Prevalence of Proteinuria and Albuminuria in an Obese Population and Associated Risk Factors.

Obesity has been increasingly recognized as a risk factor for kidney disease and both proteinuria and microalbuminuria have been associated with obesity. The actual prevalence of microalbuminuria and proteinuria in obese patients in the United States (US) has not been clearly described in the literature. Furthermore, obesity is associated with risk factors of kidney disease, such as diabetes and hypertension (HTN), and the prevalence of proteinuria and albuminuria excluding these risk factors is uncertain. In this study, we collected urine albumin/creatinine and urine protein/creatinine ratios on obese patients undergoing bariatric surgery to determine the prevalence of albuminuria and proteinuria in obese patients with and without associated diabetes and HTN. The study included 218 obese patients undergoing bariatric surgery at a New York City hospital. The mean age was 42.1 ± 11.3 years. The mean body mass index (BMI) was 43.9 ± 8.1. Diabetes (DM) was present in 25%. HTN was present in 47%. The prevalence of proteinuria and albuminuria was 21% (95% CI: 15.8-27.1%) and 19.7% (95% CI: 14.2-26.2%) respectively. Among those without DM but who had HTN, 22.6% (95% CI: 12.9-35) had proteinuria and 17% (95% CI 8.4-30.9) had albuminuria. Of patients with neither DM nor HTN, 13.3% (95% CI: 7.3-21.6) and 11% (95% CI: 5-17%) had proteinuria and albuminuria, respectively. Diabetics had a significantly higher prevalence of proteinuria and albuminuria than the non-diabetic groups. The non-diabetic groups did not differ significantly from each other in terms of prevalence of proteinuria and albuminuria. The BMI for diabetics did not differ from non-diabetics. On multivariate analysis, only the presence of diabetes was associated with proteinuria and albuminuria. BMI, age, and HTN were not predictive. In conclusion, we found a relatively high prevalence of microalbuminuria and proteinuria in an urban, US, obese population undergoing bariatric surgery. When diabetics were excluded, there was a lower prevalence. Even patients who had neither diabetes nor HTN, still, however, had much greater amounts than seen in the general US population, likely reflecting an adverse effect of obesity itself on renal physiology.

Use of lung ultrasonography to determine the accuracy of clinically estimated dry weight in chronic hemodialysis patients.

PURPOSE: The use of lung ultrasound (LUS) to identify extravascular lung water has received increasing acceptance. Sonographic B-lines, discrete vertical lines that originate from the pleura, represent pulmonary edema and are correlated with the accumulation of fluid. The goal of this study was to evaluate the utility of LUS to determine the accuracy of prescribed dry weight (DW) in chronic hemodialysis (HD) patients and to ascertain the adequacy of fluid removal. METHODS: LUS was scheduled to be performed pre- and post-HD in 20 patients. The HD prescription and DW challenge were done independent of the results of the LUS. The presence of B-lines was tabulated and compared to the intradialytic ultrafiltration parameters. RESULTS: Of the 20 patients, 3 did not exhibit B-lines at the first dialysis session. In regard to the other 17 patients, B-lines disappeared in 7 patients at the end of the HD session (mean B-lines 4.2-0). One patient was 0.3 kg away from the prescribed dry weight, but the 6 patients were a mean of 1.7 kg below DW. Of the remaining 10 patients, eight decreased but did not eliminate the B-lines (mean B-lines 15.5-3.8) and were a mean of 3.8 kg below DW post-HD. Two patients who exhibited more cardiac insufficiency than initially recognized could not reach DW or eliminate the B-lines. Eight patients who had residual B-lines at the end of the first HD session had their DW re-estimated and had a second session. Two were able to eliminate the B-lines (mean 2.5-0) and reached a mean of 1.2 kg below DW. Six did not eliminate the B-lines (mean 11.5-4.2) but were able to reach a mean of 0.6 kg below DW. Correlation analysis showed a statistically significant correlation (P < 0.05) between the intradialytic percent change in B-lines and the percent change in total body weight (r = 0.40) and ultrafiltration rate (r = 0.33). Seven of 10 patients with clear chest X-rays pre-HD exhibited B-lines. CONCLUSIONS: This study supports the hypothesis that reduction in B-lines during HD can provide accurate information regarding changes in pulmonary fluid content. Further, LUS is a valuable diagnostic tool for recognizing both the adequacy of fluid removal and the occurrence of error in the estimation of dry weight by usual clinical parameters.

