Kao-Lang Liu

Klebsiella pneumoniae Genotype K1: An Emerging Pathogen That Causes Septic Ocular or Central Nervous System Complications from Pyogenic Liver Abscess

BACKGROUND Since 1986, researchers have noted a syndrome of Klebsiella pneumoniae pyogenic liver abscess that is complicated by endophthalmitis or central nervous system infections. There are limited data regarding the role of bacterial genotype in the pathogenesis of this syndrome. METHODS We conducted a retrospective cohort study involving 177 cases of K. pneumoniae pyogenic liver abscess treated during 1997-2005 at a tertiary university hospital in Taiwan. We performed bacterial cps genotyping by polymerase chain reaction detection of serotype-specific alleles at wzy and wzx loci and used an in vitro serum assay to evaluate the virulence of bacterial strains. RESULTS Septic ocular or central nervous system complications developed in 23 patients (13%). Logistic regression analysis showed that genotype K1 was the only significant risk factor (adjusted odds ratio, 4.8; 95% confidence interval, 1.5-15.7, P=.009). The serum resistance assay indicated that, on average, K1 strains (n=100) were significantly more virulent than were strains of K2 (n=36), K20/K5/K54 (n=21), or other genotypes (n=20) (P<.001 for each comparison). In addition to the serotype-specific cps region, the genomic background of K1 strains also differed significantly from that of non-K1 strains (20-kb kfu/PTS region, 97/100 vs. 13/77; P<.001). Of the 19 cases in which genotype K1 strains caused complications, 8 patients (42%) did not have identifiable underlying medical diseases. CONCLUSIONS K. pneumoniae genotype K1 is an emerging pathogen capable of causing catastrophic septic ocular or central nervous system complications from pyogenic liver abscess independent of underlying diseases in the host.

131I-6β-Iodomethyl-19-Norcholesterol SPECT/CT for Primary Aldosteronism Patients with Inconclusive Adrenal Venous Sampling and CT Results

The 2 main causes of primary aldosteronism (PA) are aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH). Dexamethasone-suppression 131I-6β-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy can assess the functioning of the adrenal cortex. This study evaluated the diagnostic usefulness of NP-59 SPECT/CT in differentiating APA from IAH and in predicting postadrenalectomy clinical outcome for PA patients who had inconclusive adrenal venous sampling (AVS) and CT results. Methods: We retrospectively reviewed the 31 adrenal lesions of 27 patients (age range, 33–71 y; mean age ± SD, 50.4 ± 10.9 y) who had been clinically confirmed (by saline infusion and captopril tests) to have PA, had inconclusive CT and AVS test results, and had undergone NP-59 imaging before adrenalectomy. The accuracy of NP-59 imaging was determined by comparison with histopathologic findings. Results: NP-59 SPECT/CT gave us 18 true-positive, 3 false-positive, 6 true-negative, and 4 false-negative results. Compared with planar imaging, SPECT/CT significantly improved diagnostic accuracy and prognostic predicting ability (P = 0.0390 and P = 0.0141, respectively). The NP-59 results were negative for 7 of the 23 patients with unilateral adrenal lesions, and none of these 7 patients had shown postsurgical clinical improvement. Conclusion: NP-59 SPECT/CT is an effective imaging tool for differentiating APA from IAH in PA patients whose CT and AVS results are inconclusive. Our results suggest that patients with presurgically negative NP-59 results should be treated medically and that noninvasive NP-59 SPECT/CT may be suited for use as the first lateralization modality after CT in patients with clinically confirmed PA.

Association of Kidney Function With Residual Hypertension After Treatment of Aldosterone-Producing Adenoma

BACKGROUND Autonomous secretion of aldosterone in patients with primary aldosteronism increases glomerular filtration rate and causes kidney damage. The influence of a mild decrease in kidney function on residual hypertension after adrenalectomy is unexplored. STUDY DESIGN Nonconcurrent prospective study. SETTING & PARTICIPANTS The study was based on the Taiwan Primary Aldosteronism Investigation (TAIPAI) database. 150 patients (61 men; overall mean age, 47.2 +/- 11.6 years) with a diagnosis of aldosterone-producing adenoma had undergone unilateral adrenalectomy at National Taiwan University Hospital from July 1999 to January 2007. PREDICTOR Presurgery estimated glomerular filtration rate (eGFR). OUTCOMES & MEASUREMENTS Residual hypertension after adrenalectomy, defined either as less than 75% of recorded blood pressure measurements with systolic blood pressure less than 140 mm Hg and diastolic blood pressure less than 90 mm Hg or requiring antihypertensive medications during the first year after surgery. RESULTS Before surgery, 27 (18%), 72 (48%), and 51 (34%) patients had moderately to severely decreased (<60 mL/min/1.73 m(2)), mildly decreased (60 <or= eGFR < 90 mL/min/1.73 m(2)), or nondecreased eGFR (>or=90 mL/min/1.73 m(2)), respectively. After surgery, 16 (59.3%), 29 (40.3%), and 10 (19.3%) patients in each category had postsurgery residual hypertension. Compared with patients without decreased eGFR before surgery, adjusted odds ratios for postsurgery residual hypertension were 2.7 (95% confidence interval, 1.03 to 7.0; P = 0.04) and 2.8 (95% confidence interval, 1.05 to 9.3) for mildly and moderately to severely decreased eGFR, respectively. LIMITATIONS Arbitrary definition for residual hypertension. CONCLUSIONS Two-thirds of patients with aldosterone-producing adenoma were cured of hypertension by means of unilateral adrenalectomy. Kidney function impairment, even mild, appears to be associated with a high incidence of postsurgery residual hypertension.

