Wei-Shun Yang

Verification and evaluation of aldosteronism demographics in the Taiwan Primary Aldosteronism Investigation Group (TAIPAI Group)

Objective: Current data on primary aldosteronism (PA) from Asian populations are scarce. This cohort study clarifies the attributes of patients with PA in a typical Chinese population. Design: An observational cohort study. Methods: The records of patients referred to the Hypertension Clinic from a multi-centre registration in Taiwan from January 1995 to December 2007 were reviewed. All patients with PA were classified into two subtypes: aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism (IHA); their characteristics were compared. Results: Our cohort consisted of 346 patients with PA, 255 with APA and 91 with IHA. The initial hypokalaemia (59% in APA vs. 27.5% in IHA, p < 0.0001) and transtubular potassium gradient (TTKG) (6.30 ± 2.41 in APA vs. 4.91 ± 2.03 in IHA, p = 0.01) were higher in the APA group. Baseline plasma aldosterone concentration (PAC) was also significantly different between the two subgroups (49.96 ± 38.15 ng/dl in APA vs. 34.24 ± 21.47 in IHA, p < 0.0001). Conclusions: In typical Chinese PA patients, the APA subgroup had a higher proportion of hypokalaemia with elevated TTKG and higher PAC as compared with the IHA subgroup. This largest Asian database also demonstrated major differences between the Caucasian and Chinese populations including female predilection, frequent hypokalaemia, and common paralytic myopathy.

Citrobacter peritoneal dialysis peritonitis: rare occurrence with poor outcomes.

Introduction: Non-Pseudomonas gram-negative bacteria are responsible for an increasing proportion of cases of peritoneal dialysis (PD)-related peritonitis. The role of Citrobacter species in the etiology of PD-related peritonitis is often underestimated. In the present study, we aimed to describe the clinical features, laboratory findings, and short- and long-term outcomes in PD-related peritonitis caused by Citrobacter. Methods: A retrospective review of all episodes of PD-related peritonitis caused by Citrobacter from a single center between 1990 and 2010 was performed. Clinical features, microbiological data, and outcomes of these episodes were analyzed. Results: Citrobacter species was responsible for 11 PD-related episodes (1.8% of all peritonitis episodes) in 8 patients. Citrobacter freundii was the most common etiologic species (73%), and mixed growth was found in the other 3 episodes (27%). Approximately half (46%) of the episodes were associated with constipation and/or diarrhea. Of the Citrobacter isolates from all episodes, 54% were resistant to cefazolin, and only 18% were susceptible to cefmetazole. All isolates were susceptible to ceftazidime, cefepime, carbapenem, and aminoglycosides. More than half of the patients (54%) were hospitalized for index peritonitis, and 27% of the episodes involved a change in antibiotic medication. One patient had relapsing peritonitis caused by C. koseri (9%). The mortality rate of PD-related peritonitis caused by Citrobacter was 18%, and 89% of surviving patients developed technique failure requiring a modality switch after an average of 12 months of follow-up (range 1.2-31.2 months). Conclusion: PD-related peritonitis caused by Citrobacter is associated with poor outcomes, including high rates of antibiotic resistance, a high mortality rate, and a high rate of technique failure among survivors during the follow-up period.