Oral vitamin C supplementation reduces erythropoietin requirement in hemodialysis patients with functional iron deficiency.

PURPOSE: Functional iron deficiency (FID) is a major cause of persistent anemia in dialysis patients and also contributes to a suboptimal response to erythropoietin (Epo) administration. Vitamin C acts as an enzyme cofactor and enhances mobilization of the ferrous form of iron to transferrin thus increasing its bioavailability. High-dose intravenous vitamin C has been shown to decrease the Epo requirement and improve hemoglobin levels in previous studies. This study assessed the effect of low-dose oral vitamin C on possible reduction in Epo dose requirements in stable hemodialysis patients with FID. METHODS: This prospective study included 22 stable hemodialysis patients with FID defined as transferrin saturation (T sat) <30 % and ferritin levels of >100 mcg/L with Epo requirement of ≥4000 U/HD session. Patients received oral vitamin C 250 mg daily for 3 months. Hemoglobin, iron and T sat levels were recorded monthly. No one received iron supplementation during the study period. RESULTS: There was a significant reduction in median Epo dose requirement in the 15 patients who completed the study, from 203.1 U/kg/week (95 % CI 188.4-270.6) to 172.8 U/kg/week (95 % CI 160.2-214.8), (P = 0.01). In the seven responders, there was 33 % reduction in Epo dose from their baseline. Despite adjustment of Epo dose, the mean hemoglobin level was significantly increased from 10.1 ± 0.6 to 10.7 ± 0.6 mg/dL (P = 0.03). No adverse effects of oral vitamin C were observed. CONCLUSION: Daily low-dose oral vitamin C supplementation reduced Epo dose requirements in hemodialysis patients with FID. Limitations of this study include a small sample size and the lack of measurements of vitamin C and oxalate levels. Despite concerns regarding oral vitamin C absorption in dialysis patients, this study indicates vitamin C was well tolerated by all participants without reported adverse effect.

Presence of Anti-Glomerular Basement Membrane Antibodies and Myeloperoxidase Anti-Neutrophilic Cytoplasmic Antibodies in a Case of Rapidly Progressive Glomerulonephritis.

A 69-year-old male had initially presented with low-grade proteinuria, microhematuria, and a positive myeloperoxidase anti-neutrophilic antibody (ANCA). He subsequently developed deterioration of kidney function and developed uremic symptoms. Creatinine was 486.2 µmol/L (5.5 mg/dL). Anti-MPO was positive (titer >8 U, normal <0.4). He was clinically diagnosed with rapidly proliferative glomerulonephritis most likely due to ANCA vasculitis. He received three doses of pulse methylprednisolone therapy. Kidney biopsy showed pauci-immune glomerulonephritis. Immunofluorescence was positive for faint linear IgG staining of glomerular basement membrane (GBM). Anti-GBM antibody was positive 2.1 U (normal <1). He was started on high-dose oral steroids; monthly intravenous cyclophosphamide and plasmapheresis were also initiated. His symptoms improved and creatinine is 247.5 µmol/L (2.8 mg/dL). His repeat anti-GBM antibody was negative. This is a rare case of rapidly progressive glomerulonephritis due to dual MPO-ANCA antibodies and anti-GBM antibodies (DAV).

A review of the nonpressor and nonantidiuretic actions of the hormone vasopressin.

The pressor and antidiuretic actions of arginine vasopressin (AVP) have been well documented. This review focuses on the less widely appreciated actions of AVP which also have important physiologic functions and when better understood may provide important insights into common disease states. These actions include effects on pain perception and bone structure as well as important relationships to the varied components of metabolic syndrome. These include effects on blood glucose, lipid levels, and blood pressure. AVP may also play a role in the progression of chronic kidney disease and effect physiologic changes relating to aging, abnormal social behavior, and cognitive function. Important cellular responses including cell proliferation, inflammation, and control of infection and their relationship to AVP are described. Finally, the effects of AVP on hemostasis and the hypothalamic-pituitary-adrenal axis are noted. The goal of this summary of the various actions of AVP is to direct attention to the potential benefits of research in these underemphasized areas of importance.

Mycophenolate mofetil as a steroid-sparing agent in sarcoid-associated renal disease.

