[Nephrologists' role in a changing climate].

Human-induced climate changes represent an increasing concern in recent years. Among the medical specialties, Nephrology is the most interested in the negative effects of climate changes on human health. Kidneys in fact play a crucial role in blood volume regulation as well as in the extra- and intracellular osmolality that allow normal metabolism. Furthermore, urinary concentration minimizes fluid losses, while also insuring the excretion of nitrogenous wastes. The harmful effects of heat can lead to both acute and chronic kidney diseases, electrolyte abnormalities, kidney stone formation and urinary tract infections. As global warming increases, major efforts are required worldwide to assure adequate hydration and prevent overheating in vulnerable populations. While our activities make us responsible agents, there are also several opportunities to change the game, both individually and as a scientific society. This call to action intends to raise awareness on environmentally sustainable practices and encourage the nephrology community in Italy to participate in this important discussion.

[Membranoproliferative glomerulonephritis with relapsing episodes of acute kidney injury in the Schnitzler syndrome].

The Schnitzler syndrome (SS) is a rare and underdiagnosed entity that associates a chronic urticarial rash, monoclonal IgM (or sometimes IgG) gammopathy and signs and symptoms of systemic inflammation. During the past 45 years the SS has evolved from an elusive, little-known disorder to the paradigm of a late-onset auto-inflammatory acquired syndrome. Though there is no definite proof of its precise pathogenesis, it should be considered as an acquired disease involving abnormal stimulation of the innate immune system, which can be reversed by the interleukin 1 (IL-1) receptor antagonist anakinra. Here we describe the case of a 56-year-old male Caucasian patient affected by SS and hospitalized several times in our unit because of relapsing episodes of acute kidney injury. He underwent an ultrasound-guided percutaneous kidney biopsy in September 2012, which showed the histologic picture of type I membranoproliferative glomerulonephritis. He has undergone conventional therapies, including nonsteroidal anti-inflammatory drugs, steroids and immunosuppressive drugs; more recently, the IL-1 receptor antagonist anakinra has been prescribed, with striking clinical improvement. Although the literature regarding kidney involvement in the SS is lacking, it can however be so severe, as in the case reported here, to lead us to recommend the systematic search of nephropathy markers in the SS.

Is the removal of a central venous catheter always necessary in the context of catheter-related right atrial thrombosis?

Catheter-related right atrial thrombosis is a severe and life-threatening complication of central venous catheters in both adult and young patients. Catheter-related right atrial thrombosis can occur with any type of central venous catheters, utilized either for hemodialysis or infusion. Up to 30% of patients with central venous catheter are estimated to be affected by catheter-related right atrial thrombosis; however, neither precise epidemiological data nor guidelines regarding medical or surgical treatment are available. This complication seems to be closely associated with positioning of the catheter tip in the atrium, whereas it is unlikely with a tip located within superior vena cava. Herein, we report the case of a patient affected by catheter-related right atrial thrombosis, who showed a quick resolution of thrombosis with a new therapeutic scheme combining loco-regional thrombolytic therapy (urokinase as a locking solution) and systemic anticoagulation therapy (vitamin K antagonists), thus avoiding catheter removal. Neither complications of the combination therapy were reported, nor recurrence of catheter-related right atrial thrombosis occurred. In conclusion, the combination therapy here described was safe, quick and effective, achieving the goal of not removing the catheter.

Lancisi's sign and central venous catheter tip position: a case report.