VIRIDANS STREPTOCOCCI IN PERITONEAL DIALYSIS PERITONITIS: CLINICAL COURSES AND LONG-TERM OUTCOMES

♦ Background: The clinical courses and long-term outcomes of viridans streptococcus (VS) peritoneal dialysis (PD) peritonitis remain unclear. ♦ Methods: We conducted a retrospective analysis of all PD patients in a single center with gram-positive cocci (GPC) peritonitis between 2005 and 2011, and divided them into 3 groups: VS, other streptococci and other GPC (apart from VS). Clinical characteristics and outcomes of the VS group were compared with the other streptococci and other GPC groups, with prognostic factors determined. ♦ Results: A total of 140 patients with 168 episodes of GPC peritonitis (44% of all peritonitis) were identified over 7 years. Among these, 18 patients (13%) developed VS peritonitis, while 14 patients (10%) developed other streptococcal peritonitis. Patients with VS peritonitis had a high cure rate by antibiotic alone (94%), despite a high polymicrobial yield frequency (28%). We found that VS peritonitis carried a lower risk of Tenckhoff catheter removal and relapsing episodes than other GPC peritonitis (6% vs 11%), and a lower mortality than other streptococci peritonitis (0% vs 7%). However, after the index peritonitis episodes, VS, other streptococci, and other GPC group had a significantly increased peritonitis incidence compared with the period before the index peritonitis (all p < 0.01). Patients with VS peritonitis had a significantly higher incidence of refractory peritonitis compared with other streptococci or other GPC peritonitis in the long term (both p < 0.01). ♦ Conclusions: VS poses a higher risk of subsequent refractory peritonitis after the index episode as compared with other streptococcal or GPC peritonitis. It might be prudent to monitor the technique of these patients with VS peritonitis closely to avoid further peritonitis episodes.

Acinetobacter Peritoneal Dialysis Peritonitis: A Changing Landscape over Time

Background Acinetobacter species are assuming an increasingly important role in modern medicine, with their persistent presence in health-care settings and antibiotic resistance. However, clinical reports addressing this issue in patients with peritoneal dialysis (PD) peritonitis are rare. Methods All PD peritonitis episodes caused by Acinetobacter that occurred between 1985 and 2012 at a single centre were retrospectively reviewed. Clinical features, microbiological data, and outcomes were analysed, with stratifications based upon temporal periods (before and after 2000). Results Acinetobacter species were responsible for 26 PD peritonitis episodes (3.5% of all episodes) in 25 patients. A. baumannii was the most common pathogen (54%), followed by A. iwoffii (35%), with the former being predominant after 2000. Significantly more episodes resulted from breaks in exchange sterility after 2000, while those from exit site infections decreased (P = 0.01). The interval between the last and current peritonitis episodes lengthened significantly after 2000 (5 vs. 13.6 months; P = 0.05). All the isolates were susceptible to cefepime, fluoroquinolone, and aminoglycosides, with a low ceftazidime resistance rate (16%). Nearly half of the patients (46%) required hospitalisation for their Acinetobacter PD-associated peritonitis, and 27% required an antibiotic switch. The overall outcome was fair, with no mortality and a 12% technique failure rate, without obvious interval differences. Conclusions The temporal change in the microbiology and origin of Acinetobacter PD-associated peritonitis in our cohort suggested an important evolutional trend. Appropriate measures, including technique re-education and sterility maintenance, should be taken to decrease the Acinetobacter peritonitis incidence in PD patients.

Intraperitoneal vascular endothelial growth factor C level is related to peritoneal dialysis ultrafiltration.

Background: Local inflammation and neovascularization have a negative influence on peritoneal dialysis (PD). Patients with higher peritoneal transport have higher interleukin-6 (IL-6) and vascular endothelial growth factor-A (VEGF-A) levels in their dialysate. However, the relationship of other members of the VEGF family, such as VEGF-C, to peritoneal transport or ultrafiltration (UF) is yet to be studied. Methods: Peritoneal cytokine and growth factor levels were determined during the peritoneal equilibration test (PET). Ultrafiltration, peritoneal clearance and residual renal function were also considered. Results: Forty-two PD patients were enrolled. They had been on PD for at least 1 month and free of peritonitis for at least 1 month prior to the study. Patients with high or high average PET had higher dialysate IL-6 and VEGF-C. Dialysate IL-6 and VEGF-C correlated negatively with PET and UF. Conclusions: Dialysate VEGF-C is related to higher transport rate and poorer UF. The role of VEGF-C in PD deserves further study.