Steroids are the mainstay of treatment for renal sarcoidosis. Many patients with sarcoidosis are chronically dependent on steroids and there is limited data on the use of steroid-sparing agents. This is a case of a patient that has remained in remission using mycophenolate mofetil (MMF) as a steroid-sparing agent. The patient is a 56-year-old female with a history of sarcoidosis diagnosed by lymph node biopsy who developed 3 episodes of acute kidney injury (AKI) in the setting of exacerbations of her sarcoidosis, each responding to prednisone treatment. Due to possible lifelong need for prednisone, MMF was started as a steroid-sparing treatment. She tolerated the MMF well and has now been steroidfree for 22 months. There have been only a few case reports about the use of MMF as a steroid-sparing agent in sarcoid-associated renal disease, in which patients could be successfully weaned off steroids. This is the longest reported follow-up of a patient being off steroids while on MMF. It is also notable for the patient having a relapse on the MMF which responded to an increased dose. MMF should be studied further as a potential steroid-sparing agent in the treatment of sarcoid associated renal disease.

Preventing the progression of chronic kidney disease: two case reports and review of the literature.

A variety of therapeutic modalities are available to alter the abnormalities seen in patients with chronic kidney disease (CKD). A comprehensive plan can now be developed to slow the progression of CKD. Two clinical cases of delay in the need for renal replacement therapy are described. This delay was achieved by using recognized recommendations for optimal diabetes therapy (HbA1c target 7 %), goals for blood pressure levels, reduction of proteinuria, and the proper use of ACEI/ARB therapies. Recent recommendations include BP <140/90 mmHg for patients <60 years old and <150/90 mmHg for older patients unless they have CKD or diabetes. Limits on dietary sodium and protein intake and body weight reduction will decrease proteinuria. Proper treatment for elevated serum phosphorous and parathyroid hormone levels is now appreciated as well as the benefits of therapy for dyslipidemias and anemia. Concerns regarding unfavorable outcomes with excess ESA therapy have led to hemoglobin goals in the 10-12 g/dL range. Finally, new therapeutic considerations for the treatment of acidosis and hyperuricemia are presented with data available to suggest that increasing serum bicarbonate to >22 mmol/L is beneficial, while serum uric acid therapeutic goals are still uncertain. Also, two as yet insufficiently understood approaches to altering the course of CKD (FGF-23 level reduction and balancing gut microbiota) are noted.

Characteristics, therapies, and factors influencing outcomes of hospitalized hypernatremic geriatric patients.

PURPOSE: Hypernatremia is a common electrolyte disorder associated with adverse outcomes such as increased length of stay and mortality due to a variety of factors. Our aim was to investigate known factors as well as other variables which we had identified in hospitalized hypernatremic geriatric patients and their relationship to patient outcomes. METHODS: A retrospective chart review of all adult hospitalized patients in a 4-month period with a serum sodium level >150 mmol/L was performed. Factors evaluated included use of a nephrology consultation, certain urine laboratory measures, fluids employed, rate of correction, and patient's level of care setting. Outcome measures included length of stay and mortality. RESULTS: The patient mortality rate was 52 %. Mean age was 79.6 years (n = 33), and mean initial sodium level was 152.6 mmol/L. Plasma and urine osmolality, and urine sodium concentration were checked in less than 25 % of patients. Fifteen of 18 patients in the ICU expired, whereas only 2 of 15 patients not in the ICU expired (p < 0.0004, OR 32.50, CI 95 % (4.68-225.54)). Of the 23 patients (70 %) who had their serum sodium level corrected, 11 were corrected in ≤3 days and 12 in >3 days, but this difference did not affect mortality rate (45 vs. 50 %, p = 0.99). The mortality rate was similar (60 %, p = 0.52) for those whose serum sodium level never corrected suggesting that correction did not influence outcomes. The fluids chosen for therapy of the hypernatremia were appropriate to the patients volume status. Five of 15 patients who received a nephrology consultation survived, while 11 of 18 patients without a nephrology consultation survived (p = 0.12). The mean length of stay was 25.0 ± 23.9 days and no different for those who expired versus those who survived (25.2 ± 21.2 vs. 24.8 ± 25.9 days, p = 0.96). CONCLUSIONS: Hypernatremia is associated with a poor prognosis, and outcomes are still disappointing despite appropriate rates of correction, intensive monitoring, and the involvement of a nephrologist. Strategies directed at avoidance of the development of hypernatremia and attention to concomitant disease may provide significant patient benefit.