Kidney impairment in primary aldosteronism

BACKGROUND Kidney impairment is noted in primary aldosteronism (PA), and probably initiated by glomerular hyperfiltration. METHODS A prospectively defined survey was conducted on 602 patients who were suspected of PA in the multiple-center Taiwan Primary Aldosteronism Investigation (TAIPAI) database. Estimated glomerular filtration rate (eGFR) was calculated and followed up at 1 yr after treatment. RESULTS The diagnosis of PA was confirmed in 330 patients. Among them 17% of these patients had kidney impairment (eGFR<60 ml/min/1.73 m²). Patients with PA had a higher prevalence of estimated hyperfiltration than those with essential hypertension (EH) (14.5% vs. 7.0%, p=0.005). The eGFR independently predicted PA (OR, 1.017) in the propensity-adjusted multivariate logistic model. In PA, plasma renin activity and lower serum potassium (p=0.018) was correlated with kidney impairment (p=0.001), while this relationship was not significant in patients with EH. Either unilateral adrenalectomy or treatment of spironolactone for PA patients caused a decrease of eGFR (p<0.001). Pre-operative hypokalemia (p=0.013) and the long latency of hypertension (p=0.016) could enhance the significant decrease of eGFR after adrenalectomy. CONCLUSIONS Patients with aldosteronism had relative estimated hyperfiltration than patients with EH. Calculation of eGFR may increase the specificity in identifying patients with PA. Our findings demonstrate the correlation of serum potassium and renin with estimated hyperfiltration in PA and their relationship to kidney damage. These results provide a high priority for future renal protective strategies and methods for the early diagnosis and prompt treatment of PA.

Renal Perfusion 3-T MR Imaging: A Comparative Study of Arterial Spin Labeling and Dynamic Contrast-enhanced Techniques

PURPOSE To investigate the feasibility of and correlation between arterial spin-labeling (ASL) and dynamic contrast material-enhanced (DCE) 3-T magnetic resonance (MR) imaging in the measurement of renal blood flow (RBF). MATERIALS AND METHODS The review board approved this study. Nineteen healthy volunteers (seven women, 12 men; age range, 25-68 years) were recruited, and each provided written informed consent. MR imaging was performed with a 3-T whole-body system. Each subject underwent back-to-back ASL and DCE MR imaging. Ten runs of ASL imaging were performed by using the pseudocontinuous tagging scheme, and each run required an 18-second breath hold. For DCE imaging, a gadopentetate dimeglumine bolus (0.0125 mmol per kilogram of body weight) was administrated intravenously in all subjects except two; in the latter subjects, a 0.025 mmol/kg gadopentetate dimeglumine bolus was administered to evaluate the T1 saturation effect. RBF was quantified with both techniques and in both the cortex and the medulla. Agreement was evaluated for RBF measurements obtained with ASL imaging and those obtained with DCE imaging by using correlation analysis. RESULTS RBF was apparently overestimated with 0.025 mmol/kg gadopentetate dimeglumine, which is a concentration that is commonly adopted for 1.5-T DCE. RBF was 227 mL/100 mL/min ± 30 (standard deviation) in the cortex and 101 mL/100 mL/min ± 21 in the medulla, as measured with ASL imaging, and 272 mL/100 mL/min ± 60 in the cortex and 122 mL/100 mL/min ± 30 in the medulla, as measured with DCE imaging. In the cortex, measurements obtained with ASL and DCE imaging exhibited a linear correlation (r = 0.66; statistical power, 0.8 at the 5% significance level) and fair agreement (intraclass correlation coefficient, 0.41). CONCLUSION ASL and DCE 3-T MR imaging are feasible in the quantification of cortical renal perfusion, yielding measurements that are correlated but not entirely comparable. Intermodality differences have yet to be solved.

