[Cuff Shaving in Recurrent Exit-Site Infections in a Patient on Peritoneal Dialysis].

In patients on peritoneal dialysis, the cutaneous emergency (exit-site) represents a potential access route to the peritoneum; consequently, it can become a site for microbial infections. These infections, initially localized to the exit-site, may spread to the peritoneum causing peritonitis, which is the most common cause of drop-out from peritoneal dialysis and transition to hemodialysis. Peritoneal catheters have dacron caps which have the function of counteracting the traction of the catheter itself and at the same time acting as a barrier for microorganisms, preventing the spread towards the peritoneum. Despite this, the same dacron cap can represent a sort of nest for microorganisms to colonize and, with the formation of a biofilm that facilitates their proliferation, make the same organisms impervious to antibiotic therapy and even resistance to them. The most effective tool for monitoring the health status of the exit-site is represented by the objective examination. This examination, through the use of well-defined scales, helps to provide a pathological score of the exit, facilitating the implementation of necessary precautions. In the presence of recurrent exit-site infections, from both Gram positive and Gram negative bacteria, minimally invasive surgical therapy is a valid approach to break this vicious circle. It helps avoid subjecting the patient to the removal of the peritoneal catheter, temporary transition to hemodialysis with the insertion of a central venous catheter, and subsequent repositioning of another peritoneal catheter. We propose the case of a recurrent Staphylococcus Aureus infection resolved after cuff shaving of the exit-site.

[Peritoneal Dialysis Network in North-East Italy: Survey About the Peritoneal Catheter Exit-Site Infection Management and Comparison with ISPD Guidelines].

Introduction. The Triveneto Peritoneal Dialysis (PD) Network aims to bring together doctors and nurses who deal with PD in a collaborative network in which to exchange mutual knowledge and optimize the use of this method of replacing renal function. A topic of particular interest was the management of peritoneal catheter exit-site infection, given the recent publication of the new guidelines of the International Society of Peritoneal Dialysis (ISPD). Materials and methods. The survey concerned the criteria for carrying out nasal swab and exit-site, management of exuberant granulation tissue "Proud Flesh", treatment of exit-site infection (ESI), use of silver dressings, the role of subcutaneous tunnel ultrasound and cuff shaving. Results. All PD centers in the North-East Italy area have joined the survey with at least one operator per centre. There was a wide variability between the indications for performing the exit-site swab. In the presence of ESI, the prevalent approach is that of oral systemic empiric therapy associated (20.0%) or less (28.9%) with topical therapy, and then adapting it in a targeted manner to the culture examination. Discussion. From the discussion of the survey emerged the importance of the ESI as an outcome indicator, which allows us to verify whether our clinical practice is in line with the reference standards. It is essential to know and base our activity on what is indicated in national and international guidelines and to document the events that occur in the patient population of each dialysis unit.

[Omentopexy in Peritoneal Catheter Malfunction].

Among the various problems associated with peritoneal dialysis, besides infectious causes, the risk of catheter malfunction plays a significant role in conditioning the continuation of the method, accounting for up to 15-18% of the total causes of dialysis drop-out. When non-invasive maneuvers, such as the use of laxatives to stimulate intestinal peristalsis or heparin and/or urokinase have no effect, videolaparoscopy is the only method that directly detects the precise causes of peritoneal catheter malfunction. Those found are, with decreasing frequency, the winding of the catheter between the intestinal loops and the omentum (wrapping), the dislocation of the catheter, the combination of wrapping and dislocation, the occlusion of the catheter by a fibrin plug, the adhesions between the intestine and abdominal wall, the occlusion of the catheter by epiploic appendages or adnexal tissue and, occasionally, the presence of a new formation of endoperitoneal tissue enveloping and obstructing the peritoneal catheter. We report the case of a young patient of African ethnicity who, only five days after catheter placement, experienced malfunction. A videolaparoscopy revealed wrapping with invagination of omental tissue inside the catheter. After omental debridement, a proper peritoneal cavity washout with heparin was resumed, and after a couple of weeks, APD was initiated. About a month later, a new malfunction without signs of coprostasis or problems with the abdominal radiogram was observed. However, a subsequent catheterography confirmed the blockage of drainage. This was followed by another catheterography and omentopexy, with definitive solution of the Tenckhoff malfunction.

