1/55. Biochemical examination of mother's urine is useful for prenatal diagnosis of bartter syndrome.bartter syndrome is characterized by renal potassium and chloride loss, hypokalaemia, hypochloraemic metabolic alkalosis and increased plasma renin activity along with elevated angiotensin ii and hyperaldosteronism. For diagnosis we conducted biochemical examinations of both amniotic fluid and the mother's urine. Except for potassium, amniotic fluid electrolytes in a mother with a fetus with bartter syndrome were high. Urinary chloride, sodium and calcium were very low. Thus, the latter parameters may allow prediction of fetal bartter syndrome during the prenatal period.- - - - - - - - - - ranking = 1keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
2/55. Bartter's syndrome in pregnancy: a case report and review.Bartter's syndrome is a rare renal tubular disorder, involving juxtaglomerular cells hyperplasia, characterized by normotensive hyper-reninism and secondary hyperaldosteronism, marked renal loss of potassium and profound hypokalaemia. Both clinical and biochemical features are heterogeneous, ranging from the incidental finding in an asymptomatic patient to marked clinical features of hypokalaemia. Inheritance is likely to be an autosomal recessive. We present a case of Bartter's syndrome complicating pregnancy in a Chinese woman. We documented an increasing demand for potassium supplement during pregnancy which stabilized by mid-trimester. The absence of pregnancy complications such as polyhydramnios indicated that the fetus was unlikely to be affected by the condition.- - - - - - - - - - ranking = 1keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
3/55. Bartter's syndrome. New insights into pathogenesis and treatment.Discussed here is a patient with normotension, hypokalemic alkalosis, hyperreninemia, hyperaldosteronism, juxtaglomerular cell hyperplasia and insensitivity to the pressor effects of angiotensin (Bartter's syndrome). The hyperreninemia and hyperaldosteronism were both suppressible with volume expansion. hypokalemia was correctible both short-term with potassium chloride infusions and long-term with spironolactone. Nevertheless, the abnormal pressor response to infused angiotensin could not be corrected by these maeuvers, suggesting that this defect is likely to be of primary pathophysiologic significance. We found that potassium loading markedly stimulated aldosterone excretion. This may explain the inadequacy of potassium supplementation alone to correct the hypokalemia and the observed "escape" from the potassium conserving effects of spironolactone seen in patients with Bartter's syndrome. The administration of propranolol in large doses only partially suppressed the marked hyperreniemia of our patient and failed to prevent a subsequent rise in the renin level which was associated with spironolactone therapy. In contrast, suppression of the renin level to normal was demonstrated by sodium loading. It is suggested that patients with Bartter's syndrome be treated simultaneously with large doses of spironolactone and a high sodium intake.- - - - - - - - - - ranking = 2keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
4/55. bartter syndrome. Typical facies and normal plasma volume.Two girls with hypokalemic and hypochloremic metabolic alkalosis and failure to thrive were found to have bartter syndrome at ages 9 and 6 months. Both had normal blood pressures despite substantial elevation of plasma renin activity and evidence of secondary hyperaldosteronism. A similarity in facial features, including prominent forhead, a large head, triangular facies with drooping mouth, and large eyes and pinnae, was noted in these two infants and in published pictures of other infants with the syndrome. Although the normotension associated with substanital elevation of plasma renin activity and hyperaldosteronism in bartter syndrome has been considered the effect of hypovolemia, a normal or slightly elevated plasma volume was found in these infants, suggesting that in certain cases an alternate mechanism for the depressed response to renin may be present.- - - - - - - - - - ranking = 2keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
