Ping-Nam Wong

Hepatitis B virus infection in dialysis patients

Abstract  Hepatitis B virus (HBV) infection remains a major issue among dialysis patients. It is associated with a high risk of hepatic complication. The liver disease runs a unique clinical course in dialysis patients, as it can progress with modest hepatic inflammation and prominent fibrosis. The conventional cut‐off level of serum alanine aminotransferase (ALT) for commencing antiviral therapy may prove too high and inappropriate for dialysis patients, and liver biopsy appears to be the only definitive means to establish the activity of liver disease in dialysis patients. Liver biopsy should be considered in patients with a serum ALT level that is persistently greater than 30 IU/L, or 0.75‐fold the upper limit of the normal level, and/or other clinical and laboratory findings that suggest active liver disease. For antiviral treatment, preliminary reports have shown that lamivudine is effective and well tolerated in dialysis patients. However, the long‐term efficacy of lamivudine and its optimal effective dose in dialysis patients remain unknown. The prevention of nosocomial transmission among dialysis patients is also important. Universal precaution measures should be strictly observed and the segregation of hepatitis B surface antigen‐positive hemodialysis patients should be considered. For HBV non‐immune patients, the importance of HBV vaccination should not be overemphasized. Until a new generation of highly immunogenic vaccines that are proven to be safe and effective in patients with end‐stage renal disease becomes available, early vaccination before the development of end‐stage renal failure remains the best way to secure immunological protection against HBV infection in dialysis patients.

Hong Kong Renal Registry Report 2010

This report examines the characteristics and trends of dialysis and renal transplant patients among the resident population of Hong Kong who were managed by hospitals or dialysis centers of the Hospital Authority of Hong Kong, and who accounted for approximately 95% of all patients who received renal replacement therapy (RRT) in the territory. Patients who received RRT solely in the private sector were not included in this report. Data trends from 1996 to 2009 are presented. In 2009, 930 new patients were accepted into RRT programs and the incident rate was 132.4 patients per million population (pmp). This is lower than the incident rate in 2008, which was 148.2 pmp. The point prevalence as of December 31, 2009 was 7,580, with a prevalence rate of 1,078.8 pmp. There were 3,401 patients on peritoneal dialysis (PD, 44.9%), 945 patients on hemodialysis (HD, 12.5%), and 3,234 patients living with a functioning renal transplant. The PD to HD ratio was 81.5:18.5 for patients on dialysis treatment at Hospital Authority centers. PD-first policy continued. The overall mortality rate among RRT patients was 10.7 patients per 100 patient-years exposed. There was a decreasing trend in mortality among PD patients. Infection and cardiovascular complications were the most common causes of death. Renal transplant was the modality with the best survival. The 5-year cumulative patient survival rate for patients on transplant treatment was 88%, whereas the corresponding patient survival rates for PD and HD patients were 37% and 34.2%, respectively. More than 80% of RRT patients with reports on rehabilitation were active and had normal activities.

Hong Kong Registry Report 2004

This report is based on data (up to 31 March 2004) from the Renal Registry of the Hospital Authority of Hong Kong, and accounts for 90-95% of all patients receiving renal replacement therapy (RRT) in the territory. Patients receiving RRT in the private sector are not included in this report. The number of patients receiving RRT was 6,054 (889 per million population [pmp]), of whom 51.6% (3,123, 451 pmp) were receiving peritoneal dialysis (PD), 10.9% (662, 97 pmp) hemodialysis (HD), and 37.5% (2,269, 334 pmp) had functioning kidney transplants. The net increase from the previous year in the number of patients receiving RRT was 3.1%. The incidence of end-stage renal failure in patients undergoing RRT was 954 (140 pmp). The median ages of existing and new patients receiving RRT were 55 and 56 years, respectively. There was a trend towards an increasing number of elderly dialysis patients. Diabetes was the third major cause of renal failure among existing RRT patients and the most common cause of renal failure in new cases. The rate of serologic positivity for hepatitis B infection in RRT patients was 9.68%, while that for hepatitis C infection was 3.28%. In Hong Kong, most patients were put on PD when RRT was required. Of all patients on dialysis, 83% were on PD, of whom 94.8% were on continuous ambulatory peritoneal dialysis (CAPD). Most CAPD patients were on disconnect systems. HD was used in 17.5% of all patients on dialysis. Of the 2,269 patients with functioning kidney transplants, 836 (36.8%) were transplanted in Hong Kong. Of these, 495 (59.2%) had undergone cadaveric kidney transplantation. Of all patients receiving RRT, 30% were receiving erythropoietin. For the year ending 31 March 2004, the annual crude mortality rate for all RRT was 10% (15.3% for PD, 13% for HD, and 1.9% for transplantation). The major causes of death were infection, cardiovascular disease, and cerebrovascular accident. The 1- and 5-year survival rates for patients with kidney transplantation performed in Hong Kong between 1 April 1997 and 31 March 2003 were 98.6% and 96.5%, respectively, for living related kidney transplants, and 96.1% and 91.2%, respectively, for cadaveric kidney transplants. The 1- and 5- year graft survival rates were 91.1% and 86.1% (death censored) and 90.5% and 85.6% (death not censored) for living related kidney transplants, and 89% and 83% (death censored) and 86% and 79% (death not censored) for cadaveric kidney transplants. The overall peritonitis rate for all chronic PD systems for the year ending 31 March 2004 was one episode per 27.7 months.