[A case of AL amyloidosis with fulminant evolution].

Amyloidosis represents a heterogeneous group of pathologies characterized by the deposit, in the form of fibrils, in the various organs and tissues of the body, of abnormal proteins; the deposits made up of these fibrils are called amyloid or amyloid substance. AL amyloidosis, also called "light chains", is a primary form characterized by deposits of light chains of monoclonal immunoglobulins, proteins that are produced by the bone marrow with the aim of protecting the body from pathological processes; for unknown reasons, these immunoglobulins, once fulfilled their function, do not dissolve but, on the contrary, they transform into amyloid fibrils and accumulate progressively, transported by the bloodstream, in the various organs and tissues. Below we report the case of a 77-year-old Caucasian male patient hospitalized at our Operative Unit for nephrotic syndrome and creatinine increase in the last couple of months, compared to previous normal tests. The patient underwent a renal biopsy and a bone marrow smear with evidence of AL amyloidosis (or primary amyloidosis) and of the presence, at serum immunofixation, of small IgG multiple myeloma k. Treated with bortezomib (1 mg/m 2 ) and soldesam (10 mg) first and with lenalidomid after, the patient had a clinical course burdened by symptomatic hypotension, due to severe dysautonomia. He had to start replacement treatment with haemodiafiltration for terminal kidney disease two months after the onset of illness. He died 4 months after the first hospitalization for nephrotic syndrome.

[Escherichia coli-induced emphysematous pyelonephritis in a diabetic patient with polycystic kidney disease]. / Pielonefrite enfisematosa da escherichia coli in una paziente diabetica con reni policistici.

Emphysematous pyelonephritis is a rare, necrotizing infection of the kidney and the perirenal space resulting in the formation of gas in both structures and associated with a high mortality rate. In 90% of cases it affects one kidney only; in the remaining 10% with bilateral emphysematous pyelonephritis aggressive surgical intervention may be required. Women are much more frequently affected than men, with diabetes mellitus (in 70-90% of cases) and urinary tract obstruction being common predisposing conditions. The pathogenesis of the disease is linked to four main factors: the presence of gasforming bacteria; hyperglycemia; inadequate tissue perfusion; and reduced immune response. Lactose-fermenting bacteria such as Escherichia coli and Klebsiella pneumoniae are the most common infectious agents. We report a case of unilateral emphysematous pyelonephritis due to a ruptured cyst infected by E. coli in a diabetic patient with polycystic kidney disease. The resulting septic shock necessitated an emergency right nephrectomy.

[Recurrent multifocal cancer lesions in a patient on hemodialysis after kidney pancreas transplant failure]. / Lesioni neoplastiche multifocali e recidivanti in un paziente in emodialisi dopo fallimento di trapianto combinato rene-pancreas.

Cancer is an important cause of mortality in patients on hemodialysis and kidney transplant recipients. Immunodepression and the genotoxic action of uremia are critical pathogenic agents. A 59-year-old man, ex-smoker, who had been on hemodialysis for seven months because of uremic degeneration of diabetic nephropathy, underwent a combined kidney-pancreas transplant in 1991, complicated by slow-resolution CMV infection. In 1993, after kidney graft failure due to chronic rejection, hemodialysis treatment was restarted with good pancreatic function. Steroid therapy was interrupted and azathioprine and cyclosporine immunosuppressive therapy maintained. In September 2007 the patient was diagnosed with two neoplasms of the oral mucosa: a well-differentiated squamous carcinoma and a spinocellular carcinoma associated with field cancerization. The tumors were resected, followed by laser treatment. Histological examination revealed squamous cell carcinoma without lymph node involvement. Azathioprine was interrupted. In January 2008 adjuvant radiotherapy to the surgical areas of the oral mucosa and neck was started. In February a verrucous nevus on the patient's chest turned out to be a spinocellular carcinoma in situ. In May 2008 recurrence of keratinizing squamous carcinoma of the oral mucosa was found, this time with nodal involvement. Cyclosporine administration was interrupted and after consultation with the oncology committee it was decided to continue with supportive therapy only, until the patient's death in August 2008.