5/55. Functional characterization of a calcium-sensing receptor mutation in severe autosomal dominant hypocalcemia with a Bartter-like syndrome.The extracellular Ca(2 )-sensing receptor (CaSR) plays an essential role in extracellular Ca(2 ) homeostasis by regulating the rate of parathyroid hormone (PTH) secretion and the rate of calcium reabsorption by the kidney. Activation of the renal CaSR is thought to inhibit paracellular divalent cation reabsorption in the cortical ascending limb (cTAL) both directly and indirectly via a decrease in NaCl transport. However, in patients with autosomal dominant hypocalcemia (ADH), caused by CaSR gain-of-function mutations, a defect in tubular NaCl reabsorption with renal loss of NaCl has not been described so far. This article describes a patient with ADH due to a gain-of-function mutation in the CaSR, L125P, associated with a Bartter-like syndrome that is characterized by a decrease in distal tubular fractional chloride reabsorption rate and negative NaCl balance with secondary hyperaldosteronism and hypokalemia. The kinetics of activation of the L125P mutant receptor expressed in HEK-293 cells, assessed by measuring CaSR-stimulated changes in intracellular Ca(2 ) and ERK activity, showed a dramatic reduction in the EC(50) for extracellular Ca(2 ) compared with the wild-type and a loss-of-function mutant CaSR (I40F). This study describes the first case of ADH associated with a Bartter-like syndrome. It is herein proposed that the L125P mutation of the CaSR, which represents the most potent gain-of-function mutation reported so far, may reduce NaCl reabsorption in the cTAL sufficiently to result in renal loss of NaCl with secondary hyperaldosteronism and hypokalemia.- - - - - - - - - - ranking = 2keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
6/55. Hypokalemic metabolic alkalosis--three case reports.The two most common forms of inherited normotensive hypokalemic metabolic alkalosis are Bartter's and Gitelman's syndromes. Bartter's syndrome typically present with normal or increased calcium excretion. Hypomagnesemia occurs in only one third of affected individuals. In contrast, hypomagnesemia and hypocalciuria are considered hallmarks of Gitelman's syndrome. In most patients, the symptom of muscle weakness and polyuria occur early in life, which may be attributed to potassium depletion. Despite hyperaldosteronism, the patients tend to be normotensive, which is at least explained by vascular hyperresponsiveness to prostaglandins. Therapeutic approaches to Bartter's and Gitelman's syndromes include potassium supplementation, prostaglandin synthesis inhibitors (nonsteroid anti-inflammatory agents), aldosterone antagonists and converting enzyme inhibitors. Three patients with hypokalemia, normal blood pressure, metabolic alkalosis, hyperreninemia and hyperaldosteronism are described. Two patients had Bartter's syndrome and one patients had Gitelman's syndrome.- - - - - - - - - - ranking = 2keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
7/55. Heterozygous mutations of the gene for Kir 1.1 (ROMK) in antenatal bartter syndrome presenting with transient hyperkalemia, evolving to a benign course.Bartter-like syndrome encompasses a set of inherited renal tubular disorders associated with hypokalemic metabolic alkalosis, renal salt wasting, hyperreninemic hyperaldosteronism, and normal blood pressure. Antenatal bartter syndrome, a subtype of Bartter-like syndrome, is characterized by polyhydramnios, premature delivery, life-threatening episodes of fever and dehydration during the early weeks of life, growth retardation, hypercalciuria, and early-onset nephrocalcinosis. Mutations in the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) and ATP-sensitive inwardly rectifying potassium channel (ROMK) of the thick ascending limb of Henle's loop have been identified in the antenatal bartter syndrome. We report the identification of two heterozygous mutations of the gene for Kir 1.1 (ROMK) from an antenatal bartter syndrome patient who presented at birth with mild salt wasting and a biochemical findings that mimicked primary pseudohypoaldosteronism type 1, such as hyperkalemia and hyponatremia, and evolved to a relatively benign course. We have identified amino acid exchanges Arg338Stop and Met357Thr in the gene exon 5 for ROMK by PCR and direct sequencing. Both mutations alter the C-terminus of the ROMK protein, and can affect channel function.- - - - - - - - - - ranking = 1.0705497856363keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
