transtubular gradient

Renal tubular acidosis (RTA) is a rare complication of renal involvement of systemic lupus erythematosus (SLE). We describe a 24-year-old male with type IV lupus nephropathy as a presenting manifestation of SLE. He presented with improvement of renal function following induction therapy with three pulses of methylprednisolone and 500 mg biweekly pulses of cyclophosphamide. However, a week after the first pulse of cyclophosphamide, the patient presented with a significant increase in legs edema and severe hyperkalemia...

A low Na, high K diet (LNaHK) is associated with a low rate of cardiovascular (CV) disease in many societies. Part of the benefit of LNaHK relies on its diuretic effects; however, the role of aldosterone (aldo) in the diuresis is not understood. LNaHK mice exhibit an increase in renal K secretion that is dependent on the large, Ca-activated K channel, (BK-α with accessory BK-β4; BK-α/β4). We hypothesized that aldo causes an osmotic diuresis by increasing BK-α/β4-mediated K secretion in LNaHK mice. We found that the plasma aldo concentration (P[aldo]) was elevated by 10-fold in LNaHK mice compared with control diet (Con) mice...

BACKGROUND: Renal involvement in Schistosoma mansoni infection is not well studied. The aim of this study is to investigate the occurrence of renal abnormalities in patients with hepatosplenic schistosomiasis (HSS), especially renal tubular disorders. METHODS: This is a cross-sectional study with 20 consecutive patients with HSS followed in a medical center in Maceió, Alagoas, Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2) after a 12-h period of water and food deprivation...

HYPOTHESIS: This study determined the parameters for predicting the clinical effects of eplerenone (Ep) add-on therapy on blood pressure (BP) and proteinuria in patients taking angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II type I receptor blockers (ARBs). MATERIALS AND METHODS: Patients were treated with a gradual increase of Ep to a final dose of 50 mg/day for 2 months. In 35 patients, the efficacy of Ep was evaluated by peripheral BP, proteinuria, and the transtubular K gradient (TTKG)...

BACKGROUND: To assess the prevalence of exercise-associated hyponatremia (EAH) in two 24-hour mountain bike (MTB) (R1,R2), one 24-hour running (R3) and one multi-stage MTB (R4) races held in the Czech Republic in a cluster of four cross-sectional studies. METHODS: In 27 ultra-mountain bikers (ultra-MTBers), 12 ultra-runners, and 14 multi-stage MTBers, fluid intake, changes (Δ) in body mass, hematocrit, plasma volume, plasma [Na+], plasma [K+], plasma osmolality, urine [Na+], urine [K+], urine specific gravity, urine osmolality, K+/Na+ ratio in urine, transtubular potassium gradient and glomerular filtration rate were measured and calculated...

BACKGROUND/AIMS: Kidney abnormalities are one of the main chronic complications of sickle cell disease (SCD). The aim of this study is to investigate the occurrence of renal tubular abnormalities among patients with SCD. METHODS: This is a prospective study with 26 SCD adult patients in Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2), after a 12h period of water and food deprivation. Fractional excretion of sodium (FENa), transtubular potassium gradient (TTKG) and solute free water reabsorption (TcH2O) were calculated...

OBJECTIVE: To describe a case of heparin-induced hyperkalemia and the role for transtubular potassium gradient (TTKG) to guide fludrocortisone therapy. CASE SUMMARY: A 52-year-old white male developed hyperkalemia after receiving intravenous unfractionated heparin (UFH) for atrial fibrillation during thyroid storm. Admission laboratory results were noteworthy for normal potassium levels, undetectable thyroid-stimulating hormone, and mild transaminitis. Treatment for thyroid storm was initiated but UFH was stopped because the international normalized ratio was subsequently found to be elevated...

When it comes to interpret parameters of electrolyte balance and kidney function, it is important to keep pathophysiology and the theory on reference intervals in mind. Hyponatremia is most often caused by excess water. A low sodium concentration in urine should prompt a clinical evaluation of volume status. In case of suspected acute kidney failure, fractionated sodium excretion and fractionated urea excretion are able to provide insights on prerenal or renal origin of the disorder. Disruption in potassium homoeostasis can occur due to changes in supply or renal elimination as well as due to changes in the potassium balance between the extra- and intracellular compartments...

OBJECTIVES: The aim of the present study was to determine urinary potassium (K⁺) loss (as measured by fractional excretion of K⁺ [FEK] and transtubular K⁺ gradient [TTKG]) in children with acute liver failure (ALF) and acute viral hepatitis (AVH) at the time of presentation to the hospital and day 45 of follow-up. METHODS: Twenty-five patients with ALF and 84 patients with AVH were worked up for clinical features, liver function tests, and hepatitis viral infections and monitored for outcome...

BACKGROUND: Add-on therapy with aldosterone receptor antagonists has been reported to lower blood pressure (BP) in patients with uncontrolled hypertension. We assessed potential predictors of this response. METHODS: In essential hypertensive patients with uncontrolled BP, despite the use of at least two antihypertensives, plasma renin and aldosterone concentrations and the transtubular potassium gradient (TTKG) were measured. Patients were treated with eplerenone 50 mg daily on top of their own medication...