Long-term follow-up of thoracoscopic pleurodesis for hydrothorax complicating peritoneal dialysis

BACKGROUND Massive hydrothorax is a significant complication of continuous ambulatory peritoneal dialysis (CAPD) and its ideal management remains undefined. Conservative management in the form of intermittent peritoneal dialysis had limited success. The use of conventional pleurodesis and open thoracotomy were associated with morbidities and limitations. We retrospectively reviewed the long-term outcome of 8 patients with massive hydrothorax complicating CAPD, 6 of whom received thoracoscopic pleurodesis. METHODS Among 397 patients undergoing continuous ambulatory peritoneal dialysis during the period from 1994 to 1998, hydrothorax developed in 8 patients. Four patients were first treated with temporary intermittent peritoneal dialysis using 1-L exchange cycles. Three of them had a recurrence of the hydrothorax whereas only one could resume continuous ambulatory peritoneal dialysis successfully. Two patients then underwent conventional pleurodesis but failed. One of them was switched to hemodialysis. Thoracoscopic pleurodesis was performed for the remaining 2 patients together with 4 other patients with hydrothorax once this complication developed. There were no gross abnormalities including pleuroperitoneal communication sites identified. Talc poudrage was performed in 2 patients and mechanical rub pleurodesis in the other 4 patients. All had uncomplicated procedure and uneventful recovery. RESULTS One patient after thoracoscopic pleurodesis was soon switched to hemodialysis for an unrelated reason. The other 5 patients resumed continuous ambulatory peritoneal dialysis with no recurrence of hydrothorax for a mean period of 50 months (range 19 to 84). CONCLUSIONS With thoracoscopic pleurodesis, patients resumed continuous ambulatory peritoneal dialysis without recurrence of hydrothorax on long-term follow-up.

Efficacy of enteric‐coated mycophenolate sodium in patients with active lupus nephritis

Background:  The ideal treatment of lupus nephritis has yet to be defined. Both cyclophosphamide and mycophenolate mofetil have been used with encouraging results, but adverse events are frequently seen. There are no data on the use of enteric‐coated mycophenolate sodium.

Clinical presentation and outcome of severe acute respiratory syndrome in dialysis patients

Abstract There was a major outbreak of severe acute respiratory syndrome (SARS) affecting more than 300 patients occurring in a private housing estate in Hong Kong, in which an infected renal patient was suspected to be the primary source. It is unknown whether renal patients would represent a distinct group of patients who share some characteristics that could predispose them to have higher infectivity. In this context, we have encountered 4 dialysis patients contracting SARS in a minor outbreak, which involved 11 patients and 4 health care workers, in a medical ward of a regional hospital. Of these 4 dialysis patients, 1 patient was receiving hemodialysis while the other 3 patients were on continuous ambulatory peritoneal dialysis. Fever and radiological changes were their dominant presenting features. All were having positive results for SARS-associated coronavirus ribonucleic acid by reverse transcriptase-polymerase chain reaction performed on their nasopharyngeal aspirates or stool samples. It appeared that treatment with high-dose intravenous ribavirin and corticosteroids could only resolve the fever, but it could not stop the disease progression. All 4 patients developed respiratory failure requiring mechanical ventilation on days 9 through 12. At the end, all of the patients died from sudden cardiac arrest, which was associated with acute myocardial infarction in 2 cases. From this small case series, it appeared that dialysis patients might have an aggressive clinical course and poor outcome after contracting SARS. However, a large-scale study is required to further examine this issue, and further investigation into the immunologic abnormalities associated with the uremic state in this group of patients is also warranted.