8/55. bartter syndrome complicated by immune complex nephropathy. Case report and literature review.The unusual coincidence of bartter syndrome and C1q nephropathy is described and the literature reviewed. An African-American girl presented at 4 years of age with acute hyponatremic dehydration and failure to thrive. Persistent hypokalemic alkalosis and secondary hyperaldosteronism were found. The case was atypical for bartter syndrome in that proteinuria (0.19 g/day) was present. Renal biopsy showed juxtaglomerular hyperplasia and C1q nephropathy. Molecular analysis showed deletion of the renal chloride channel gene (CLCNKB) typical of autosomal recessive childhood bartter syndrome. Chronic sodium and potassium chloride replacement therapy together with indomethacin normalized her metabolic status, and she experienced catch-up growth. proteinuria persisted, however. This is the first documentation of C1q nephropathy, in mild form, complicating autosomal recessive bartter syndrome. This case shows the importance of the renal biopsy and of molecular analysis in delineating the cause of atypical nephropathy associated with bartter syndrome. These findings add to the evidence of a possible association between the congenital syndrome and acquired immune complex nephropathy.- - - - - - - - - - ranking = 1keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
9/55. Cardiomyopathy in an adult with Bartter's syndrome and hypokalemia. Hemodynamic, angiographic and metabolic studies.A case of an adult with Bartter's syndrome (hyperplasia of the juxtaglomerular complex with hyperaldosteronism and hypokalemic alkalosis) is described; the patient had the unusual manifestation of cardiomyopathy, probably secondary to severe hypokalemia. Results of metabolic studies and kidney biopsy were consistent with Bartter's syndrome; angiographic and hemodynamic findings were abnormal. The cardiomyopathy was confirmed at autopsy after the patient's sudden death. Conclusions from this case are that severe hypokalemia can pose a serious threat both immediately in the form of dangerous arrhythmias and in the long term in the form of cardiomyopathy.- - - - - - - - - - ranking = 1keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
10/55. Distal nephron function in Bartter's syndrome: abnormal conductance to chloride in the cortical collecting tubule?Five patients with the clinical patterns of Bartter's syndrome underwent a series of clearance studies in order to characterize the underlying tubule defect. Free water generation during maximal water diuresis (CH2O), expressed as percentage of the distal delivery (CH2O CCl), was lower in the patients (72.5 /- 3.2%) than in controls (84.4 /- 5.5, p < 0.0001). During maximal water diuresis and furosemide administration (40 mg i.v. as bolus), NaCl reabsorption along the diluting nephron segments could be separated into 2 components, that occurring in the loop of henle (DRNaHL) and that occurring in tubule segments beyond the macula densa (DRNaDT): DRNaHL was normal, while DRNaDT was reduced (3.1 /- 0.8 vs. 6.2 /- 2.5 ml/min in controls, p < 0.015). Thus, according to this furosemide protocol, our patients had normal solute reabsorption in the loop of henle but reduced NaCl reabsorption in tubule segments beyond the macula densa. During 0.9% saline infusion (2 liters in 2 h, after stimulation of distal Na reabsorption with fludrocortisone) fractional excretion (FE) of K showed a linear rise with the increase of FECl-FEK, however, was much higher in the patients than in controls for every FECl level. In contrast, the infusion of Na2SO4, after fludrocortisone administration, induced similar FEK increases in patients and in controls. Thus, in these patients Na reabsorption in the distal nephron (possibly the cortical collecting tubule) was associated with the generation of a higher than normal electric potential gradient in the presence of Cl but not of another poorly reabsorbable anion, such as SO4(2-). These observations indicate that, in our patients, Henle's loop function is normal, while the collecting tubule function is abnormal. We suggest that NaCl wasting and enhanced tubular secretion of H and K in our patients might result from an abnormally low conductance to Cl in distal nephron site(s) where Na reabsorption is electrogenic, possibly the cortical collecting tubule. A larger than normal transtubular electric gradient would be generated by Na reabsorption, causing: (1) a direct stimulation of tubular secretion of K and H (leading to hypokalemia and alkalosis) and (2) inhibition of the reabsorption of Na ('trapped' into the tubular lumen by electric forces), with consequent extracellular volume contraction, hyperreninemia and hyperaldosteronism.- - - - - - - - - - ranking = 1keywords = hyperaldosteronism, aldosteronism (Clic here for more details about this article) |
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