A 76-year-old man was admitted to our hospital because of severe anemia. Routine screening revealed a sigmoid adenocarcinoma, and he underwent sigmoidectomy. Post-operatively, he developed rapidly progressive glomerulonephritis. He was positive for myeloperoxidase anti-neutrophil cytoplasmic antibody. A renal biopsy revealed idiopathic crescentic glomerulonephritis of the pauci-immune type. He was treated with methylprednisolone semi-pulse therapy with clinical improvement. After the steroid pulse therapy, he was given oral prednisolone, 40 mg per day, and oral trimethoprim (TMP), 160 mg, and sulfamethoxazole (SMX), 800 mg twice weekly for chemoprophylaxis against pneumocystis pneumonia...

BACKGROUND: Hypokalemia, serum potassium (K) < 3.5 mEq/L, is a serious and common clinical problem. The traditional diagnosis of renal potassium losses is 24-hr urine potassium (24U(K)) > or = 20 mEq/day during hypokalemia. Immediate replacement of potassium is often required to prevent complication but may normalize serum K during 24-hr urine collection and render the test inconclusive. MATERIAL AND METHOD: The authors examined the ability of urinary indices including 24U(K), transtubular potassium gradient (TTKG), fractional excretion of potassium (FE(K)), urine potassium-creatinine ratio (U(K/Cr)) and spot U(K) and introduced urine potassium per hour during the first 8 hours (U(K)/hr) as a novel index for evaluation of hypokalemia during treatment...

The aim of this study was to determine whether renal unresponsiveness to aldosterone associated with hyperkalemia is present in infants with acute pyelonephritis in the absence of significant urinary tract anomalies and to describe the clinical characteristics of patients presenting an inadequate renal response to hyperkalemia. The patient cohort comprised 113 infants with acute pyelonephritis (APN), based on the criteria of a temperature >38°C and significant bacteriuria. Serum and urine electrolytes, creatinine, osmolality, and renal tubular function tests were performed at diagnosis...

PURPOSE OF REVIEW: This review aims to illustrate why urea recycling may play an important role in potassium (K⁺) excretion and to emphasize its potential clinical implications. RECENT FINDINGS: A quantitative analysis of the process of intrarenal urea recycling reveals that the amount of urea delivered to the distal convoluted tubule is about two-fold larger than the quantity of urea excreted in the urine. As the number of osmoles delivered to the late cortical distal nephron (CCD) determines its flow rate when aquaporin 2 water channels have been inserted in the luminal membrane of principal cells, urea recycling may play an important role in regulating the rate of excretion of K⁺ when the distal delivery of electrolytes is not very high...

An 84-year-old man was referred to our hospital for atrioventricular block and severe hypokalemia. He had been treated for hypertension since 2007 with indapamide, a thiazide-like diuretic. His laboratory data had not been tested for a long time. One week before his first visit, he suffered from a common cold and anorexia. He was admitted to our hospital because his electrocardiogram showed ventricular flutter, and pulmonary arrest occurred at the time of his visit. Cardiopulmonary resuscitation was successfully performed...

This study presents a cross-sectional analysis of the hormonal alterations of patients with visceral leishmaniasis. The diagnosis was established by the bone marrow aspiration and polymerase chain reaction test. Primary adrenal insufficiency was observed in 45.8% of patients; low aldosterone/renin plasma ratio in 69.4%; low daily urinary aldosterone excretion in 61.1%; and low transtubular potassium gradient in 68.0%. All patients had normal plasma antidiuretic hormone (ADH) concentrations, hyponatremia, and high urinary osmolality...

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...

Severe hyperkalemia (>7 mmol/L) is a medical emergency because of possible fatal arrhythmias. We here report the case of a 58-year-old woman surviving extreme hyperkalemia (>10 mmol/L). The patient with a history of congestive heart failure, a DDD pacemaker and mild chronic renal insufficiency was admitted with progressive weakness and sudden onset of hypotension and bradycardia in the absence of any pacemaker action. Laboratory tests revealed an extreme serum potassium level of 10.1 mmol/L, with a slightly elevated serum creatinine of 149 μmol/L...

BACKGROUND: Transplant recipients treated with calcineurin inhibitors (CNIs) frequently show hyperkalemia, metabolic acidosis, and hypomagnesemia which could be deleterious for some patients. Conversion to inhibitors of mammalian target of rapamycin (mTOR) could improve these electrolytic disturbances. OBJECTIVE: To evaluate the potassium and magnesium changes due to converting patients from CNIs to mTOR inhibitors. METHODS: Retrospective review of 138 renal transplant patients who were converted from CNIs to mTOR inhibitors over a 6-month observation period...

The salt intake of the Japanese is among the highest in the world, leading to a high prevalence of salt-sensitive hypertension. To prevent this, salt restriction, suppression of the rennin-angiotensin-aldosterone system, and natriuresis are important. Therefore, the use of a combination of an angiotensin II receptor blocker and thiazide diuretics is used for antihypertensive treatment. Some randomized controlled studies suggested that thiazide diuretics are useful not only to lower blood pressure, but also to prevent cardiovascular events and improve prognosis in the elderly, who are prone to being salt-sensitive...