Neurofibromatosis type 1-associated hypertension secondary to coarctation of the thoracic aorta.

Neurofibromatosis type 1 (NF-1), also known as von Recklinghausen's disease, is an autosomal dominant genetic disorder. NF-I vasculopathy has been used to describe various vascular malformations associated with NF-1. Secondary hypertension related to NF-1 vasculopathy has been reported because of renal artery stenosis, coarctation of the abdominal aorta and other vascular lesions; however, coarctation of the thoracic aorta has seldom been reported. We report the first case, to our knowledge, of isolated coarctation of thoracic aorta in a pregnant female with NF-1. Healthcare providers caring for patients with NF-1 should be aware of associated vascular complications.

Massive intravascular hemolysis with mechanical rheolytic thrombectomy of a hemodialysis arteriovenous fistula.

A 57-year-old man with chronic kidney disease stage 5 presented for ambulatory evaluation of his arteriovenous fistula. He underwent rheolytic thrombectomy with tissue plasminogen activator infusion, angioplasty, and brachial artery stenting under local sedation. His immediate postoperative course was complicated by hypotension, cardiac dysrhythmias and hyperkalemia requiring emergent hemodialysis, due to severe intravascular hemolysis. This case illustrates that mechanical thrombectomy can cause clinically significant intravascular hemolysis, thus careful postoperative monitoring is recommended.

Troponin I as a prognostic marker of cardiac events in asymptomatic hemodialysis patients using a sensitive troponin I assay.

Elevated troponin T is known to be a prognostic marker for long-term cardiac events and mortality in asymptomatic end-stage renal disease patients. There are conflicting data in this regard with respect to troponin I (TnI). We recently showed a high incidence of elevated TnI levels in asymptomatic hemodialysis (HD) patients using a new generation sensitive TnI assay. The aim of this pilot study was to explore the prognostic value of TnI, as measured with this new assay, as a marker for outcomes in HD patients over a 2-year follow-up period. Fifty-one asymptomatic HD patients were enrolled, and pre-dialysis TnI levels were checked once monthly over 3 consecutive months. Patients were considered to be in the TnI positive group if TnI level on any of the three draws was ≥0.035 ng/ml. All patients were followed for a period of 2 years. The primary end points were acute coronary syndrome, coronary revascularization, sudden death, or cardiac arrest. The secondary end point was all-cause mortality. Elevated TnI levels were found in 51% (26/51) of patients in our cohort. One TnI positive patient was subsequently lost to follow up. There were 6 cardiac events over 2 years, all of which were in the troponin positive group (6/25 or 24%). The presence of a positive TnI at baseline was significantly associated with future cardiac events (p=0.022). A prior history of coronary artery disease (CAD) was also significantly related to future cardiac events (p=0.010). No patient with negative TnI at baseline developed a cardiac event, while 45.5% of those with both a positive TnI and a history of CAD had an event. Fourteen deaths occurred over 2 years, 8 in TnI positive and 6 in the negative group. All-cause mortality was not associated with elevated TnI levels at baseline. We found a significant association between positive TnI and subsequent cardiac events in asymptomatic HD patients followed for 2 years. TnI levels, as measured with a sensitive assay, may be useful in assessing cardiac risk in asymptomatic HD patients. This needs further confirmation in a larger cohort.

Serum and urine responses to the aquaretic agent tolvaptan in hospitalized hyponatremic patients.

