Kai Ming Chow

Tuberculous Peritonitis–Associated Mortality Is High among Patients Waiting for the Results of Mycobacterial Cultures of Ascitic Fluid Samples

We identified 60 cases of tuberculous peritonitis during the past 12 years at our health care center. Most of the patients had severe underlying medical conditions, such as cirrhosis, renal failure, diabetes mellitus, and malignancy. Abnormal chest radiograph findings, ascitic fluid lymphocytosis, and biochemical findings for exudates could only identify 33%, 37%, and 53% of the cases, respectively. On the other hand, peritoneal biopsy allowed early definitive diagnosis for 9 patients. Thirty-one patients died, 26 of whom died < or =6 weeks after their initial presentation, often before the result of mycobacterial culture was available. Only 8 patients died of advanced disease after antituberculous therapy was started. Univariate analysis showed that advanced age, underlying diagnosis, and delayed initiation of therapy were associated with higher mortality rates. Standard antituberculous chemotherapy is highly effective. However, conventional microbiologic diagnostic methods are slow and not sensitive enough for establishing a diagnosis of tuberculous peritonitis.

Expression of MicroRNAs in the Urinary Sediment of Patients with IgA Nephropathy

Background: Micro-RNAs (miRNAs) regulate one-third of all protein-coding genes and are fundamental in the pathophysiology of a wide range of diseases. We studied the expression of several miRNA species (miR-200 family, miR-205 and miR-192) in the urinary sediment of patients with IgA nephropathy (IgAN). Methods: We studied 43 patients with biopsy-proven IgAN. Urinary expression of miRNAs was determined and compared to that from 13 healthy controls. Results: The levels of urinary miR-200a, miR-200b and miR-429, but not miR-200c, miR-141, miR-205, or miR-192, were down-regulated in patients with IgAN. Proteinuria significantly correlated with urinary expression of miR-200a (r = −0.483, P < 0.001), miR-200b (r = −0.448, P = 0.001) and miR-429 (r = −0.466, P = 0.001). Baseline renal function significantly correlated with urinary expression of miR-200b (r = 0.512, P < 0.001) and miR-429 (r = 0.425, P = 0.005). Urinary gene expression of ZEB2 inversely correlated with miR-200b (r = −0.321, P = 0.017); and vimentin expression inversely correlated with that of miR-200a (r = −0.360, P = 0.007), miR-200b (r = −0.416, P = 0.002) and miR-429 (r = −0.375, P = 0.005). After 33.4 ± 12.6 months, the rate of renal function decline significantly correlated with urinary expression of miR-200b (r = 0.316, P = 0.034). Conclusions: Urinary expression of miR-200a, miR-200b and miR-429 were down-regulated in patients with IgAN, and the degree of reduction correlated with disease severity and rate of progression. The results suggested that these miRNA species might play important roles in the pathophysiology of IgAN. Further studies are needed to clarify the role of urinary miRNA repression as a non-invasive marker of IgAN.

Indication for peritoneal biopsy in tuberculous peritonitis

BACKGROUND With the introduction of effective antituberculous chemotherapy, the clinical outcome of tuberculous peritonitis depends much on the diagnostic accuracy of this disease entity. This review summarizes the current state-of-the-art thinking regarding the protean manifestation and diagnostic modalities of this major infectious disease. DATA SOURCES This review was compiled after an extensive search of the current and historical literature, comprising 1,070 cases of tuberculous peritonitis. A number of important areas were highlighted, with emphasis on the diagnostic value and clinical impact of peritoneal biopsy. CONCLUSIONS We believe an aggressive diagnostic approach, particularly with peritoneal biopsy, is warranted for the diagnosis and timely treatment of tuberculous peritonitis.

