We review BK-virus nephropathy (BKN) as a new complication that increasingly affects renal allografts and causes dysfunction. Since starting in 1996, we have seen 11 cases. Currently, the prevalence of BKN is 3% in our graft biopsies. The diagnosis can only be made histologically. The virus affects tubular epithelial cells that show characteristic intranuclear inclusion bodies. The major reason for impaired graft function and a possible way for viral particles to gain access to the blood via peritubular capillaries is necrosis of infected epithelial cells. BK-virus DNA in the plasma, which can be detected by PCR, is closely associated with nephropathy. BK-virus does not stimulate tubular MHC-class II expression as judged by immunofluorescence double labelling. The inflammatory response is inconsistent and the frequency of rejection episodes is not increased during disease. Clinical manifestation of viral nephropathy evolves in several stages. (i) Initial, asymptomatic and reversible activation of the virus, judged by the presence of inclusion bearing cells in the urine. (ii) High dose immunosuppressive drug regimens, often including tacrolimus. (iii) Tubular injury and viraemia as additional promoting conditions. BKN nephropathy was associated with graft loss in 45% of our patients. The remaining patients with persistent viral nephropathy showed renal dysfunction (serum creatinine levels on average 150% above baseline readings). Currently, no established antiviral therapy is available. We discuss attempts to lower immunosuppression as a means to control viral replication. We propose a diagnostic algorithm for screening and monitoring the disease.

Videolaparoscopy prolongs peritoneal catheter survival by treating directly the causes of malfunction. In patients with preceding abdominal interventions, the PD catheter can be placed safely even in cases necessitating surgical preparation like adhesiolysis.

Long-term dialysis treatment can be associated with several musculoskeletal complications. Entheseal involvement in dialysis patients remains rarely studied as its prevalence is underestimated due to its often asymptomatic presentation. The aims of the study were to determine the prevalence of subclinical enthesopathy in haemodialysis and peritoneal dialysis patients at the lower limb level, to investigate the inter-observer reliability of ultrasound assessment and to analyse the influence of biometric and biochemical parameters. Ultrasound examination was conducted at the entheses of the lower limbs level in 33 asymptomatic dialysis patients and 33 healthy adopting the Glasgow Ultrasound Enthesitis Scoring System (GUESS). The inter-observer reliability was calculated in 15 dialysis patients. Ultrasound found at least one sign of enthesopathy in 165 out of 330 (50%) entheses of dialysis patients. In healthy subjects, signs of enthesopathy were present in 54 out of 330 (16.3%) entheses (p < 0.0001). No power Doppler signal was detected in healthy controls, in contrast to four of 330 entheses of dialysis patients. No US signs of soft tissue amyloid deposits were found. The GUESS score was significantly higher in dialysis patients than in controls (p < 0.0001). There was no difference in terms of enthesopathy between haemodialysis and peritoneal dialysis. Dialysis duration resulted to be the most important predictor for enthesopathy (p = 0.0004), followed by patient age (p = 0.02) and body mass index (p = 0.035). Parathormone, calcium, phosphorus, C-reactive protein, cholesterol and triglycerides apparently did not play a relevant role in favour of enthesopathy. The inter-observer reliability showed an excellent agreement between sonographers with different degree of experience. Our results demonstrated a higher prevalence of subclinical enthesopathy in both haemodialysis and peritoneal dialysis patients than in healthy subjects. Follow-up will provide further information with respect to the predictive value of US findings for the development of symptomatic dialysis-related arthropathy.

In general, the laparoscopic technique is associated with longer operative times, higher costs and the need to utilize general anesthesia. It is, however, the preferred method when rescuing malfunctioning catheters and may increase the PD patient population in patients with previous abdominal surgeries. The dialysis access surgeon should be familiar with both open and laparoscopic techniques and appropriately choose the ideal method based upon the individual patient and institutional resources.

Gray scale ultrasound has an important diagnostic role in native kidney disease. Low cost, absence of ionizing radiation and nephrotoxicity, short performance time, and repeatability even at the bedside, are the major advantages of this technique. The introduction of contrast enhancement ultrasound (CEUS) in daily clinical practice has significantly reduced the use of contrast enhancement computed tomography (CECT) and contrast enhancement magnetic resonance (CEMR), especially in patients with renal disease. Although there are many situations in which CECT and CEMRI are primarily indicated, their use may be limited by the administration of the contrast medium, which may involve a risk of renal function impairment, especially in the elderly, and in patients with acute kidney injury (AKI) and moderate to severe chronic kidney disease (CKD). In these cases, CEUS can be a valid diagnostic choice. To date, numerous publications have highlighted the role of CEUS in the study of parenchymal micro-vascularization and renal pathology by full integration with second level imaging methods (CECT and CEMRI) both in patients with normal renal function and with diseased kidneys. The aim of this review is to offer an updated overview of the limitations and potential applications of CEUS in native kidney disease.

