Dent–Wrong disease and other rare causes of the Fanconi syndrome

Dent–Wrong disease, an X-linked recessive disorder of the proximal tubules, presents with hypercalciuria, nephrocalcinosis, nephrolithiasis, renal insufficiency, low-molecular-weight proteinuria, rickets and/or osteomalacia. Dent and Friedman initially characterized the disorder in 1964 following studies of two patients with rickets who presented with hypercalciuria, hyperphosphaturia, proteinuria and aminoaciduria. Since then, extensive investigation identified two genetic mutations (CLCN5 and OCRL1) to be associated with Dent–Wrong disease. Clinical features supported by laboratory findings consistent with proximal tubule dysfunction help diagnose Dent–Wrong disease. Genetic analysis supports the diagnosis; however, these two genes can be normal in a small subset of patients. The differential diagnosis includes other forms of the Fanconi syndrome, which can be hereditary or acquired (e.g. those related to exposure to exogenous substances). Treatment is supportive with special attention to the prevention of nephrolithiasis and treatment of hypercalciuria. We review the rare forms of Fanconi syndrome with special attention to Dent–Wrong disease

Effect of dialysate temperature on central hemodynamics and urea kinetics

Effect of dialysate temperature on central hemodynamics and urea kinetics. Use of cool dialysate is associated with increased intradialytic blood pressure, but the hemodynamic mechanism is unknown. Whether changes in dialysate temperature affect muscle blood flow, which may the alter the degree of urea compartmentalization, also is unknown. We measured hemodynamics and blood and dialysate-side urea kinetic indices in nine hemodialysis patients during two cool (35.0°C) versus two warm (37.5°C) dialysate treatments. The % change in mean arterial pressure was different when using the cool (+6.5 ± 9.7 mm Hg) versus the warm (-13.4 ± 3.6) dialysate (P < 0.01), despite comparable amounts of fluid removal. Percent changes in cardiac output were similar with the two dialysates, and thus the blood pressure effect was due primarily to changes in total peripheral resistance (%ΔTPR, cool +26 ± 13.6, warm +8.6 ± 14.5; P < 0.02). During cool dialysate use tympanic membrane temperature changed by -0.51 ± 0.23°C, whereas body temperature increased by 0.52 ± 0.14°C during use of warm dialysate. Measured urea recovery normalized to the predialysis urea nitrogen concentration was similar with the two treatments: cool 31.3 ± 0.039 liter-1; warm 29.7 ± 0.021; P = NS. In a second study, post-dialysis urea rebound values from 15 seconds to 30 minutes, expressed as the percent of the post-dialysis SUN, were similar after the two treatments: cool 11.79 ± 1.4; warm 12.21 ± 2.27, P = NS. The results suggest that increased blood pressure associated with use of cool dialysate is due to an increased TPR, and that this alteration in hemodynamics has no clinically important effects on either the amount of urea removal or the extent of post-dialysis urea rebound

Thoughts and Progress

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75183/1/j.1525-1594.1999.06248.x.pd

Principles of Quantitative Fluid and Cation Replacement in Extreme Hyperglycemia

Hyperglycemia may cause profound deficits of water, sodium and potassium through osmotic diuresis, which continues during treatment as long as there is glucosuria. Replacement fluids should cover both the deficits at presentation and the ongoing losses during treatment. At presentation with hyperglycemia, quantitative estimates of the deficits in water, sodium and potassium are based on rapid body weight changes, which indicate changes in body water, and on the serum sodium concentration corrected to a normal serum glucose level. The corrected serum sodium concentration provides a measure of the water deficit relative to the cation deficit (sodium, plus potassium) that is useful in guiding the choice of monovalent cation concentration in the initial replacement fluids. Monitoring clinical status, serum chemistries (glucose, sodium, potassium, total carbon dioxide), urine flow rate, and urine chemistries (sodium and potassium) during the course of fluid and cation replacement therapy is critical. This monitoring guides the volume and composition of replacement solutions for deficits developing during treatment and the management of potassium balance and acid-base abnormalities, including metabolic acidosis, respiratory acidosis, rarely, and others

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Hemodialysis vascular access construction in the upper extremity: A review

© 2014 Wichtig Publishing. Purpose: This article reviews the conventional vascular access types in the upper extremities for hemodialysis. Methods: We performed a literature search for autogenous arteriovenous fistula in the upper extremities. Results: The upper extremities have four potential sites: radio-cephalic or radio-basilic transposition in the forearm, and brachio-cephalic or brachio-basilic transposition in the upper arm. A preoperative Duplex ultrasound provides valuable information regarding arterial inflow and venous outflow. The surgical approach to fistula formation and final product depends on vein diameter and length as well as proximal vein patency. The discussion focuses on access outcomes and management of common complications. Conclusions: The upper extremity arteriovenous fistula is the preferred access for hemodialysis. A number of arteriovenous fistulas can be created in the upper extremities. The Duplex ultrasound identifies suitable arteries and veins for successful arteriovenous hemodialysis fistula creation. Arteriovenous hemodialysis fistula has the best long-term patency outcomes and the lowest associated morbidity and mortality. Early detection and intervention can save the fistula when complications occur

Unusual sites for hemodialysis vascular access construction and catheter placement: A review.

© 2015 Wichtig Publishing. As more end-stage renal disease patients require hemodialysis and live longer, many will fail to develop or maintain a functioning upper extremity vascular access. When a patient exhausts vascular access sites in the upper extremities, new fistulas and grafts can be constructed in the lower extremities, thorax, and abdomen as long as a pair of proximate artery and vein provide adequate blood inflow and outflow, respectively. When only a moderate size vein with adequate blood flow provides a conduit to either a patent superior or inferior vena cava, inserting a double-lumen venous hemodialysis catheter can provide temporary or permanent access. We review the literature and report the unusual sites for hemodialysis vascular access and catheter placement

Gastrointestinal complications of acute kidney injury

Gastrointestinal (GI) complications are commonly encountered in patients with acute kidney injury (AKI) and are the result of uremia. Since the degree of uremia varies in AKI, a spectrum of symptoms and GI complications may occur. GI complications of AKI include anorexia, hiccups, upper and lower GI hemorrhage, as well as diseases of the small and large intestines. © Springer-Verlag Berlin Heidelberg 2010