Faculty Bibliography

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.

BACKGROUND AND OBJECTIVES: Higher urinary uric acid excretion is a suspected risk factor for calcium oxalate stone formation. Febuxostat, a xanthine oxidoreductase inhibitor, is effective in lowering serum urate concentration and urinary uric acid excretion in healthy volunteers and people with gout. This work studied whether febuxostat, compared with allopurinol and placebo, would reduce 24-hour urinary uric acid excretion and prevent stone growth or new stone formation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this 6-month, double-blind, multicenter, randomized controlled trial, hyperuricosuric participants with a recent history of calcium stones and one or more radio-opaque calcium stone >/=3 mm (as seen by multidetector computed tomography) received daily febuxostat at 80 mg, allopurinol at 300 mg, or placebo. The primary end point was percent change from baseline to month 6 in 24-hour urinary uric acid. Secondary end points included percent change from baseline to month 6 in size of index stone and change from baseline in the mean number of stones and 24-hour creatinine clearance. RESULTS: Of 99 enrolled participants, 86 participants completed the study. Febuxostat led to significantly greater reduction in 24-hour urinary uric acid (-58.6%) than either allopurinol (-36.4%; P=0.003) or placebo (-12.7%; P<0.001). Percent change from baseline in the size of the largest calcium stone was not different with febuxostat compared with allopurinol or placebo. There was no change in stone size, stone number, or renal function. No new safety concerns were noted for either drug. CONCLUSIONS: Febuxostat (80 mg) lowered 24-hour urinary uric acid significantly more than allopurinol (300 mg) in stone formers with higher urinary uric acid excretion after 6 months of treatment. There was no change in stone size or number over the 6-month period.

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.

The recent trend to early initiation of dialysis (at eGFR >10 ml/min/1.73 m(2) ) appears to have been based on conventional wisdoms that are not supported by evidence. Observational studies using administrative databases report worse comorbidity-adjusted dialysis survival with early dialysis initiation. Although some have concluded that the IDEAL randomized controlled trial of dialysis start provided evidence that patients become symptomatic with late dialysis start, there is no definitive support for this view. The potential harms of early start of dialysis, including the loss of residual renal function (RRF), have been well documented. The rate of RRF loss (renal function trajectory) is an important consideration for the timing of the dialysis initiation decision. Patients with low glomerular filtration rate (GFR) may have sufficient RRF to be maintained off dialysis for years. Delay of dialysis start until a working arterio-venous access is in place seems prudent in light of the lack of harm and possible benefit of late dialysis initiation. Prescribing frequent hemodialysis is not recommended when dialysis is initiated early. The benefits of early initiation of chronic dialysis after episodes of congestive heart failure or acute kidney injury require further study. There are no data to show that early start benefits diabetics or other patient groups. Preemptive start of dialysis in noncompliant patients may be necessary to avoid complications. The decision to initiate dialysis requires informed patient consent and a joint decision by the patient and dialysis provider. Possible talking points for obtaining informed consent are provided.

There is emerging evidence that mild chronic hyponatremia (MCH), highly prevalent in the elderly and once considered asymptomatic, is a major independent risk factor for falls, fall-related fractures (independent of osteoporosis, age, and sex), impaired attention and gait, reductions in bone mineral density (BMD), and even death. Although research on MCH and bone health is emerging and ongoing, it has not been recognized in orthopedics. Orthopedic surgeons must be educated regarding the impact of hyponatremia on bone, as osteoporotic fractures have enormous socioeconomic consequences, and the problem will worsen. Orthopedic surgeons should also be included in research, in education, and in the establishment of diagnostic and treatment protocols. In this article, we review the current concepts of MCH and its impacts on the skeletal system.

Adenine phosphoribosyltransferase (APRT) deficiency, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC), and primary hyperoxaluria (PH) are rare but important causes of severe kidney stone disease and/or chronic kidney disease in children. Recurrent kidney stone disease and nephrocalcinosis, particularly in pre-pubertal children, should alert the physician to the possibility of an inborn error of metabolism as the underlying cause. Unfortunately, the lack of recognition and knowledge of the five disorders has frequently resulted in an unacceptable delay in diagnosis and treatment, sometimes with grave consequences. A high index of suspicion coupled with early diagnosis may reduce or even prevent the serious long-term complications of these diseases. In this paper, we review the epidemiology, clinical features, diagnosis, treatment, and outcome of patients with APRT deficiency, cystinuria, Dent disease, FHHNC, and PH, with an emphasis on childhood manifestations.