Combining body mass index and serum potassium to urine potassium clearance ratio is an alternative method to predict primary aldosteronism

BACKGROUND Though aldosterone-renin ratio (ARR) is the current routine screening method for suspicious primary aldosteronism, we hypothesized that the simple formula combining body mass index (BMI) and serum potassium to urine potassium clearance (PUKC) ratio was comparable to ARR. METHODS Records of patients who were referred to the National Taiwan University Hospital for investigation of primary aldosteronism from January 1995 through December 2007 were retrieved. Primary aldosteronism was diagnosed based on the modified 4-corners criteria, otherwise essential hypertension was diagnosed. In both groups, the PUKC/BMI ratio was determined as well as the ARR. Bland-Altman and mountain-plot analysis were used to validate the agreement between ARR and PUKC/BMI. Receiver operating characteristic (ROC) curves were used to compare the sensitivity and specificity of PUKC/BMI and ARR. RESULTS The records for urinary potassium were analyzed for 177 hypertensive patients (134 patients with primary aldosteronism). ROC curves showed comparable areas under the curves of both methods (95% CI: -0.029 to 0.183; p=0.186). Bland-Altman analysis further supported the agreement between ARR and PUKC/BMI ratio. CONCLUSIONS We found that the screening power of PUKC/BMI was as good as that of conventional ARR. With the quick and extensive availability of the PUKC/BMI method and its equivalence to ARR, this screening strategy would be a good first-line tool for massive community-based primary aldosteronism surveys.

High Risk of Herpes Zoster among Patients with Advance Acute Kidney Injury – A Population-Based Study

The risk for herpes zoster (HZ) in acute kidney injury (AKI) survivors was never explored. We identified 2,387 adults in the Taiwan National Health Insurance Research Database who recovered from dialysis-requiring AKI and matched them with non-recovery and non-AKI patients by propensity score. During a mean follow-up of 2.7 years, the incidences of HZ were 6.9, 8.2 and 4.8 episodes per 1,000 person-years in AKI-non-recovery, AKI-recovery and non-AKI group, respectively. The recovery group was more likely to develop herpes zoster than those without acute kidney injury [incidence-rate ratios 1.71, 95% confidence interval 1.16–2.52; p = 0.007]. Patients without acute kidney injury were less likely to develop herpes zoster than those AKI, recovered from dialysis or not (hazard ratio HR 0.66, 95% CI 0.46–0.95). Dialysis-requiring acute kidney injury poses a long-term risk of herpes zoster after hospital discharge. Even patients who have recovered from dialysis still carry a significantly higher risk of developing herpes zoster.

Hypokalemic paralysis: the interplay between primary aldosteronism and hyperthyroidism

Chin-Chi Kuo, Wei-Shun Yang, Vin-Cent Wu, Ching-Wei Tsai, WeiJie Wang and Kwan-Dun Wu TAIPAI, Taiwan Primary Aldosteronism Investigation Study Group, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Department of Internal Medicine, Tao-Yuan General Hospital, Taiwan, Department of Internal Medicine, China Medical University Hospital Taipei Branch, Taipei, Taiwan

Remote organ failure in acute kidney injury

Despite supportive care with renal replacement therapy, acute kidney injury (AKI) remains linked with increased short and long-term mortality, not just because of renal failure but also because of accompanying remote organ dysfunction. Increasing evidence from animal studies suggests that numerous factors contribute both to the development of AKI and the impairment of various vital organs, including pro-inflammatory cytokine expression, leukocyte infiltration, vascular permeability changes, ion channel derangement, oxidative stress, and cell apoptosis. Human studies have reported that AKI with concomitant multi-organ dysfunction is associated with a high death rate. We propose that persistent organ dysfunction after AKI can be considered in relation to three proposed mechanisms (1) classical uremic stress and its associated sequelae (2) systemic inflammation as a consequence of kidney injury (3) treatment-related effects. Using this framework, we discuss the known pathways through which AKI can affect the function of a number of remote organs. We review the short- and long-term clinical impact of AKI on other organ systems and potential mechanisms through which AKI may affect remote organ systems. Further elucidating the effects of AKI on remote organ function may lead to new therapeutic strategies to improve outcomes after AKI.