Gitelman's syndrome is genetically distinct from other forms of Bartter's syndrome

In the past the term Bartter's syndrome has been used to describe a spectrum of inherited renal tubular disorders with hypokalemic metabolic alkalosis and overlapping and additional clinical and biochemical features. Pathogenesis remained uncertain until recently Gitelman's syndrome, the hypokalemic-hypomagnesemic variant with hypocalciuria, was linked to the gene encoding the thiazide-sensitive Na-Cl-cotransporter (TSC) located on chromosome 16q. Various mutations in the TSC gene were identified in patients with Gitelman's syndrome. To clarify whether different forms of hypokalemic tubular disorders (HTD) represent variable phenotypes of a common genetic defect, we performed linkage analyses in 17 families with different symptoms of HTD with four highly polymorphic chromosome 16 DNA markers closely linked to the TSC gene. Linkage of Gitelman's syndrome to the TSC locus was confirmed in our families with a maximum two-point Lod score Z = 4.70 (theta = 0.001) for marker locus D16S526. Highly negative LOD scores were obtained at this locus in our families with classic Bartter's syndrome (Z = 9.89, theta = 0.001) and hyperprostaglandin E syndrome (Z = -11.24, theta = 0.001). Our data prove that Gitelman's syndrome is genetically distinct from classic Bartter's syndrome and hyperprostaglandin E syndrome. It remains unknown if classic Bartter's syndrome and hyperprostaglandin E syndrome are caused by a common genetic defect.     

Phenotype resembling Gitelman's syndrome in mice lacking the apical Na+-Cl- cotransporter of the distal convoluted tubule

Mutations in the gene encoding the thiazide-sensitive Na+-Cl- cotransporter (NCC) of the distal convoluted tubule cause Gitelman's syndrome, an inherited hypokalemic alkalosis with hypomagnesemia and hypocalciuria. These metabolic abnormalities are secondary to the deficit in NaCl reabsorption, but the underlying mechanisms are unclear. To gain a better understanding of the role of NCC in sodium and fluid volume homeostasis and in the pathogenesis of Gitelman's syndrome, we used gene targeting to prepare an NCC-deficient mouse. Null mutant (Ncc-/-) mice appear healthy and are normal with respect to acid-base balance, plasma electrolyte concentrations, serum aldosterone levels, and blood pressure. Ncc-/- mice retain Na+ as well as wild-type mice when fed a Na+-depleted diet; however, after 2 weeks of Na+ depletion the mean arterial blood pressure of Ncc-/- mice was significantly lower than that of wild-type mice. In addition, Ncc-/- mice exhibited increased renin mRNA levels in kidney, hypomagnesemia and hypocalciuria, and morphological changes in the distal convoluted tubule. These data indicate that the loss of NCC activity in the mouse causes only subtle perturbations of sodium and fluid volume homeostasis, but renal handling of Mg2+ and Ca2+ are altered, as observed in Gitelman's syndrome.     

Three cases of Gitelman's syndrome possibly caused by different mutations in the thiazide-sensitive Na-Cl cotransporter

Three adult Japanese cases of Gitelman's syndrome were characterized by secondary aldosteronism, hypokalemic alkalosis, hypomagnesemia, and hypocalciuria. Two were revealed to be familial cases. A mutation in the thiazide-sensitive Na-Cl cotransporter gene, which had already been confirmed in one family (Takeuchi et al. J Clin Endocrinol Metab 81: 4496,1996), was not detected in the other two cases. These observations may possibly support the previous report (Simon et al. Nature Genet 12: 24, 1996) that Gitelman's syndrome is caused by a variety of mutations in the thiazide-sensitive Na-Cl cotransporter.     

Orthodontic treatment demand--differences between urban and rural areas

The recently cloned bumetanide-sensitive Na/K/2Cl cotransporters (ENCC2-3) and thiazide-sensitive Na/Cl cotransporter (ENCC1) have important roles in sodium chloride absorption and secretion, cell volume regulation, ammonium accumulation in medullary interstitium, and ammonium excretion. Genetic mutations of bumetanide-sensitive Na/K/2Cl cotransporters and thiazide-sensitive Na/Cl cotransporter cause the hereditary hypokalemic alkalosis of some Bartter's syndrome and Gitelman's syndrome, respectively. The transporters are sensitive to diuretics and several hormones. Dehydration and acidosis influence the gene expression of ENCC3 but not of ENCC1-2. In contrast, sodium loading increases ENCC2 protein expression in the outer medulla.     

Risk factors for acute renal failure in trauma patients

OBJECTIVE: To elucidate the risk factors for the development of acute renal failure (ARF) in severe trauma. DESIGN: Prospective observational study. SETTING: A general intensive care unit (ICU) of a university hospital. PATIENTS: A cohort of 153 consecutive trauma patients admitted to the ICU over a period of 30 months. RESULTS: Forty-eight (31%) patients developed ARF. They were older than the 105 patients without ARF (p = 0.002), had a higher Injury Severity Score (ISS) (p < 0.001), higher mortality (p < 0.001), a more compromised neurological condition (p = 0.007), and their arterial pressure at study entry was lower (p = 0.0015). In the univariate analysis, the risk of ARF increased by age, ISS > 17, the presence of hemoperitoneum, shock, hypotension, or bone fractures, rhabdomyolysis with creatine phosphokinase (CPK) > 10000 IU/l, presence of acute lung injury requiring mechanical ventilation, and Glasgow Coma Score < 10. Sepsis and use of nephrotoxic agents were not associated with an increased risk of ARF. In the logistic model, the need for mechanical ventilation with a positive end-expiratory pressure > 6 cm H2O, rhabdomyolysis with CPK > 10000 IU/l, and hemoperitoneum were the three conditions most strongly associated with ARF. CONCLUSIONS: The identified risk factors for post-traumatic acute renal failure may help the provision of future strategies.     