Bilateral aldosterone-producing adenomas: differentiation from bilateral adrenal hyperplasia

BACKGROUND Primary aldosteronism (PA) is a common curable disease of secondary hypertension. Most such patients have either idiopathic bilateral adrenal hyperplasia (BAH) or unilateral aldosterone-producing adenoma (APA). Bilateral APAs are reportedly extremely rare. AIM To compare the distinctive characteristics, clinical course, and outcomes of bilateral APA vs. BAH. DESIGN Retrospective record review. METHODS From July 1994 to Jan 2007, 190 patients diagnosed with PA underwent surgical intervention at our hospital. Bilateral APA was diagnosed in 7/164 patients with histologically-proven APA. Twenty-one patients diagnosed as BAH, and 21 randomly selected of unilateral APA patients, matched by age and sex served as controls. RESULTS Patients with bilateral APA had similar blood pressure, arterial blood gas analysis, spot urinary potassium to creatinine ratio and clinical symptoms to those with BAH, but lower serum potassium levels (p = 0.027), lower plasma renin activity (p = 0.037), and higher plasma aldosterone concentrations (p = 0.029). Aldosterone-renin ratio (ARR) after administration of 50 mg captopril was higher in bilateral APA than in BAH patients (p = 0.023), but not different between unilateral APA and BAH (p = 0.218). A cut-off of ARR >100 ng/dl per ng/ml/h and plasma aldosterone >20 ng/dl after captopril significantly differentiated bilateral APA from BAH. Bilateral subtotal adrenalectomy normalized blood pressure and biochemistry in all patients with bilateral APA. DISCUSSION Bilateral APA, presenting simultaneously or sequentially, may not be a rare disease, accounting for 4.3% of APA in this sample. The clinical presentations of bilateral functional adenoma are not different from BAH, but patients with low serum potassium and ARR >100 after captopril should be carefully evaluated for bilateral adenoma.

Primary Aldosteronism: Diagnostic Accuracy of the Losartan and Captopril Tests

BACKGROUND To assess whether angiotensin-II receptor blockers (ARBs) offer any additional advantage in confirming the diagnosis of primary aldosteronism (PA) and their use in the differentiation of PA subtypes. METHODS A prospective, cohort, head-to-head study was conducted between July 2003 and July 2006. A total of 135 patients received captopril and losartan tests to confirm the diagnosis of PA in the TAIPAI (Taiwan Primary Aldosteronism Investigation) intervention. RESULTS In total, 71 patients were diagnosed with PA. The area under the receiver-operating characteristic (ROC) curve of the postcaptopril plasma aldosterone concentration (PAC) was significantly less than that of the postlosartan PAC (0.744 vs. 0.829, P = 0.038). Using an aldosterone-renin ratio (ARR, ng/dl per ng/ml/h) >35 with a PAC >10 ng/dl, the specificity was 89.1% vs. 93.8% and the sensitivity was 66.2% vs. 84.5 % for the captopril test vs. the losartan test, respectively. With respect to the losartan test, the accuracy was 88.9%, the agreement was good (k = 0.778), and there was no disagreement with the McNemar test (P = 0.118). Losartan had the advantage of a better negative predictive value to exclude PA when patients were referred with a serum potassium (SK) level <3.8 mmol/l. When a postlosartan ARR >60 was the cutoff value, the positive predictive value was 82% with a negative predictive value of 57% in distinguishing aldosterone-producing adenomas (APAs) from idiopathic hyperaldosteronism (IHA). CONCLUSIONS The postlosartan ARR and PAC were shown to have better accuracy for the diagnosis of PA than the captopril test. With a postlosartan ARR >60, APAs can be adequately differentiated from IHA.

Primary aldosteronism: changes in cystatin C-based kidney filtration, proteinuria, and renal duplex indices with treatment.

