Oxalate nephropathy and intravenous vitamin C.

Oxalate nephropathy is a rare condition characterized by extensive calcium oxalate deposition in the renal tubules, resulting in kidney injury. There are primary forms of the disease that arise from genetic mutation causing overproduction of oxalate. More commonly, this condition is seen as a secondary phenomenon. The clinical presentation is nonspecific, with acute kidney injury and normal serologic study results. The characteristic finding on kidney biopsy is the presence of acute tubular injury associated with polarizable crystals in the tubular lumen and epithelial cytoplasm. We present a case of acute oxalate nephropathy in a patient with underlying systemic lupus erythematosus who recently received intravenous vitamin C.

Conversion of tunneled hemodialysis catheter into HeRO device can provide immediate access for hemodialysis.

Patients with central venous occlusion who are ''tunneled catheter dependent'' are a challenge for hemodialysis access. A relatively new option for them is the hemodialysis reliable outflow (HeRO) device that can be totally implanted subcutaneously. However, patients still require a tunneled hemodialysis catheter that is used until the HeRO device is mature, 4 to 6 weeks later. Here, we describe a conversion of an existing tunneled hemodialysis catheter into a HeRO device, which was combined with a ''self-sealing'' Flixene graft. This allowed almost immediate use of the HeRO device without the need for placement of a catheter.

Percutaneous endovascular management of occluded HeRO dialysis access device.

The Hemodialysis Reliable Outflow (HeRO) device is a novel alternative for dialysis access in patients with no suitable veins in the upper extremities. We placed a HeRO device in a 67-year-old woman with end-stage renal disease and 2 months later, it was being used for hemodialysis. After 1 month of uneventful use, the device thrombosed and it was rescued with a percutaneous endovascular approach. The device remains patent 6 months after the intervention.

Noninvasive interrogation of microvasculature for signs of endothelial dysfunction in patients with chronic renal failure.

Endothelial cell dysfunction (ECD) has been demonstrated in patients with end-stage renal disease (ESRD) who have cardiovascular disease (CD) or diabetes mellitus (DM). While techniques to examine conduit arteries have been adapted to these patients, evaluation of microvascular function has lagged behind. Therefore, we used laser Doppler flowmetry (LDF) and scanned laser Doppler imaging (LDI) to quantify parameters of the postocclusion reactive hyperemia and thermal hyperemic responses (local heating to 43 degrees C) in ESRD patients (n=63) and healthy individuals (n=33). Patients with ESRD were partitioned among those with either CD or DM or both (designated CDorDM, n=30), patients with both CD and DM (designated CD+DM, n=12, statistically similar to CDorDM), and patients with neither CD or DM (designated approximately CDor DM, n=33). LDF during thermal hyperemia showed a decrease in the thermal peaks and plateau as well as a delay in plateau compared with control, consistent with ECD. LDF during reactive hyperemia showed a decrease in the pay-back area under the curve, also consistent with ECD. approximately CDorDM were heterogeneous: almost 50% contained flow abnormalities similar to CDorDM. There was also a reduction in the number of functional arterioles on LDI images. Fourier analysis of LDF oscillations showed that low-frequency oscillations characterizing endothelial function were impaired in CDorDM and in many approximately CDorDM. The data demonstrate that ESRD patients with expected ECD (CDorDM) are characterized by distinct abnormalities in LDF parameters. However, similar abnormalities are found in approximately one-half of ESRD patients without evidence for CD or DM. Postocclusive and thermal interrogation of the microvasculature with laser Doppler-resolved parameters of the microcirculation, followed by Fourier analysis of the very slow oscillations, may provide a valuable adjunct to early noninvasive diagnosis of ECD in ESRD, especially important in a subpopulation of ESRD patients with no known CD or DM, which could be at increased risk of impending clinical manifestations of vasculopathy.