Tolvaptan, an oral, selective arginine vasopressin (AVP) V2 receptor antagonist has been approved for the treatment of euvolemic and hypervolemic hyponatremia in the United States. This report summarizes our center's experience with thirteen patients treated for hyponatremia with one 15-mg dose of tolvaptan. The patients had euvolemic or hypervolemic hyponatremia with decreased serum osmolality and serum sodium (SNa) levels less than 129 mEq/L. Eight patients had a diagnosis of the syndrome of inappropriate antidiuretic hormone (SIADH), and five patients had a diagnosis of congestive heart failure (CHF). Results revealed an increase in SNa in all patients from 122.5 ± 4.2 to 128.9 ± 4.1 mEq/L (P < 0.05). The mean increase in SNa of 6.4 mEq/L (range 2-10 mEq/L) 24 h post-tolvaptan was not different in the two groups of patients, but SIADH patients had higher pre and post-tolvaptan SNa levels than CHF patients. Urine osmolalities (UOsm) decreased in all patients, and the patients with SIADH had significantly higher baseline UOsm and a larger decrease in UOsm 12 h post-tolvaptan administration when compared with the CHF patients. AVP levels did not change post-tolvaptan administration. However, the magnitude of increase in SNa levels was inversely related to pretolvaptan AVP levels in the SIADH subgroup (r = -0.7, P = 0.01). Three SIADH patients received small amounts of D5W to attenuate changes in SNa. No significant changes in mean arterial pressure, serum potassium, serum glucose, and blood urea nitrogen or serum creatinine were observed. The data show that tolvaptan is effective for the treatment of hyponatremia and may produce differing responses in disparate patient groups.

Conversion to lanthanum carbonate monotherapy effectively controls serum phosphorus with a reduced tablet burden: a multicenter open-label study.

BACKGROUND: Lanthanum carbonate (FOSRENOL®) is an effective, well-tolerated phosphate binder. The ability of lanthanum to reduce serum phosphorus levels to ≤5.5 mg/dL in patients with end-stage renal disease (ESRD) was assessed in a clinical practice setting. METHODS: A 16-week, phase IV study enrolled 2763 patients at 223 US sites to evaluate the efficacy of lanthanum carbonate in controlling serum phosphorus in patients with ESRD, and patient and physician satisfaction with, and preference for, lanthanum carbonate after conversion from other phosphate-binder medications. Patients received lanthanum carbonate prescriptions from physicians. These prescriptions were filled at local pharmacies rather than obtaining medication at the clinical trial site. Changes from serum phosphorus baseline values were analyzed using paired t tests. Patient and physician preferences for lanthanum carbonate versus previous medications were assessed using binomial proportion tests. Satisfaction was analyzed using the McNemar test. Daily dose, tablet burden, and laboratory values including albumin-adjusted serum calcium, calcium × phosphorus product, and parathyroid hormone levels were secondary endpoints. RESULTS: Serum phosphorus control (≤5.5 mg/dL) was effectively maintained in patients converting to lanthanum carbonate monotherapy; 41.6% of patients had controlled serum phosphate levels at 16 weeks. Patients and physicians expressed markedly higher satisfaction with lanthanum carbonate, and preferred lanthanum carbonate over previous medication. There were significant reductions in daily dose and daily tablet burden after conversion to lanthanum carbonate. CONCLUSIONS: Serum phosphorus levels were effectively maintained in patients converted from other phosphate-binder medications to lanthanum carbonate, with increased satisfaction and reduced tablet burden. TRIAL REGISTRATION: ClinicalTrials.gov: NCT0016012.

Troponin I levels in asymptomatic patients on haemodialysis using a high-sensitivity assay.

BACKGROUND: Troponin I (TnI) is an effective marker for detecting myocardial injury, but the interpretation of levels in the setting of end-stage renal disease (ESRD) is still unclear. TnI levels have been noted to be increased in 5-18% of asymptomatic haemodialysis (HD) patients with standard assays, but newer-generation, high-sensitivity assays have not been examined. In addition, there is limited data on the variability of TnI levels in patients over time as well as the effect of HD on TnI levels. The aim of this study was to prospectively explore the incidence of TnI with a high-sensitivity assay, the variability of TnI levels over time and the effect of HD on levels. METHODS: We enrolled 51 asymptomatic HD patients and checked TnI levels using a high-sensitivity assay. Levels were drawn pre-HD monthly for three consecutive months. As per manufacturer guidelines, levels were considered normal up to 0.034 ng/mL, indeterminate elevation (IE) if between 0.035 and 0.120 ng/mL and consistent with myocardial infarction (MI) if >0.120 ng/mL. In the third month, post-HD TnI was also drawn to determine change with dialysis. RESULTS: At baseline, median TnI level was 0.025 ng/mL (range, 0-0.461 ng/mL). Baseline TnI levels were normal in 63% and elevated (≥0.035 ng/mL) in 37%. Of those with elevations, 79% were in the IE range and 21% in the acute myocardial infarction range. Higher TnI levels at baseline were associated with a history of coronary artery disease, left ventricular hypertrophy, lower cardiac ejection fraction and higher serum phosphate levels. Average incidence of elevated TnI was 41% over the 3 months. Thirty-six patients had stable levels without a change in classification over 3 months. Twelve varied over time. Forty-five (94%) had no change in classification pre- and post-HD. CONCLUSION: Using a new-generation, high-sensitivity assay, over a third of asymptomatic ESRD patients have an elevated TnI. The significance of these low-level elevations is unclear at this time. TnI levels remain stable over a 3-month period in most patients. HD treatment does not appear to affect the TnI level.