Objectives To obtain information about the effect of prolonged aldosterone excess on kidney function. Methods We determined kidney function changes defined by cystatin C-based estimations of glomerular filtration rate (CysC-GFR). Pretreatment proteinuria and intrarenal Doppler velocimetric indices in primary aldosteronism were examined and followed after adrenalectomy or spironolactone treatment. Results This prospective, multicenter study included 130 primary aldosteronism patients (56 men; age, 49.9 ± 13.4 years: 100 with adenoma and 30 with idiopathic hyperaldosteronism) and 73 essential hypertension patients (36 men; age, 51.4 ± 14.8 years) as controls. Patients with primary aldosteronism had higher CysC-GFR (P < 0.05) and heavier proteinuria (0.042) than those with essential hypertension. With primary aldosteronism, a higher aldosterone–renin ratio (odds ratio, OR = 7.85, P = 0.008) was independently related to pretreatment CysC-GFR. The factors related to pretreatment proteinuria included CysC-GFR (OR, −0.006, P = 0.001), plasma aldosterone concentration (OR, 0.004, P = 0.002), and duration of hypertension (OR, 0.016, P = 0.032). Duration of hypertension was also independently correlated with the pretreatment resistive index among primary aldosteronism patients (OR, 0.004, P = 0.035). CysC-GFR (all, P < 0.05), proteinuria (P < 0.001), and resistive index (P < 0.001) decreased 1 year after adrenalectomy but not with spironolactone treatment. Conclusion Our data suggest that prolonged hyperaldosteronism will cause relative kidney hyperfiltration and reversible intrarenal vascular structural changes, which disguise the consequent renal injury, including declining GFR and proteinuria. Adrenalectomy and spironolactone treatment exert different clinical impacts toward kidney damage even with a similar blood pressure-lowering effect.

Reversal of myocardial fibrosis in patients with unilateral hyperaldosteronism receiving adrenalectomy

BACKGROUND Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with more prominent left ventricular hypertrophy and increased myocardial fibrosis. Unilateral hyperaldosteronism can be cured by adrenalectomy. However, the reversibility of cardiac fibrosis is still unclear. METHODS We analyzed 11 patients prospectively with unilateral hyperaldosteronism (including 10 aldosterone-producing adenomas and 1 unilateral nodular hyperplasia) who received adrenalectomy from October 2006 to October 2007, and 17 patients with essential hypertension (EH) were enrolled as the control group. Echocardiography included ultrasonic tissue characterization by cyclic variation of integrated backscatter; it was performed in both groups and 1 year after operation in the unilateral hyperaldosteronism group. RESULTS Patients with unilateral hyperaldosteronism had significantly higher diastolic blood pressure, higher plasma aldosterone concentration, lower serum potassium level, and lower plasma renin activity than patients with EH. In echocardiography, patients with unilateral hyperaldosteronism had thicker interventricular septal thickness, left ventricular posterior wall thickness, and higher left ventricular mass index than EH patients. Patients with unilateral hyperaldosteronism had significant lower cyclic variation of integrated backscatter than EH patients (7.1 ± 2.1 vs 8.7 ± 1.5 dB, P = .037). After analyzing the correlation of cyclic variation of integrated backscatter with clinical parameters for all participants, only log-transformed plasma renin activity was correlated significantly with cyclic variation of integrated backscatter. One year after adrenalectomy, interventricular septal thickness, left ventricular posterior wall thickness, and left ventricular mass index decreased significantly. In addition, cyclic variation of integrated backscatter increased significantly after adrenalectomy (7.1 ± 2.1 to 8.5 ± 1.5 dB, P = .02). CONCLUSION Adrenalectomy not only reversed left ventricular geometry but also altered myocardial texture in patients with unilateral hyperaldosteronism. This finding implies that increases in collagen content in the myocardium of patients with unilateral hyperaldosteronism might be reversed by adrenalectomy.

N-butyl Cyanoacrylate Embolization as the Primary Treatment of Acute Hemodynamically Unstable Lower Gastrointestinal Hemorrhage

PURPOSE To evaluate N-butyl cyanoacrylate (NBCA) embolization as the primary treatment for patients with severe and acute hemodynamically unstable lower gastrointestinal bleeding. MATERIALS AND METHODS Twenty-seven patients with acute, unstable hemodynamics caused by lower gastrointestinal bleeding underwent therapeutic NBCA microcatheter embolization over a period of 27 months. The inclusion criteria were hematochezia or melena and hypotension refractory to conservative treatment and requiring blood transfusion. Bleeding was localized to the rectum, colon, or small intestine in all nine such cases. Fifteen patients had severe underlying comorbidities, including sepsis, respiratory failure, malignancy, or renal failure. RESULTS The procedure was technically successful in all patients. Twenty-six patients were treated solely with NBCA, and one required microcoil embolization. Embolization was performed at the level of the arteria recta or as close as possible to the point of bleeding. Immediate hemostasis occurred in all cases. Four patients experienced repeat hemorrhage, one of whom died. The other three were treated successfully with repeat NBCA embolization. None of the surviving patients had evidence of bowel ischemia. In addition, none of the patients with severe underlying disease died during the follow-up period (range, 3 mo to 2 y). CONCLUSIONS The present findings suggest that NBCA embolization may be a safe alternative treatment for the management of lower gastrointestinal bleeding. Further studies are warranted to confirm the findings.