INTRODUCTION: Valvular disease and pulmonary hypertension are common conditions in haemodialysis patients. In presence of tricuspid regurgitation, an increased retrograde blood flow into the right atrium during ventricle systole results in a typical modification of the normal venous waveform, creating a giant c-v wave. This condition clinically appears as a venous palpable pulsation within the internal jugular vein, also known as Lancisi's sign. CASE REPORT: An 83-year-old woman underwent haemodialysis for 9 years. After arteriovenous fistula thrombosis, a right internal jugular vein non-tunnelled central venous catheter (CVC) was placed. About one month later, the patient was referred to our facility for the placement of a tunnelled CVC. Neck examination revealed an elevated jugular venous pulse, the Lancisi's sign. Surprisingly, chest x-ray posteroanterior view showed the non-tunnelled catheter tip in correspondence with the right ventricle. She underwent surgery for temporary to tunnelled CVC conversion using the same venous insertion site (Bellcath®10Fr-length 25 cm to Mahurkar®13.5Fr-length 19 cm). In the postoperative period, we observed a significant reduction of the jugular venous pulse. DISCUSSION: The inappropriate placement of a 25-cm temporary CVC in the right internal jugular vein worsened the tricuspid valve regurgitation, which became evident by the Lancisi's sign. Removal of the temporary CVC from the right ventricle resulted in improved right cardiac function. Safe approaches recommended by guidelines for the CVC insertion technique and for checking the tip position should be applied in order to avoid complications.

Kidney involvement in the Schnitzler syndrome, a rare disease.

The Schnitzler syndrome (SS) is a rare and underdiagnosed entity that associates a chronic urticarial rash, monoclonal IgM (or sometimes IgG) gammopathy and signs and symptoms of systemic inflammation. During the past 45 years, the SS has evolved from an elusive little-known disorder to the paradigm of a late-onset acquired auto-inflammatory syndrome. Though there is no definite proof of its precise pathogenesis, it should be considered as an acquired disease involving abnormal stimulation of the innate immune system, which can be reversed by the interleukin-1 receptor antagonist anakinra. It clearly expands our view of this group of rare genetic diseases and makes the concept of auto-inflammation relevant in polygenic acquired diseases as well. Increasing numbers of dermatologists, rheumatologists, allergologists, haematologists and, more recently, nephrologists, recognize the SS. The aim of this review is to focus on kidney involvement in the SS. Although the literature regarding kidney involvement in the SS is very poor it can be severe, as in our own case here reported, leading us to recommend the systematic search for nephropathy markers in the SS.

The impact of haemodialysis arteriovenous fistula on haemodynamic parameters of the cardiovascular system.

BACKGROUND: Satisfactory vascular access flow (Qa) of an arteriovenous fistula (AVF) is necessary for haemodialysis (HD) adequacy. The aim of the present study was to further our understanding of haemodynamic modifications of the cardiovascular system of HD patients associated with an AVF. The main objective was to calculate using real data in what way an AVF influences the load of the left ventricle (LLV). METHODS: All HD patients treated in our dialysis unit and bearing an AVF were enrolled into the present observational cross-sectional study. Fifty-six patients bore a lower arm AVF and 30 an upper arm AVF. Qa and cardiac output (CO) were measured by means of the ultrasound dilution Transonic Hemodialysis Monitor HD02. Mean arterial pressure (MAP) was calculated; total peripheral vascular resistance (TPVR) was calculated as MAP/CO; resistance of AVF (AR) and systemic vascular resistance (SVR) are connected in parallel and were respectively calculated as AR = MAP/Qa and SVR = MAP/(CO - Qa). LLV was calculated on the principle of a simple physical model: LLV (watt) = TPVR·CO(2). The latter was computationally divided into the part spent to run Qa through the AVF (LLVAVF) and that part ensuring the flow (CO - Qa) through the vascular system. The data from the 86 AVFs were analysed by categorizing them into lower and upper arm AVFs. RESULTS: Mean Qa, CO, MAP, TPVR, LLV and LLVAVF of the 86 AVFs were, respectively, 1.3 (0.6 SD) L/min, 6.3 (1.3) L/min, 92.7 (13.9) mmHg, 14.9 (3.9) mmHg·min/L, 1.3 (0.6) watt and 19.7 (3.1)% of LLV. A statistically significant increase of Qa, CO, LLV and LLVAVF and a statistically significant decrease of TPVR, AR and SVR of upper arm AVFs compared with lower arm AVFs was shown. A third-order polynomial regression model best fitted the relationship between Qa and LLV for the entire cohort (R (2) = 0.546; P < 0.0001) and for both lower (R (2) = 0.181; P < 0.01) and upper arm AVFs (R (2) = 0.663; P < 0.0001). LLVAVF calculated as % of LLV rose with increasing Qa according to a quadratic polynomial regression model, but only in lower arm AVFs. On the contrary, no statistically significant relationship was found between the two parameters in upper arm AVFs, even if mean LLVAVF was statistically significantly higher in upper arm AVFs (P < 0.0001). CONCLUSIONS: Our observational cross-sectional study describes statistically significant haemodynamic modifications of the CV system associated to an AVF. Moreover, a quadratic polynomial regression model best fits the relationship between LLVAVF and Qa, but only in lower arm AVFs.

