is a genetic cause of recurrent kidney stones which may be more recurrent and larger than more common non-cystine stones. They may have a greater impact on health-related quality of life (HRQoL). We measured this impact by surveying HRQoL in patients with stones, comparing non-cystine stone formers (NCSF) to cystine stone formers (CYSF) and both groups to normative values of the US population. We used SF-36v2 via an internet instrument. CYSF patients were recruited via cystinuria-related websites, two patient advocacy groups, and an active endourology practice. NCSF patients were recruited from the same practice and by email. Total n surveyed with scorable data: 214 CYSF and 81 NCSF. The participants included 128 men and 161 women. The group of CYSF were significantly younger (39 vs. 54 years) and suffered longer from kidney stones (255 vs. 136 months). CYSF patients had significantly more episodes of stones than NCSF patients in the last year (N = 108 CYSF, N = 20 NCSF). More frequent stones in the last year and mental comorbidities most often predicted worse scores in the individual HRQoL domains. However, cystine stone composition was a significant predictor of worse scores only for role emotional. Better scores in all SF-36 domains were associated with greater time since the last kidney stone event. Although kidney stones are often transient, kidney stone formers, regardless of stone composition, have a worse HRQoL than the standard US population, which has a normative score of 50, such as general health (41.2 +/- 12.8), bodily pain (46.5 +/- 11.8) and mental health (45.1 +/- 12.6). CYSF are more frequent and severe stone formers compared with NCSF with a resulting greater, direct impact on the HRQoL of CYSF patients. Whether preventive strategies for cystinuria are being properly utilized by practitioners, and which strategies are most effective, should be established.

Context. Ingestion of glyphosate-surfactant herbicides (GlySH) can result in acute kidney injury, electrolyte abnormalities, acidosis, cardiovascular collapse, and death. In severe toxicity, the use of hemodialysis is reported, but largely unsupported by kinetic analysis. We report the dialysis clearance of glyphosate following a suicidal ingestion of a glyphosate-containing herbicide. Case details. A 62-year-old man was brought to the emergency department (ED) 8.5 h after drinking a bottle of commercial herbicide containing a 41% solution of glyphosate isopropylamine, in polyoxyethyleneamine (POEA) surfactant and water. He was bradycardic and obtunded with respiratory depression necessitating intubation and mechanical ventilation. Initial laboratory results were significant for the following: pH, 7.11; PCO2, 64 mmHg; PO2, 48 mmHg; potassium, 7.8 mEq/L; Cr 3.3, mg/dL; bicarbonate, 22 mEq/L; anion gap, 18 mEq/L; and lactate, 7.5 mmol/L. Acidosis and hyperkalemia persisted despite ventilation and fluid resuscitation. The patient underwent hemodialysis 16 h post ingestion, after which he demonstrated resolution of acidosis and hyperkalemia, and improvement in clinical status. Serum glyphosate concentrations were drawn prior to, during, and after hemodialysis. The extraction ratio and hemodialysis clearance were calculated to be 91.8% and 97.5 mL/min, respectively. Discussion. We demonstrate the successful clearance of glyphosate using hemodialysis, with corresponding clinical improvement in a patient with several poor prognostic factors (advanced age, large volume ingested, and impaired consciousness). The effects of hemodialysis on the surfactant compound are unknown. Hemodialysis can be considered when severe acidosis and acute kidney injury complicate ingestion of glyphosate-containing products.

Central venous stenosis is a well-described sequel to the placement of hemodialysis catheters in the central venous system. The presence of an ipsilateral arteriovenous fistula or graft often leads to severe venous dilatation, arm edema and recurrent infections. Vascular access thrombosis, compromised blood flow and inadequate dialysis delivery are dreaded complications that eventually render the access unusable. We report the case of a 58-year-old male hemodialysis patient who developed symptomatic central venous stenosis to illustrate the problem and review the pertinent literature. This patient developed severe enlargement of upper extremity veins due to central venous stenosis. The symptoms were refractory to multiple endovascular interventions and eventually necessitated ligation of his arteriovenous fistula. Central venous stenosis remains a pervasive problem despite advances in our understanding of its etiology and recognition of the enormity of its consequences. Due to the lack of effective therapeutic options, prevention is better than cure.

This review consolidates knowledge regarding the extensive genitourinary pathology experienced by taxi cab drivers. Taxi cab, livery, truck, and other drivers all objectively and subjectively may have more voiding dysfunction, infertility, urolithiasis, bladder cancer, and urinary infections as compared with nonprofessional drivers; this is called taxi cab syndrome. Together with governmental and medical assistance, simple interventions-such as education, the addition of taxi relief stations, and possibly the use of sanitary urinary collection devices-to curb the progression of genitourinary disease in taxi drivers should be prospectively studied. It is postulated that many of these interventions may also benefit other groups of occupationally related infrequent voiders.

Chronic kidney disease (CKD) is an important clinical co-morbidity that increases the risk of death and myocardial infarction in patients with coronary artery disease (CAD) even when treated with guideline-directed therapies. It is unknown, however, whether CKD influences the effects of CAD treatments on patients' health status, their symptoms, function, and quality of life. We performed a post hoc analysis of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) study to compare health status in patients with stable CAD with and without CKD defined as a glomerular filtration rate of <60 ml/min/1.73 m(2) randomized to either percutaneous coronary intervention (PCI) and optimal medical therapy (OMT) or OMT alone. Health status was measured at baseline, 1, 3, 6, 12, 24, and 36 months of follow-up with the Seattle Angina Questionnaire in 310 patients with CKD and 1,719 patients without CKD. Linear mixed-effects models were used to analyze Seattle Angina Questionnaire scores longitudinally. Mean scores for angina-related quality of life, angina frequency, and physical limitation domains improved from baseline values in both patients with and without CKD and plateaued. Early improvement (1 to 6 months) was more common in patients treated with PCI plus OMT than with OMT alone in both patients with and without CKD. Treatment satisfaction scores were high at baseline in all groups and did not change significantly over time. In conclusion, although CKD is an important determinant of event-free survival in patients with stable CAD, it neither precludes satisfactory treatment of angina with PCI plus OMT or OMT alone nor is it associated with an unsatisfactory quality of life.

The 2012 KDIGO (Kidney Disease: Improving Global Outcomes) Clinical Practice Guideline for Anemia in Chronic Kidney Disease provides clinicians with comprehensive evidence-based recommendations to improve patient care. In this commentary, we review these recommendations and the underlying evidence. Most recommendations are well reasoned. For some, the evidence is unclear and recommendations require some qualification. While the KDIGO guideline stresses the potential risks of intravenous iron therapy, withholding iron might have its own risks. The recommendation to avoid hemoglobin levels falling below 9 g/dL sets a lower bound of "acceptability" that may increase blood transfusion. Given the lack of research supporting the optimal transfusion strategy for end-stage renal disease patients, it is difficult to weigh the risks and benefits of red blood cell transfusion. We find a paucity of evidence that hemoglobin concentration targeted between 11 and 11.5 g/dL is associated with a safety risk. Although the evidence that erythropoiesis-stimulating agent use improves patient quality of life is poor, it is possible that the instruments used to measure quality of life may not be well attuned to the needs of chronic kidney disease or dialysis patients. Our last section focuses specifically on the recommendations to treat anemia in children.