Daniel Landry

Emergence of gentamicin-resistant bacteremia in hemodialysis patients receiving gentamicin lock catheter prophylaxis.

BACKGROUND AND OBJECTIVES Antibiotic locks in catheter-dependent chronic hemodialysis patients reduce the rate of catheter-related blood stream infections (CRIs), but there are no data regarding the long-term consequences of this practice. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Over a 4-year period, from October 1, 2002, to September 30, 2006, we initiated a gentamicin and heparin lock (GHL) protocol in 1410 chronic hemodialysis patients receiving dialysis through a tunneled catheter in eight outpatient units. RESULTS Within the first year of the GHL protocol, our CRI rate decreased from 17 to 0.83 events per 1000 catheter-days. Beginning 6 months after initiation of the GHL protocol, febrile episodes occurred in 13 patients with coagulase-negative Staphylococcus bacteremia resistant to gentamicin. Over the 4 years of GHL use, an additional 10 patients developed 11 episodes of gentamicin-resistant CRI (including 7 with Enterococcus faecalis), in which there were 4 deaths, 2 cases of septic shock requiring intensive care unit admission, and 4 cases of endocarditis. Because of these events, the GHL protocol was discontinued at the end of 2006. CONCLUSIONS Although the use of GHL effectively lowered the CRI rate in our dialysis population, gentamicin-resistant CRIs emerged within 6 months. Gentamicin-resistant infections are a serious complication of the long-term use of GHLs. Alternative nonantibiotic catheter locks may be preferable to decrease the incidence of CRIs without inducing resistant pathogens.

Reducing Catheter-Related Infections in Hemodialysis Patients

Not all hemodialysis accesses are created equal: Compared with patients with ESRD who have an arteriovenous fistula, those with a tunneled central venous catheter have a 15-fold increased risk of catheter-related bloodstream infection (CRBSI) and an all-cause mortality rate ranging from 12% to 25

Effects of Prolonged Ethanol Lock Exposure to Carbothane- and Silicone-based Hemodialysis Catheters: A 26-week Study:

Purpose Antibiotic locks in catheter-dependent chronic hemodialysis patients reduce the rate of catheter-related bloodstream infections (CRBSIs), but may be associated with the development of resistant bacteria. Ethanol-based catheter locks may provide a better alternative; however, there are limited data on the long-term integrity of dialysis catheters exposed to ethanol. Methods We performed in vitro testing of two types of hemodialysis catheters—silicone (SLC) and carbothane (CBT) based—with a 70% ethanol lock (EL) versus heparin lock (HL) for 26 weeks. Lock solutions were changed thrice weekly to mimic a conventional hemodialysis schedule. We tested mechanical properties of the catheters at 0, 13 and 26 weeks by examining stress/strain relationships (SS400%) and modulus of elasticity (ME). Electron microscopy was performed to examine catheter ultrastructure at 0 and 26 weeks. Results Catheter integrity for HL versus EL in SLC (SS400%: 4.5 vs. 4.5 MPa, p = NS; ME: 4.6 vs. 4.7 MPa, p = NS) or CBT-based catheters (SS400%: 7.6 vs. 8.9 MPa, p = NS; ME: 9.6 vs. 12.2 MPa, p = NS) were all similar at 13 and 26 weeks. Scanning electron microscopy revealed no structural changes in the central and luminal wall internal surfaces of EL- versus HL-treated catheters. Conclusions There were no significant differences in catheter integrity between SLC or CBT catheters exposed to a 70% EL for 26 weeks. Given its low cost, potential to avoid antibiotic resistance and structural integrity after 6 months of high-dose ethanol, ELs should be studied prospectively against antibiotic locks to assess the efficacy and safety in hemodialysis patients.

Parainfluenza virus infection associated with posterior reversible encephalopathy syndrome: a case report

IntroductionPosterior reversible encephalopathy syndrome is a clinical and radiological entity. The most accepted theory of posterior reversible encephalopathy syndrome is a loss of autoregulation in cerebral blood flow with a subsequent increase in vascular permeability and leakage of blood plasma and erythrocytes, producing vasogenic edema. In infection-associated posterior reversible encephalopathy syndrome, a clinical pattern consistent with systemic inflammatory response syndrome develops. Parainfluenza virus has not been reported in the medical literature to be associated with posterior reversible encephalopathy syndrome.Case presentationWe report herein the case of a 54-year-old Caucasian woman with posterior reversible encephalopathy syndrome associated with parainfluenza virus infection who presented with generalized headache, blurring of vision, new-onset seizure and flu-like symptoms.ConclusionInfection-associated posterior reversible encephalopathy syndrome as well as hypertension-associated posterior reversible encephalopathy syndrome favor the contribution of endothelial dysfunction to the pathophysiology of this clinicoradiological syndrome. In view of the reversible nature of this clinical entity, it is important that all physicians are well aware of posterior reversible encephalopathy syndrome in patients presenting with headache and seizure activity. A detailed clinical assessment leading to the recognition of precipitant factors in posterior reversible encephalopathy syndrome is paramount.

Hypercalcemia in Lung Cancer due to Simultaneously Elevated PTHrP and Ectopic Calcitriol Production: First Case Report

Calcitriol-mediated hypercalcemia has been reported in malignant lymphomas and granulomatous diseases but not in lung carcinoma. We describe a patient with squamous cell lung carcinoma with hypercalcemia and elevated calcitriol levels. A 60-year-old Caucasian male patient with stage IIIB squamous cell lung cancer developed hypercalcemia at 14.8 mg/dL two years after receiving chemotherapy and radiotherapy where labs showed a serum intact PTH: 7 pg/mL, PTHrP: 30 pmol/L, 1,25-hydroxyvitamin D (calcitriol): 76 pg/mL, and 25-hydroxyvitamin D levels: <4 ng/mL. Calcitriol levels were elevated despite undetectable 25-hydroxyvitamin D levels. There are no reported lung cancer cases with elevated calcitriol as an etiology of hypercalcemia. We believe that the elevated calcitriol levels in this case were due to a PTHrP-independent mechanism, possibly from either ectopic production of calcitriol in tumor cells or from increased activity of 1-alpha hydroxylase in the same cells. The patient died before the effects of prednisone therapy could be assessed. Studies are needed to investigate the cellular source of calcitriol and its role in hypercalcemia in patients with lung cancer.

Oxcarbazepine Therapy for Complete Central Diabetes Insipidus

Oxcarbazepine and carbamazepine cause hyponatremia by unknown mechanisms. We describe a patient with complete central diabetes insipidus and seizures who developed worsening hyponatremia when her dose of oxcarbazepine was increased. The patient maintained a normal serum sodium level and has had appropriately concentrated urine for 5 years on just oxcarbazepine, despite undetectable antidiuretic hormone (ADH) levels. This suggests that oxcarbazepine (or one of its metabolites) may stimulate collecting tubule V2 receptor-G protein complex independent of ADH, resulting in increased renal tubular water reabsorption. Oxcarbazepine may be useful as an alternative therapy for patients with central diabetes insipidus.