Triamterene Enhances the Blood Pressure Lowering Effect of Hydrochlorothiazide in Patients with Hypertension.

BACKGROUND: Triamterene, because of its potassium-sparing properties, is frequently used in combination with hydrochlorothiazide (HCTZ) to treat patients with hypertension. By inhibiting the epithelial sodium channel (ENaC) in the cortical collecting duct, triamterene reduces potassium secretion, thus reducing the risk of hypokalemia. Whether triamterene has an independent effect on blood pressure (BP) has not been well studied. OBJECTIVE: To determine if triamterene provides an effect to further lower BP in patients treated with HCTZ. DESIGN: We conducted an observational study using electronic medical record data from the Indiana Network for Patient Care. Participants were 17,291 patients with the diagnosis of hypertension between 2004 and 2012. MAIN MEASURES: BP was the primary outcome. We compared the BP between patients who were taking HCTZ, with and without triamterene, either alone or in combination with other antihypertensive medications, by using a propensity score analysis. For each medication combination, we estimated the propensity score (i.e., probability) of a patient receiving triamterene using a logistic regression model. Patients with similar propensity scores were stratified into subclasses and BP was compared between those taking triamterene or not within each subclass; the effect of triamterene was then assessed by combining BP differences estimated from all subclasses. KEY RESULTS: The mean systolic BP in the triamterene + HCTZ group was 3.8 mmHg lower than in the HCTZ only group (p < 0.0001); systolic BP was similarly lower for patients taking triamterene with other medication combinations. Systolic BP reduction was consistently observed for different medication combinations. The range of systolic BP reduction was between 1 and 4 mm Hg, depending on the concurrently used medications. CONCLUSIONS: In the present study, triamterene was found to enhance the effect of HCTZ to lower BP. In addition to its potassium-sparing action, triamterene's ability to lower BP should also be considered.

Gadolinium-induced nephrogenic systemic fibrosis.

Nephrogenic systemic fibrosis is a new disease whose incidence has peaked and receded over the past decade. It occurs in the presence of significant renal impairment, either acute or chronic (MDRD creatinine clearance of <30 mL/min/1.73 m(2)), and is associated with the administration of gadolinium-based contrast (GBC). Since 2006, the incidence of this disease has decreased markedly in patients with renal impairment, mainly owing to protocols that have not administered GBC to patients with creatinine clearances of less than 30 mL/min/1.73 m(2), and in some cases with the use of less toxic and lower doses of GBC. The purpose of this article is to review the current status of GBC use for imaging in patients with kidney disease.

Challenges of treating a 466-kilogram man with acute kidney injury.

Caring for super obese patients (body mass index > 50 kg/m(2)) presents a number of complex and unique clinical challenges, particularly when acute kidney injury is present. We describe our experience treating the heaviest individual with acute kidney injury requiring renal replacement therapy reported to date. A 24-year-old black man was admitted to our hospital with fever, vomiting, progressive weakness, shortness of breath, and hemoptysis. Admission weight was 1,024 lbs (466 kg), height was 6 ft 4 in (1.9 m), and body mass index was 125 kg/m(2). During hospitalization, the patient experienced oligoanuric acute kidney injury and required initiation of continuous and subsequently intermittent renal replacement therapy. This clinical scenario identifies the many challenges involved in caring for super obese patients with acute kidney injury and may be a harbinger of what awaits the nephrology community in the obesity pandemic era.

Tumor lysis syndrome associated with reduced immunosuppression in a lung transplant recipient.

Tumor lysis syndrome usually occurs after Initiation of chemotherapy or radiation therapy in cancer patients with a moderate to high tumor burden. To our knowledge, the occurrence of this syndrome after discontinuation or reduction of an immunosuppressive regimen has not been reported in the literature. We describe a patient who had undergone lung transplantation and who was receiving immunosuppression and experienced an episode of acute pancreatitis. During the course of the work-up, the patient was found to have a B-cell lymphoma (posttransplantation lymphoproliferative disease). His tacrolimus dosage was decreased, and azathioprine was discontinued. The patient subsequently developed tumor lysis syndrome. Other than the decrease in immunosuppression, we found no other factor that could have accounted for this syndrome.

Elevated serum creatinine and a normal urinalysis: a short differential diagnosis in the etiology of renal failure.