[An unusual cause of ureteral obstruction in kidney transplant]. / Una causa non usuale di ostruzione ureterale nel trapianto renale.

Inguinal herniation of the ureter in a kidney transplantation is a rare cause of late distal ureteral obstruction. Herniation is usually secondary to the implant of a long redundant ureter and to its course on the spermatic cord. This clinical condition can worsen graft function in the presence of ipsilateral hydroureteronephrosis. In this review, we describe the case of an asymptomatic 51-year-old man with a history of right iliac renal allotransplantation 12 years before. Kidney ultrasound showed moderate hydroureteronephrosis and ureteral kneeling at the upper third of the inguinal canal. The patient presented a mild increase in serum creatinine; physical examination revealed an ipsilateral inguinal hernia. A CT scan of the abdomen with no contrast medium confirmed middle-distal ureteral kneeling engaging in the sac of the right inguinal hernia. The patient underwent surgical hernia repair with no complications and his renal function recovered completely.

High versus low dialysate sodium concentration in chronic haemodialysis patients: a systematic review of 23 studies.

BACKGROUND: It is the object of debate whether a low or high dialysate sodium concentration (DNa(+)) should be advocated in chronic haemodialysis patients. In this paper, we aimed at evaluating benefits and harms of different DNa(+) prescriptions through a systematic review of the available literature. METHODS: MEDLINE and CENTRAL databases were searched for studies comparing low or high DNa(+) prescriptions. Outcomes of interest were mortality, blood pressure (BP), interdialytic weight gain (IDWG), plasma sodium, hospitalizations, use of anti-hypertensive agents and intradialytic complications. RESULTS: Twenty-three studies (76 635 subjects) were reviewed. There was high heterogeneity in the number of patients analysed, overall study quality, duration of follow-up, DNa(+) and even in the definition of 'high' or 'low' DNa(+). The only three studies looking at mortality were observational. The risk of death was related to the plasma-DNa(+) gradient, but was also shown to be confounded by indication from the dialysate sodium prescription itself. BP was not markedly affected by high or low DNa(+). Patients treated with higher DNa(+) had overall higher IDWG when compared with those with lower DNa(+). Three studies reported a significant increase in intra-dialytic hypotensive episodes in patients receiving low DNa(+). Data on hospitalizations and use of anti-hypertensive agents were sparse and inconclusive. CONCLUSIONS: There is currently no definite evidence proving the superiority of a low or high uniform DNa(+) on hard or surrogate endpoints in maintenance haemodialysis patients. Future trials adequately powered to evaluate the impact of different DNa(+) on mortality or other patient-centred outcomes are needed.

[An unusual cause of acute pyelonephritis: the retrocaval ureter]. / Una causa non usuale di pielonefrite acuta: l'uretere retrocavale.

Retrocaval ureter is a rare congenital malformation in which the proximal right ureter courses toward the midline on the posterior aspect of the inferior vena cava before emerging medial and anterior to this structure and then descending into the pelvis. This anatomical anomaly may be asymptomatic or manifest clinically, usually starting from the fourth decade of life, with flank pain, pyelonephritis, gross hematuria or other rarer signs. We describe the case of a young woman being hospitalized because of acute pyelonephritis; she had previously complained of flank pain associated with episodes of high fever. Computed tomography of the abdomen identified the malformation. The patient underwent surgical correction by laparoscopy and, at one year of follow-up, did not show any further clinical problem.

Efficacy and Safety of a New Technique of Conversion from Temporary to Tunneled Central Venous Catheters.