Impact of heart failure on the incidence of contrast-induced nephropathy in patients with chronic kidney disease.

We randomized patients with chronic kidney disease (serum creatinine ≥ 1.5 mg/dl or glomerular filtration rate (GFR) <60 ml/min/1.73 m²) in a double-blind fashion to receive saline or sodium bicarbonate prior to and after cardiac or vascular angiography. The primary endpoint was contrast-induced nephropathy (CIN), defined as an increase in serum creatinine by 25% or by 0.5 mg/dl from baseline. Patients with congestive heart failure (CHF), cardiac ejection fraction (EF) <30%, or GFR < 20 ml/min/1.73 m² were excluded. The study was discontinued (after 142 patients were randomized) due to a low incidence of CIN (1.5%). We retrospectively identified all cases of CIN (n = 30) at our institution during the same time period to see if these patients differed from our trial sample. There was no difference in serum creatinine (1.7 ± 0.4 vs. 1.7 ± 0.6 mg/dL), GFR (42.7 ± 9.7 vs. 45.3 ± 3.2 ml/min), incidence of diabetes (51.8% vs. 63.3%), contrast volume (121.7 ± 63.8 vs. 122.7 ± 68.3 ml), ACE inhibitor or angiotensin receptor blocker use (54.0% vs 63.3%), and periprocedure diuretic use (33.1% vs 26.7%). On multivariate analysis, only a cardiac ejection fraction (EF) of less than 40% was significantly associated with CIN (odds ratio, 4.52; 95% confidence interval, 1.30-15.71; P = 0.02). In all, 22/30 patients (73.3%) who developed CIN had at least one or more characteristics that would have excluded their enrollment in our randomized trial including evidence of congestive heart failure (17/30 patients), EF less than 30% (9 patients), age greater than 85 years (2 patients), or advanced renal failure with a baseline GFR of less than 20 cc/min (1 patient). In summary, patients with CKD without evidence of CHF who receive adequate hydration appear to have a very low risk of CIN associated with angiography. A low EF (less than 40%) appeared to be the most significant risk factor for CIN in our population.

Hyponatremia associated with large-bone fracture in elderly patients.

Hyponatremia has been shown to be associated with gait disturbances, decreased mentation, and falls. The study objective was to determine the incidence of hyponatremia in patients who experienced a substantial skeletal fracture (hip/pelvis/femur). During an 18-month period from March 2007 to August 2008 serum sodium levels were evaluated in 364 cases of bone fracture in patients aged 65 years or older and in 364 nonfracture patients aged 65 years and older seen in an urban emergency room setting. The incidence of hyponatremia in patients with fractures was more than double that of nonfracture patients (9.1% and 4.1%, respectively; P = 0.007). The degree of hyponatremia was noted to be mild to moderate. Mean serum sodium of the entire fracture group was 131 +/- 2 mEq/L. In the fracture group the patients were 75.3% female, while females comprised 66.2% of the nonfracture group (P = 0.02). Of fracture patients with hyponatremia, 24.2% were taking antidepressants [3/4 of which were selective serotonin receptor inhibitors (SSRIs)], while none were taking these medications in the nonfracture group. Attention regarding careful follow-up of serum sodium levels in elderly patients seems appropriate.

A case of bovine ketoacidosis in a lactating woman.

A 36 year-old 5 weeks postpartum lactating woman presented to the emergency room with severe nausea and vomiting for 48 hours. The patient was found to be in non-diabetic ketoacidosis with a serum pH 6.9 and a HCO3 of <5mEq/L. This condition rapidly improved with the administration of intravenous dextrose and bicarbonate and with the cessation of breast feeding. The course and pathophysiology of the rarely described phenomenon of bovine ketosis in a human is discussed here.

The effect of withdrawal of ACE inhibitors or angiotensin receptor blockers prior to coronary angiography on the incidence of contrast-induced nephropathy.