Aquaporin-2 (AQP2) urinary excretion and assumption of water with different mineral content in healthy subjects.

The aquaporin-2 (AQP2) plays a key role in AVP-induced absorption of water, and its urinary excretion is related to its function. We aimed to test if the assumption of water with different mineral content can modify the expression of AQP2, leading to a change in AQP2 urinary concentration, in 20 healthy young subjects. Each subject received an oral water load (LM or HM) of 250 mL/hour for four hours, and several variables were measured. Plasmatic osmolality after water assumption was significantly reduced with no differences after the low (LM) or the high mineral (HM) water load. Urinary osmolality and plasmatic vasopressin concentration were significantly reduced after an assumption of both kinds of water. However, serum vasopressin was lower after HM water assumption than after LM. AQP2 urinary excretion was significantly reduced after water assumption with respect to the basal level and it was lower after LM than after HM water assumption. The different mineral content of water was investigated as a factor contributing to the development of hypertension. Considering that AQP2 can play a role in pathogenesis of hypertension, our demonstration that AVP-mediated AQP2 urinary excretion is strictly influenced by the consumption of water with different mineral content suggests a new, interesting field of investigation related to the link between blood pressure alterations and nutritional habits.

Circadian rhythm of hydration in healthy subjects and uremic patients studied by bioelectrical impedance analysis.

BACKGROUND: Healthy subjects and patients after successful kidney transplantation show a circadian rhythm for glomerular filtration rate and for the glomerular transport of macromolecules. We aimed to evaluate by bioelectrical impedance analysis (BIA) whether body hydration status also follows a circadian rhythm in patients with impaired renal function. METHODS: The study was conducted on 28 subjects divided into 3 groups: 8 healthy volunteers, 8 patients affected by chronic kidney disease and 12 end-stage renal disease (ESRD) patients on hemodialysis. During 24 h, 9 BIA measurements were taken in every subject every 180 min. RESULTS: BIA findings demonstrate that normal subjects have a circadian rhythm in hydration status that reaches maximum body water content at night, between 21.00 and 23.00 h. In patients with chronic kidney disease, this rhythm, with maximum at night, is maintained. The rhythm is also present in ESRD patients, if the residual diuresis is at least 500 ml/day, while there is no rhythm when residual diuresis is <300 ml/day. CONCLUSIONS: In normal subjects, body hydration status shows a circadian rhythm, which is weakened or lost in oligoanuric patients on dialysis, but partially maintained in subjects with preterminal uremia and in hemodialyzed patients with residual diuresis >500 ml/day.

Statins in nephrotic syndrome: a new weapon against tissue injury.

The nephrotic syndrome is characterized by metabolic disorders leading to an increase in circulating lipoproteins levels. Hypertriglyceridemia and hypercholesterolemia in this case may depend on a reduction in triglyceride-rich lipoproteins catabolism and on an increase in hepatic synthesis of Apo B-containing lipoproteins. These alterations are the starting point of a self-maintaining mechanism, which can accelerate the progression of chronic renal failure. Indeed, hyperlipidemia can affect renal function, increase proteinuria and speed glomerulosclerosis, thus determining a higher risk of progression to dialysis. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in cholesterol synthesis from mevalonate and its inhibitors, or statins, can therefore interfere with the above-mentioned consequences of hyperlipidemia. Statins are already well known for their effectiveness on primary cardiovascular prevention, which cannot be explained only through their hypolipemic effect. As far as kidney diseases are concerned, statin therapy has been shown to prevent creatinine clearance decline and to slow renal function loss, particularly in case of proteinuria, and its favorable effect may depend only partially on the attenuation of hyperlipidemia. Statins may therefore confer tissue protection through lipid-independent mechanisms, which can be triggered by other mediators, such as angiotensin receptor blockers. Possible pathways for the protective action of statins, other than any hypocholesterolemic effect, are: cellular apoptosis/proliferation balance, inflammatory cytokines production, and signal transduction regulation. Statins also play a role in the regulation of the inflammatory and immune response, coagulation process, bone turnover, neovascularization, vascular tone, and arterial pressure. In this study, we would like to provide scientific evidences for the pleiotropic effects of statins, which could be the starting point for the development of new therapeutical strategies in different clinical areas.