The usually applied conversion technique from temporary to tunneled central venous catheters (CVCs) using the same venous insertion site requires a peel-away sheath. We propose a conversion technique without peel-away sheath: a guide wire is advanced through the existing temporary CVC; then, a subcutaneous tunnel is created from the exit to the venotomy site. After removing the temporary CVC, the tunneled one is advanced along the guide wire. The study group included all patients requiring a catheter conversion from January 2012 to June 2014; the control group included incident patients who had received de novo placement of tunneled CVCs from January 2010 to December 2011. The main outcome measures were technical success and immediate complications. Seventy-two tunneled catheters (40 with our conversion technique and 32 with the traditional one) were placed in 72 patients. The technical success was 95% in the study group and 75% in the controls (p = 0.019). The immediate complications were one bleeding in the study group (2.5%) and one air embolism, one pneumothorax, and four bleedings (18.7%) in the controls (p = 0.039). Conversion from temporary to tunneled CVC using a guide wire and without a peel-away sheath is an effective and safe procedure.

Probing the dry weight by bioimpedance: the resistance stabilization test.

Probing dry weight (DW) was largely dependent on clinical subjective estimate until recently. New bedside non-invasive tools have been developed with the aim of providing more objective information on volume status and guiding physicians in the quest for DW. Among them, bioimpedance appears to be very promising in the achievement of this goal. We have developed a test aimed to assess DW in complicated hemodialysis (HD) patients and named it "RE.sistance S.tabilization T.est" (RE.S.T.). It is based on the following four items: 1. one or more HD sessions lasting 6 h with ultrafiltration (UF) rate ≤0.5 kg/h are planned; 2. bioimpedance measurements are determined injecting 800 µA at 50 kHz alternating sinusoidal current with a standard tetrapolar technique. Resistance (R) is recorded at the start of the treatment (R0) and every 15 min (Rt) during HD until the end of the 6-h session; 3. DW is defined as that achieved at the time point at which three consecutive R0/Rt ratios show in-between changes ±1% despite ongoing UF; 4. if at the end of the 6-h HD session R stabilization is not attained, a new 6-h HD treatment with UF rate ≤0.5 kg/h is planned until a bioimpedance DW (according to the item 3) is obtained. As said, we are applying RE.S.T. to assess DW in complicated HD patients. Here we report a paradigmatic case which illustrates quite brilliantly its clinical usefulness. The patient was admitted to our nephrology ward with a hypertensive crisis, a very large drug regimen notwithstanding. His DW was reduced by 5 kg after four 6-h HD sessions probing his DW by means of RE.S.T. He was discharged with a normal blood pressure and no need for anti-hypertensive drugs. In conclusion, RE.S.T. appears to be a (the) brilliant solution in solving the old problem of DW in HD patients.

Ranking of factors determining potassium mass balance in bicarbonate haemodialysis.

BACKGROUND: One of the most important pathogenetic factors involved in the onset of intradialysis arrhytmias is the alteration in electrolyte concentration, particularly potassium (K(+)). METHODS: Two studies were performed: Study A was designed to investigate above all the isolated effect of the factor time t on intradialysis K(+) mass balance (K(+)MB): 11 stable prevalent Caucasian anuric patients underwent one standard (∼4 h) and one long-hour (∼8 h) bicarbonate haemodialysis (HD) session. The latter were pair-matched as far as the dialysate and blood volume processed (90 L) and volume of ultrafiltration are concerned. Study B was designed to identify and rank the other factors determining intradialysis K(+)MB: 63 stable prevalent Caucasian anuric patients underwent one 4-h standard bicarbonate HD session. Dialysate K(+) concentration was 2.0 mmol/L in both studies. Blood samples were obtained from the inlet blood tubing immediately before the onset of dialysis and at t60, t120, t180 min and at end of the 4- and 8-h sessions for the measurement of plasma K(+), blood bicarbonates and blood pH. Additional blood samples were obtained at t360 min for the 8 h sessions. Direct dialysate quantification was utilized for K(+)MBs. Direct potentiometry with an ion-selective electrode was used for K(+) measurements. RESULTS: Study A: mean K(+)MBs were significantly higher in the 8-h sessions (4 h: -88.4 ± 23.2 SD mmol versus 8 h: -101.9 ± 32.2 mmol; P = 0.02). Bivariate linear regression analyses showed that only mean plasma K(+), area under the curve (AUC) of the hourly inlet dialyser diffusion concentration gradient of K(+) (hcgAUCK(+)) and AUC of blood bicarbonates and mean blood bicarbonates were significantly related to K(+)MB in both 4- and 8-h sessions. A multiple linear regression output with K(+)MB as dependent variable showed that only mean plasma K(+), hcgAUCK(+) and duration of HD sessions per se remained statistically significant. Study B: mean K(+)MBs were -86.7 ± 22.6 mmol. Bivariate linear regression analyses showed that only mean plasma K(+), hcgAUCK(+) and mean blood bicarbonates were significantly related to K(+)MB. Again, only mean plasma K(+) and hcgAUCK(+) predicted K(+)MB at the multiple linear regression analysis. CONCLUSIONS: Our studies enabled to establish the ranking of factors determining intradialysis K(+)MB: plasma K(+) → dialysate K(+) gradient is the main determinant; acid-base balance plays a much less important role. The duration of HD session per se is an independent determinant of K(+)MB.