OBJECTIVE: The diagnosis of renal failure with a normal urinalysis represents a short differential diagnosis that has not been characterized in the literature. This study was designed to identify the specific disease states that encompass this interesting renal condition. MATERIAL: The Regenstrief database, which is an electronic medical record containing inpatient laboratory and other clinical data for patients admitted to Wishard Memorial Hospital, was utilized to provide data for this study. METHODS: The database was culled to provide data for hospitalized patients admitted between March 1, 1992, and March 1, 2001, with the concurrent findings of a serum creatinine greater than or equal to 2 mg/dL, a normal urinalysis, and diagnoses of obstructive uropathy, multiple myeloma, prerenal azotemia, hypertensive nephrosclerosis, interstitial nephritis, renal vascular disease, hypokalemic nephropathy, and hypercalcemia, as identified by their corresponding ICD-9 codes. RESULTS: A search of the Regenstrief database yielded a total of 190,343 patient admissions. There were 515 patient admissions with renal failure and a concurrent normal urinalysis. The largest specific diagnostic categories within this group were hypertension and prerenal azotemia. CONCLUSIONS: An elevated serum creatinine and normal urinalysis present a short differential for the etiologies of renal failure and include such entities as hypertensive nephrosclerosis, prerenal azotemia, obstructive nephropathy, interstitial nephritis, renal vascular disease, and various electrolyte abnormalities. An awareness of these specific disease states may lead to an earlier diagnosis and more effective treatment of renal failure.

Prevalence of calcidiol deficiency in CKD: a cross-sectional study across latitudes in the United States.

BACKGROUND: Recent Kidney Disease Outcomes Quality Initiative guidelines have raised concerns of 25-hydroxyvitamin D, or calcidiol, insufficiency and deficiency in patients with chronic kidney disease (CKD) not yet on dialysis therapy; however, no cross-sectional study across latitudes has been performed to support this assertion. METHODS: Baseline screening data from a prospective study were used to determine calcidiol levels in subjects with moderate to severe CKD not yet on dialysis therapy from 12 geographically diverse regions of the United States. Calcidiol deficiency is defined as levels less than 10 ng/mL (< 25 nmol/L), and insufficiency, as levels of 10 to 30 ng/mL (25 to 75 nmol/L). RESULTS: Two hundred one subjects with a mean age 65 +/- 13 years and calculated glomerular filtration rate (GFR) of 27 +/- 11 mL/min (0.45 mL/s) were evaluated. Overall mean calcidiol level was 19.4 +/- 13.6 ng/mL (48 +/- 34 nmol/L), with a range of 0 to 65 ng/mL (0 to 162 nmol/L). Only 29% and 17% of subjects with moderate and severe CKD had sufficient levels, respectively. Mean calcidiol levels were less than sufficient levels in all geographic locations tested. Multivariate analysis found log calcidiol level correlated with calcium level (P = 0.016), log calcitriol level (P = 0.024), sex (P = 0.041), geographic location (P = 0.045), and inverse intact parathyroid hormone level (P = 0.013), but not calculated GFR or phosphorous level. Calcidiol levels changed modestly in 18 patients who had calcidiol levels measured in winter and late summer after confirmed exposure to sunlight, with mean calcidiol levels of 17.9 +/- 11.7 to 21.2 +/- 10.0 ng/mL (45 +/- 29 to 53 +/- 25 nmol/L; P = 0.015). CONCLUSION: This cross-sectional cohort study found a high prevalence of calcidiol deficiency and insufficiency in patients with moderate and severe CKD not on dialysis therapy regardless of geographic location.

Ethylene glycol intoxication: case report and pharmacokinetic perspectives.

A 42-year-old man was brought to the emergency department with ethylene glycol intoxication. He was hemodynamically stable and had normal renal function. His serum ethylene glycol concentration was 284 mg/dl approximately 1 hour after ethylene glycol consumption. The patient was treated with fomepizole and forced diuresis. Elimination of ethylene glycol in this patient followed first-order pharmacokinetics. Elimination pharmacokinetics in this patient were compared with that in a patient who received fomepizole and hemodialysis. Fomepizole monotherapy can be given in patients without renal failure or metabolic acidosis even with serum ethylene glycol concentrations greater than 50 mg/dl. However, cost estimates based on this case suggest that if the patient is treated adequately with a single hemodialysis session and 24-hour hospitalization, then fomepizole monotherapy may be more expensive than the combination regimen of fomepizole and hemodialysis.