Kidney aging: from phenotype to genetics.

Aging is a physiological process that causes structural and functional changes in human body systems, sometimes leading to various organ failure. As far as the kidney is concerned, both genetic factors and environmental agents may influence the tissues damage in elderly people and the related loss of function. On the other hand, functional adaptations to structural changes appear to be compromised by co-morbid conditions that are frequently found in elderly people, such as atherosclerosis and hypertension. It is not yet known whether physiological aging is inevitably accompanied by a decline in renal function or how rapidly it might happen. The discovery of molecular mechanisms responsible for tissue damage in aging could offer new perspectives on interventions. The role of nitric oxide, oxidative stress, the renin-angiotensin system, changes in length of telomeres, and klotho gene expression are important subjects for further in-depth studies about aging. A better understanding of physiological renal aging could improve the clinical approach to this process and widen the therapeutic possibilities offered by transplantation.

The effect of two different protocols of potassium haemodiafiltration on QT dispersion.

BACKGROUND: The risk of developing cardiovascular diseases is higher in patients on haemodialysis than in the general population. These patients may develop arrhythmias that depend on the extra- and intracellular concentrations of potassium. ECG findings, particularly the QT interval and its dispersion (QT(d)) and the QT(c) (QT interval corrected for heart rate according to Bazett's formula) and its dispersion (QT(cd)), may be direct indicators of the risk of developing arrhythmia. METHODS: Our cohort comprised 28 patients who were dialysed for 3.5-4 h three times per week, first with haemodiafiltration with a constant potassium concentration (HDF) in the dialysis bath then with haemodiafiltration with variable concentrations of potassium (HDF(k)). ECGs were done at different time intervals: at the start of dialysis (T(0)), at 15 (T(15)), 45 (T(45)), 90 (T(90)) and 120 min (T(120)) after the beginning of the session, and at the end of treatment (T(end)). ECG-derived data (QT, QT(d), QT(c) and QT(cd)) were measured. At the same time points, plasma electrolytes, intra-erythrocytic potassium and the electrical membrane potential at rest (REMP) of the erythrocytic membrane were measured. RESULTS: Plasma potassium concentration diminished more gradually in HDF(k) than in HDF, the difference being statistically significant at T(15) and T(45) (P<0.05), and T(90) (P<0.01). The intra-erythrocytic potassium concentration remained constant throughout the observation period. In both HDF and HDF(k), REMP was lower at all points after T(0) (P<0.05), but the reduction was greater and more significant in HDF than in HDF(k) at T(15) and T(120) (P<0.05). ECG revealed a statistically significant diminution in HDF(k) vs HDF in the measures of dispersion of QT and QT(c) at T(15), T(90), T(120) and T(end) (P<0.01) and of QT(cd) at T(45) (P<0.05). The mean of QT(d), adjusted for plasma potassium, increased over time in HDF with large alternate mean increase and decrease peaks and error intervals. In HDF(k), instead, there was a progressive and constant diminution with minor error intervals. QT(cd) adjusted for plasma potassium had the same trend. A marked difference was found between the final values in standard HDF and those in HDF(k). CONCLUSIONS: HDF and HDF(k) have significantly different effects on QT(c). ECG data demonstrate that the risk of arrhythmia could be lower, with a variable removal of potassium during haemodialysis. With HDF but not HDF(k), hyperpolarization of the cell membrane is detected, and this could have a destabilizing effect on different types of cardiac cell, giving rise to retrograde circuits.