Physical activity in chronic kidney disease: a plausible approach to vascular calcification?

Vascular calcification (VC) is a prominent feature that affects up to 40 to 80% of Chronic Kidney Disease (CKD) patients depending on the degree of renal impairment. Though etiology and pathogenesis of the different types of VC are far from being elucidated, it is conceivable that an imbalance between promoters and inhibitors represents the condition that triggers VC deposition and progression. In addition to traditional cardiovascular risk factors, several lines of evidence suggest that specific factors may affect the arterial system and prognosis in CKD. Over the last decade, a few pharmacological strategies aimed at controlling different selected risk factors for VC have been investigated yielding conflicting results. In light of the complicated interplay between inhibitors and promoters as well as the fact that VC represents the result of cumulative and prolonged exposure to multiple risk factors, a more comprehensive risk modification approach such as lifestyle modification or physical activity (PA) may represent a valid strategy to attenuate VC deposition and progression.We herein aim at reviewing the rationale and current evidence on the potential for lifestyle modification with a specific focus on PA as a cost-effective strategy for VC treatment.

[Rescue endovascular revascularization in two patients with bilateral atherosclerotic renal artery occlusion]. / Rivascolarizzazione endovascolare di salvataggio in due pazienti con occlusione aterosclerotica bilaterale dell'arteria renale.

Renal artery stenosis is found in 2% and 40% of general and high cardiovascular risk populations, respectively. Atherosclerotic renal artery stenosis (ARAS) has become an increasingly recognized clinical condition, especially in older or otherwise atherosclerosis-prone populations. This increase in prevalence has led to a dramatically increased use of percutaneous transluminal renal angioplasty. Randomized trials have failed to demonstrate any superiority of renal revascularization over medical therapy as far as control of hypertension, mortality or cardiovascular events is concerned. However, in this report we present two cases in which rescue endovascular revascularization in patients affected by bilateral ARAS permitted withdrawal from hemodialysis treatment and the restoration of a certain degree of renal function. In conclusion, for certain carefully-selected high-risk patients, renal revascularization may still have an important role. The two cases presented in this article are good examples of the extraordinary benefit that endovascular revascularization can bestow.

[A technique for inserting inadvertently removed tunneled hemodialysis catheters through the original exit site]. / Una tecnica per il riposizionamento del catetere venoso centrale tunnellizzato fuoriscito accidentalmente mediante infilaggio dall'exit site.

Accidental loss of tunneled hemodialysis (HD) central venous catheters (CVCs) is a rare complication. In the absence of other sites available for positioning a new CVC, the lack of a vascular access exposes the patient to a high risk of mortality. The technique for inserting inadvertently removed tunneled CVCs using the original exit site has never gained popularity and has been used, although with good results, in selected cases only. The purpose of this case report is to describe our experience in similar cases, and to propose a variant of the procedure described above: in 4 cases occurring over the last 12 months, our technique permitted recovery of vascular access for up to 72 hours after the loss of the CVC, with placement of a new cuffed CVC performed in the space of a few minutes. There were no cases of bleeding nor episodes of infection. The patients resumed their regular HD program with adequate performance of the CVC during a follow-up period that ranged from 3 to 12 months.In conclusion, we believe that this simple manoeuvre can help the nephrologist solve one of the dialysis room's moments of genuine emergency.