Antibody Response to Hepatitis B Vaccine in End-Stage Renal Disease Patients

Background: This retrospective and comparative study evaluated the relationship between different factors which may contribute to suboptimal immunological response to intramuscular recombinant hepatitis B vaccine in end-stage renal disease (ESRD) subjects. Methods: From a cohort of 64 dialysis subjects undergoing primary vaccination with Engerix-B®, we determined the predictive factors that impinged on patients’ response to vaccine, as defined by anti-HBs level ≧10 mIU/l. Dose efficacy was further evaluated by comparing three historical cohorts vaccinated by the regimens of 20, 40 and 80 µg/dose, respectively. Results: We identified 64 ESRD patients (mean age 43 ± 12 years, 81% receiving peritoneal dialysis) who received primary vaccination from April 1997 to September 2004. Median follow-up was 6.5 years. They achieved 81% seroconversion rate. Older age, diabetes mellitus, obesity and low Engerix-B dose were risk factors of inadequate anti-HBs response by univariate analysis. By stepwise logistic regression analysis, hepatitis B vaccine dose was the only independent predictive factor of impaired antibody response. An Engerix-B vaccine dose of 20 µg was associated with more than tenfold increase in risk of non-response to hepatitis B vaccine (hazards ratio 32.2 (95% CI 3.85–250.0)). Immunization with 80 µg of Engerix-B increased the likelihood of persistent protective antibody (log-rank test, p = 0.014). Immunization with Engerix-B 80-µg dose is estimated to prevent one extra ESRD subject who would lose seroprotective anti-HBs level at 1 year for every 5.6 patients treated (number needed to treat to benefit, 5.6 (95% CI 5.4–5.8)). Conclusions: Our results suggest the potential for the three-dose schedule of recombinant vaccine Engerix-B 80 µg to prolong the immune response among ESRD population.

Predictive Value of Dialysate Cell Counts in Peritonitis Complicating Peritoneal Dialysis

Early prediction of outcomes has major potential implications regarding the management of dialysis-related peritonitis. The outcomes of 565 consecutive episodes of peritonitis complicating peritoneal dialysis between August 2001 and July 2005 were evaluated in relation to the dialysate cell counts. Discriminatory power, based on the area under the receiver-operating characteristic (ROC) curves, of the cell counts was assessed. The findings then were validated externally in a cohort of 217 peritonitis episodes from another dialysis unit. During the study period, 565 episodes of peritonitis were included for analysis, 465 of which had treatment success defined as complete resolution of peritonitis without the need for Tenckhoff catheter removal. Of the remaining 100 episodes (treatment failure), 70 required Tenckhoff catheter removal and 30 had peritonitis-related death. The peritoneal dialysate total white blood cell count on day 3 of peritonitis predicted treatment failure independent of standard risk factors, and it had a higher area under the ROC curve than the dialysate white cell count on day 1 (0.80 versus 0.58; P < 0.0001). Using a peritoneal dialysate white count cut point > or = 1090/mm3 on day 3, the sensitivity was 75% and the specificity was 74% for the prediction of treatment failure (defined as catheter loss or peritonitis-related death). In multiple logistic regression analyses, peritoneal dialysate white count > or = 1090/mm3 on day 3 was an independent prognostic marker for treatment failure after adjustment for conventional risk factors (hazard ratio 9.03; 95% confidence interval 4.40 to 18.6; P < 0.0001). Number of years on peritoneal dialysis; diabetes; gram-negative organisms; and Pseudomonas, fungal, or Mycobacterium species were other independent risk factors that were predictive of treatment failure. Findings from an independent validation set of peritonitis (217 episodes after exclusion of Mycobacterium and fungal causes) also favored the peritoneal dialysate white count on day 3, as compared with day 1 and day 2, to predict treatment failure. Area under the ROC curve for the white counts on day 3 was 0.98 (95% confidence interval 0.95 to 0.99) in the validation set. This study demonstrated and cross-validated the superiority of peritoneal dialysate white cell count on day 3 to predict outcomes of dialysis-related peritonitis. These results call attention to the value of validating prognostic factors of peritonitis complicating peritoneal dialysis.

Asian chronic kidney disease best practice recommendations: Positional statements for early detection of chronic kidney disease from Asian Forum for Chronic Kidney Disease Initiatives (AFCKDI)

1. Targets

Pathogenesis and management of hydrothorax complicating peritoneal dialysis.