Persistent Sterile Peritoneal Inflammation After Catheter Removal for Refractory Bacterial Peritonitis Predicts Full-Blown Encapsulating Peritoneal Sclerosis

♦ Background: Encapsulating peritoneal sclerosis (EPS) is the most serious complication of peritoneal dialysis, having high morbidity and mortality. To improve outcomes, early diagnosis is needed to direct treatment during the early inflammatory phase. However, in the early inflammatory phase, clinical features are nonspecific, and no reliable diagnostic criteria have been established. Because bacterial peritonitis and termination of dialysis are two important risk factors triggering the progression of EPS, patients with refractory bacterial peritonitis necessitating dialysis catheter removal are at particularly high risk of developing EPS. Many of these patients might indeed experience non-resolving sterile peritonitis (probably the inflammatory phase of EPS) before progression to full-blown disease (that is, the presence of intestinal obstruction). We undertook a retrospective study to compare, in this particular situation, the clinical characteristics of patients with or without sterile peritoneal inflammation, assessing their clinical outcomes in terms of short-term mortality and the chance of developing full-blown EPS. ♦ Methods: Our retrospective review included 62 patients whose dialysis catheter was removed because of refractory peritonitis between January 2005 and December 2010. ♦ Results: Of the 62 patients identified, 39 (63%) had persistent sterile peritoneal inflammation (“high-risk” group, n = 39), and 23 (37%) had resolution of inflammation without significant intra-abdominal collection after catheter withdrawal (“control” group, n = 23). Compared with the control group, the high-risk group had a significantly longer PD duration (71.6 ± 43.3 months vs 42.3 ± 29.9 months, p = 0.003), a higher dialysate-to-plasma ratio (D/P) of creatinine (0.768 ± 0.141 vs 0.616 ± 0.091, p = 0.004), and a higher computed tomography score for EPS (7.69 ± 2.98 vs 1.00 ± 1.00, p < 0.001). During the 6-month study period, the high-risk group had a higher chance of developing full-blown EPS (31% vs 0%, p = 0.002) and a higher 6-month all-cause mortality (36% vs 4.3%, p = 0.004). ♦ Conclusions: Persistent sterile peritoneal inflammation was common after dialysis catheter removal for refractory bacterial peritonitis, and the patients with such inflammation were at high risk of progression to full-blown EPS.

ATYPICAL MYCOBACTERIAL EXIT-SITE INFECTION AND PERITONITIS IN PERITONEAL DIALYSIS PATIENTS ON PROPHYLACTIC EXIT-SITE GENTAMICIN CREAM

We report 9 cases of exit-site infection and continuous ambulatory peritoneal dialysis peritonitis associated with atypical mycobacteria. All patients had been using topical gentamicin cream as prophylaxis for exit-site infection before the onset of these infections. Gentamicin cream is postulated to be a potential risk factor for atypical mycobacterial infection because of selective pressure on other micro-organisms. The microbiology of atypical mycobacteria and the treatment for atypical mycobacterial infections are discussed.

Successful treatment of oral acetic acid poisoning with plasmapheresis

Abstract Injudicious use of acetic acid can result in acute or chronic poisoning. Chronic ingestion of large amount of 5% acetic acid has been reported to be a cause for hypokalemia, hyper-reninemia and osteoporosis. Acute poisoning can occur after percutaneous treatment of hepatocellular carcinoma or after oral ingestion. Most of the reported cases are from Russia before 1980s. We report an adult with acute accidental poisoning with 30% acetic acid leading to severe intravascular hemolysis, hemoglobulinuria, acute hepatitis, coagulopathy, and acute gastrointestinal bleeding and acute renal failure. Plasmapheresis was started soon after intoxication with good recovery and we discuss its possible role in the management of acetic acid poisoning.

Treatment with Cyclophosphamide in Elderly-Onset Nephrotic Syndrome

Background:The best treatment of elderly-onset nephrotic syndrome has not been well defined. The use of corticosteroids or combination immunosuppressants may be associated with a significant incidence of side effects in the elderly. There is little data on the use of cyclophosphamide alone. Methods:We retrospectively reviewed 30 patients with idiopathic elderly-onset nephrotic syndrome treated with cyclophosphamide. Results:Male to female ratio was 2:1, mean age at diagnosis was 72.7 ± 5.9 years and average length of follow-up was 41.4 ± 21.3 months. Significant co-morbidities, including hypertension, were present in 57%. A raised serum creatinine level was found in 57%. Biopsy revealed 15 membranous nephropathy, 4 mesangial proliferative Gn, 5 IgA nephropathy, 3 minimal change nephropathy, 2 focal segmental glomerulosclerosis and 1 C1q nephropathy. Cyclophosphamide was given for 32.0 ± 16.2 weeks with an averaged cumulative dose per patient 177 ± 84 mg/kg BW. Remission (complete or partial) was attained by 40, 63, 80 and 87% of patients within 12, 24, 36 and 48 weeks of treatment, respectively. Eighteen patients attained complete remission and 9 partial remission after treatment. The mean interval to attain first remission (complete or partial) was 18.9 ± 14.6 weeks. This was not affected by age (p = NS) or initial albumin level (p = NS). At the time of last follow-up, all but 2 patients were in complete or partial remission with raised serum creatinine levels in 40%. Conclusions:Cyclophosphamide was effective and well tolerated in the treatment of elderly-onset nephrotic syndrome, with sustained remission and preserved renal function.