BACKGROUND: The effect of continuing or discontinuing chronic angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) therapy prior to coronary angiography on the incidence of contrast-induced nephropathy (CIN) is not clear. We undertook a randomized trial to evaluate the effect of withdrawing ACEIs or ARBs 24 h prior to coronary angiography on the incidence of CIN associated with coronary angiography. METHODS: A total of 220 patients with chronic kidney disease (CKD) stages 3-4 (glomerular filtration rate 15-60 ml/min/1.73 m2) on ACEI or ARB therapy were randomized before angiography to either ACEI/ARB continuation group or discontinuation group. A third group of patients with CKD stages 3-4 but not on angiotensin blockade therapy were also followed. The primary outcome measure was the incidence of CIN defined by a rise in serum creatinine by 25% or 0.5 mg/dl (44 micromol/l) from baseline. RESULTS: There was no statistically significant difference in the incidence of CIN between the three groups (P=0.66). The incidences were 6.2%, 3.7%, and 6.3% for the continuation, discontinuation, and angiotensin blockade naïve group, respectively. There was also no significant difference found between the groups in mean serum creatinine and glomerular filtration rate values at baseline and post contrast administration. CONCLUSION: Withholding ACEIs and ARBs 24 h before coronary angiography does not appear to influence the incidence of CIN in stable patients with CKD stages 3-4.

Observations regarding the use of the aquaretic agent conivaptan for treatment of hyponatremia.

The treatment of hyponatremia, especially euvolemic and hypervolemic hyponatremia, has changed with the development of drugs which function as vasopressin receptor antagonists. These agents increase solute-free water excretion by the kidney resulting in an aquaresis. Conivaptan, a vasopressin receptor antagonist, has recently been approved by the FDA in the United States for use in the therapy of both euvolemic and hypervolemic hyponatremia. This report summarizes one center's experience with ten patients treated with this new drug. The patients had euvolemic hyponatremia with serum sodium levels less than 128 mEq/l. The same protocol was used in all patients with the conivaptan being given as a 20-mg intravenous loading dose followed by a 20-mg continuous 24-h infusion. Review of the data revealed that six of the ten patients had an excellent response to the therapy, with serum sodium increasing by a mean of 8.5+/-0.8 mEq/l (increases ranged from 7 to 12 mEq/l over 24 h). No significant changes in serum potassium levels or mean arterial pressures were noted. Two of the ten patients experienced a decrease in urine osmolality without a significant increase in serum sodium. Two other patients had only slight decreases in urine osmolality, and no significant increase in serum sodium levels. The data reveal that conivaptan is useful in the management of significant hyponatremia. There were no significant untoward effects, with the exception of one patient whose blood pressure decreased during the conivaptan infusion and who responded to cessation of the infusion and saline replacement therapy. This new class of drugs holds great promise for the treatment of dilutional hyponatremic disorders.

Iron deficiency in patients with chronic kidney disease: potential role for intravenous iron therapy independent of erythropoietin.

UNLABELLED: The prevalence of iron deficiency and its contribution to the anemia of end stage renal disease has been extensively studied, but much less is known about the role of iron deficiency in the pathogenesis of the anemia of chronic kidney disease in predialysis patients. All new hemodialysis patients entering a single hemodialysis unit between July 1999 and April 2002 were included in the study. The admission laboratory tests and the Health Care Financing Administration (HCFA) 2728 form were examined to determine the prevalence of erythropoietin use, anemia (Hb<11 g/dl), and iron deficiency (ferritin<100 ng/ml and transferrin saturation %<20%). In a second part of the study, the effect of intravenous iron gluconate replacement in patients with stage III & IV chronic kidney disease was examined. Anemia was present in 68% of all patients starting hemodialysis. Iron deficiency was a common feature occurring in 29% of patients taking erythropoietin (49% of all patients) and 26% of patients without erythropoietin (51% of all patients). Following the administration of intravenous iron gluconate to four patients, there was a significant rise in hemoglobin levels from 10.6+/-0.19 to 11.7+/-g/dl (p=0.02). CONCLUSION: Iron deficiency is common in predialysis patients. Replenishing iron stores in anemic patients with chronic kidney disease significantly increases hemoglobin levels and should be considered as an integral part of the therapy for treating anemia in the predialysis population.