Malfunction of the peritoneal dialysis catheter is frequently caused by dislocation. The diagnostic approach is classically based on abdomen X-ray together with detailed case history and physical examination. Despite being rarely applied in clinical practice to evaluate catheter misplacement, ultrasound is a noninvasive, radiation-free technique that is potentially useful also to explore reasons for catheter malfunction. Consequently, we aimed to evaluate the diagnostic accuracy of ultrasound to identify peritoneal catheter misplacement. In a multicenter observational blinded study, we compared ultrasound to abdomen X-ray for catheter localization in 93 consecutive peritoneal dialysis patients with dialysate outflow problems enrolled in two nephrology and dialysis units. The position of the catheter was annotated on a standard scheme of nine abdominopelvic regions. The sensitivity, specificity, positive and negative predictive value and Kappa coefficient were calculated. Dislocation out of the inferior abdominopelvic regions was present in 19 patients (20 %) at X-ray and 23 patients (25 %) at ultrasound. Correct determination of the position of the catheter in the lower abdomen by ultrasound had a sensitivity of 93 % (95 % CI 84 - 97 %), specificity of 95 % (95 % CI 72 - 100 %), positive predictive value of 99 % (95 % CI 91 - 100 %), negative predictive value of 78 % (95 %CI 56 - 92 %) and Kappa coefficient of 0.82 (95 % CI 0.67 - 0.96). In 10 out of 93 patients (11 %), there was a position mismatch between X-ray and ultrasound in an adjacent abdominopelvic region. Our results suggest that abdomen X-ray for the evaluation of peritoneal catheter position can be replaced by ultrasound in experienced hands. This bedside diagnostic procedure might reduce costs, the time necessary for diagnosis and lifetime radiation exposure.

No abstract

ABSTRACT. The immunohistochemical detection of the complement degradation product C4d, a component of the classical complement pathway, offers a new and currently poorly defined tool in the evaluation of renal allograft biopsies. Our retrospective study aims at determining the diagnostic and clinical significance of C4d accumulation in kidney transplants, employing immunofluorescence microscopy. We analyzed 398 diagnostic allograft biopsies (n = 265 patients with 1 to 5 biopsies obtained 7 to 7165 d posttransplantation [tx]) and correlated the detection of C4d with 18 histologic changes, panel-reactive antibody titers, response to treatment, and outcome. One hundred twenty-five native kidney and baseline tx biopsies served as controls. Linear deposition of C4d along peritubular capillaries was only found in a subgroup (30%) of allografts post-tx, mainly during the early time-course (median, 38 d post-tx; range, 7 to 5646 d). There was no significant association with infections. C4d staining could change from negative to positive and vice versa within days to weeks. The accumulation of C4d was most tightly linked to a morphologic subtype of rejection, transplant glomerulitis (P < 0.0001). In addition, tubular MHC class II expression was correlated with C4d deposition (P < 0.0001). Both features are signs of “acute active rejection.” In comparison with C4d-negative controls, 43% of C4d-positive patients showed increased (>10%) panel-reactive antibody titers (versus 19% in the negative group; P = 0.001). C4d positivity was frequently associated with higher serum creatinine levels at time of biopsy (compared with C4d-negative group; P < 0.01). More C4d-positive patients were treated with polyclonal antithymocyte globulins (ATG) or monoclonal anti-CD3 antibodies (OKT3) (P < 0.0001). Outcome did not significantly differ between C4d-positive and C4d-negative groups. In conclusion, the detection of C4d identifies a humoral alloresponse in a subgroup of kidney transplants, which is often associated with signs of cellular rejection, i.e. tx glomerulitis. Allograft dysfunction in C4d-positive rejection episodes is often more pronounced. We provide first evidence that C4d-positive rejection might benefit from intensive therapy, potentially preventing the previously reported high graft failure rate. In addition, we show that a subgroup of C4d-positive cases may not require any immediate therapeutic intervention. The presence of C4d is clinically relevant and should be reported in the histologic diagnosis.