Fibromuscular dysplasia of renal arteries presenting with bilateral renal infarction in a young man.

Fibromuscular dysplasia (FMD) describes a group of conditions which cause nonatheromatous arterial stenoses, most commonly of the renal and carotid arteries, typically in young women. We report the case of a previously healthy 43-year-old white man presenting with acute bilateral flank pain. The pain was more severe on the left side. Initially treated for ureteral colic, he was transferred to the nephrology unit upon recognition of a rising serum creatinine. He was found to have FMD of bilateral renal arteries with resultant infarctions in both kidneys. He was treated with intravenous heparin and, then, warfarin at discharge. At a 16-month review, the patient remained pain-free with normal renal function and with antiplatelet and dual antihypertensive therapy. In conclusion, renal infarction complicating FMD is rare, with most cases involving causative cardiovascular risk factors, including coagulopathy, ischemic heart disease, atrial fibrillation or structural cardiac abnormalities, none of which was present in this case. What makes this case interesting are the clinically significant bilateral renal infarctions due to atypical asymmetric FMD in both kidneys in a young man.

Sodium setpoint and gradient in bicarbonate hemodialysis.

BACKGROUND: The demonstration of an individual osmolar setpoint in hemodialysis (HD) is crucial to individualize dialysate sodium concentrations. Furthermore, the diffusive gradient between plasma and dialysate sodium is important in the "fine tuning" of the intradialytic sodium mass balance (MB). METHODS: The design of this study included part A: a retrospective analysis of predialysis plasma sodium concentrations extracted from a 6-year database in our HD population (147 prevalent white anuric patients); and part B: study of intradialytic sodium kinetics in 48 patients undergoing one 4-hour bicarbonate HD session. Direct potentiometry with an ion-selective electrode was used for sodium measurements. RESULTS: Study part A: the mean number of plasma sodium measurements per patient was 16.06 ± 14.03 over a mean follow-up of 3.55 ± 1.76 years. The mean of the averaged plasma sodium concentrations was 136.7 ± 2.1 mmol/L, with a low mean intraindividual coefficient of variation (1.39 ± 0.4). Study part B: mean predialysis and postdialysis plasma sodium concentrations were 135.8 ± 0.9 and 138.0 ± 0.9 mmol/L (p<0.001). Mean inlet dialyzer sodium concentration was 138.7 ± 1.1 mmol/L; the hourly diffusion concentration gradients showed a statistically significant transfer from dialysate to plasma (Wilks ? <0.0001). A statistically significant relationship was found between sodium MB and diffusion gradient (p<0.02), and between sodium MB and ultrafiltration volume (p<0.01). CONCLUSIONS: A relatively "fixed" and individual osmolar setpoint in HD patients was shown for the first time in a long-term follow-up. A dialysate sodium concentration of 140 mmol/L determined a dialysate to plasma sodium gradient.

The systemic capillary leak syndrome: a scarcely known nephrological entity.

The idiopathic systemic capillary leak syndrome (SCLS) is a rare life-threatening disorder characterized by periodic episodes of hypovolemic shock, due to plasma leakage from the intravascular to the interstitial space, as reflected by accompanying hypoalbuminemia, hemoconcentration and edema. Here we report the case of a 65-year-old woman affected by SCLS who required aggressive resuscitation with norepinephrine, steroids, albumin and crystalloids. Then, a long-term prophylaxis with a ß(2)-adrenergic receptor agonist and theophylline was started. In conclusion, though SCLS is a rare entity, the associated morbidity and mortality require the physician's awareness to provide timely therapy. Underrecognition in the medical community and rarity of this syndrome have precluded analysis by rational clinical trial designs that are necessary to determine more targeted and adequate therapy. This report is meant to enhance awareness of SCLS in the nephrology community.