Purpose of review Hydrothorax complicating continuous ambulatory peritoneal dialysis (CAPD) appears in approximately 2% of all patients. Recent advances in minimally invasive surgery have revolutionized the treatment strategy of this condition. Recent findings Hydrothorax in CAPD is most commonly secondary to a pleuro-peritoneal communication. Thoracocentesis with biochemical analysis of pleural fluid is the first-line investigation. In uncertain cases, or when there is a clinical need to demonstrate the anatomy of the communication, an imaging approach such as peritoneal scintigraphy is required. Cessation of peritoneal dialysis is indicated if diagnosis of the complication is confirmed. For half of the cases, a conservative approach allows reinstitution of CAPD, presumably because of spontaneous resolution of the leakage. A small-volume exchange is a feasible alternative for children. In patients who failed conservative treatment, video-assisted thoracoscopic pleurodesis or diaphragmatic repair or both allows most of them to continue with CAPD. Chemical pleurodesis is probably indicated for those who failed conservative treatment in centers without video-assisted thoracoscopic support. Currently, only a minority of patients will require open thoracotomy. Summary Once hydrothorax secondary to pleuro-peritoneal communication is confirmed in CAPD patients, temporary cessation of peritoneal dialysis remains the first-line treatment. Current evidence shows that video-assisted thoracoscopic pleurodesis or repair should be the treatment of choice in patients who failed conservative management.

Infectious complications in dialysis—epidemiology and outcomes

This Review focuses on the changing epidemiology of infections among patients with end-stage renal disease who are undergoing dialysis. In particular, bloodstream infections related to vascular access in patients undergoing hemodialysis, and peritonitis in patients undergoing peritoneal dialysis, are highlighted. Gram-positive (staphylococcal and enterococcal) bloodstream infections and Gram-negative peritonitis (especially extended-spectrum β-lactamase-producing organisms) contribute substantially to excess health-care use owing to infection caused by dialysis access. Although the management of peritoneal-dialysis-related peritonitis has been hampered by a dearth of randomized, controlled studies, epidemiological data have provided useful information. To overcome the problem of differing methods used to monitor infections within various dialysis centers, uniform reporting systems for vascular-access-related infection and peritoneal-dialysis-related peritonitis, as recommended by the Centers for Disease Control and Prevention and the International Society for Peritoneal Dialysis, respectively, are discussed. Infections unrelated to the port of entry for dialysis are also examined, namely hepatitis and respiratory infection. To address the disease burden, we examine the infection-related mortality as well as the implications for subsequent cardiovascular mortality.

Review Articles: Management Options for Hydrothorax Complicating Peritoneal Dialysis

Hydrothorax as a result of pleuroperitoneal communication occurs in approximately 2% of continuous ambulatory peritoneal dialysis (CAPD) patients. Although our understanding of its mechanisms is incomplete, it is apparent that the key to successful therapy is obliteration of a transdiaphragmatic route of dialysate leakage (pleuroperitoneal communication), possibly coupled with reduction of intra‐abdominal pressure. This review corroborated the findings from 10 major population‐based case series in which 60 of the 104 cases (58%) were able to resume long‐term peritoneal dialysis (PD). Temporary interruption of PD alone was successful in half of them. As compared to this conservative approach, as well as chemical pleurodesis via intercostal chest drain, video‐assisted thoracoscopic intervention (including direct pleurodesis and diaphragmatic repair) has shown a promising role. Efficacy of thoracoscopic treatment has been confirmed by several case series from various centers and the demonstration of a success rate in excess of 90%. With accumulating experience using the thoracoscopic technique, it remains to be seen whether this mode of treatment will obviate the traditional closed pleurodesis.

Evaluation of two protocols of uremic rat model: partial nephrectomy and infarction.

Animal models of chronic renal failure have been mostly achieved by partial ablation of renal parenchyma, the two most common techniques employed being surgical resection or infarction. Evaluation of the uremic model using these two techniques was carried out in Wistar rats. Two weeks after operative procedure, measured serum urea levels in the resection and infarction models were 59.1 and 64.3 mg/dL (normal range 15.6–24.4 mg/dL) respectively. However, the standard deviation in the former was significantly lower, 6.3 vs. 97.1 mg/dL from infarction model, p = 0.007. A consistent degree of glomerular filtration rate reduction was obtained in the resection model, resulting in 20–30% of normal creatinine clearance. This compared favorably with the creatinine clearance range (0.3–74% of normal) from the infarction model, in which two animals died of uremia and seven had higher than 50% of normal creatinine clearance. It is reasonable to attribute reproducibility and homogeneity demonstrated in the resection model to (i) more precise control of renal ablation extent with surgical techniques and (ii) less interplay of confounding injury mechanism to remnant kidney. These data support superiority of the resection model as an experimental tool for pathophysiological and/or interventional investigations of chronic renal failure.