Abnormal renal magnesium handling

The normal fractional urinary excretion of filtered magnesium is about 5%. In magnesium deficiency in man, the kidneys can normally reduce the 24-hour urinary magnesium excretion to less than 1 mmol (24 mg) via unknown mechanisms, and initially without a fall in plasma magnesium concentration. Renal magnesium wasting may be defined as a urinary excretion greater than 1 mmol/day in the presence of hypomagnesemia (plasma magnesium < 0.7 mmol/l). Congenital renal magnesium wasting occurs in several syndromes including Bartter's syndrome in which it is associated with hypercalciuria, and the defect may be in the thick ascending limb of Henle's loop, and Gitelman's syndrome in which there is hypocalciuria, and the defect may be in the distal convoluted tubule. Other causes of renal magnesium wasting include diabetes mellitus, hypercalcemia and diuretics. Magnesium wasting may also result from various toxicities including those of cis-platinum, in which the biochemical features resemble Gitelman's syndrome, and those of aminoglycosides, pentamidine and cyclosporin. Calcitriol deficiency may also contribute to renal magnesium wasting in some circumstances. Mild hypermagnesemia may occur in familial hypocalciuric hypercalcemia and may reflect abnormal sensitivity of the loop of Henle to calcium and magnesium ions. By contrast, the hypermagnesemia that occurs in chronic renal failure results from the reduced glomerular filtration of magnesium.     

Acute renal failure syndromes in human immunodeficiency virus infection

Two major groups of renal complications in human immunodeficiency virus (HIV) disease are a spectrum of disorders that result in potentially reversible acute renal failure, primarily acute tubular necrosis (ATN), and HIV-associated nephropathy (HIVAN), predominantly focal and segmental glomerulosclerosis (FSGS), leading to end-stage renal disease (ESRD). Fluid-electrolyte and acid-base derangements frequently encountered in acquired immune deficiency syndrome (AIDS) are major risk factors for the development of acute renal failure (ARF). HIVAN is an unusual form of poorly responsive glomerular disease characterized by nephrotic syndrome, FSGS, and a rapid fulminant progression to ESRD. ARF syndromes encountered in HIV patients are diverse in nature; many are similar to that in non-HIV subjects, whereas some are more common and unique. In general, HIV disease patients with ARF are younger and much sicker. Although ATN secondary to ischemic and toxic injuries is the commonest ARF syndrome, urinary obstruction is a rare cause of severe renal failure. In many AIDS patients afflicted with complicated infections and multi-organ failure, ATN is a terminal event, whereas in others treated aggressively, ARF is associated with good prognosis. In our large comparative study of severe ARF, recovery of renal function and mortality were determined by patient's general hemodynamic status, and not by the presence or absence of HIV infection. The prognosis of hemolytic uremic and thrombotic thrombocytopenic purpura syndromes often observed in HIV patients is much worse than in non-HIV patients. The syndrome of crystalluria-induced ARF is common, and protease inhibitor induced disease is confined to HIV patients.     

Chondrocalcinosis is a feature of Gitelman's variant of Bartter's syndrome. A new look at the hypomagnesemia associated with calcium pyrophosphate dihydrate crystal deposition disease

The occurrence of chondrocalcinosis in patients with Bartter's syndrome has been reported as a typical example of hypomagnesemia-associated calcium pyrophosphate dihydrate crystal (CPPD) deposition disease. However, hypomagnesemia is a feature of Gitelman's variant of Bartter's syndrome, whereas serum magnesium levels are normal in Bartter's syndrome strictly speaking. We managed four patients with chondrocalcinosis and hypomagnesemia who met criteria for Gitelman's disease, including hypomagnesemia, hypokalemia with normal or high urinary potassium excretion, hypocalciuria, and normal blood pressure. Based on our experience with these patients, we argue that many cases of chondrocalcinosis and hypomagnesemia ascribed in previously published articles to Bartter's syndrome were due to Gitelman's syndrome.     

Synergistic renal protection by combining alkaline-diuresis with lipid peroxidation inhibitors in rhabdomyolysis: possible interaction between oxidant and non-oxidant mechanisms

BACKGROUND AND PURPOSE: Heme-proteins, besides causing renal tubular obstruction, may contribute to rhabdomyolysis-induced renal injury through a heme-iron-mediated lipid peroxidation process. In the present study, we compared the combined therapy of a lipid peroxidation inhibitor, 21-aminosteroid (21-AS) and fluid-alkaline-mannitol (FAM) diuresis with either of them alone to determine the efficacy of the combination therapy and to delineate the roles of lipid peroxidation and cast formation. METHODS AND RESULTS: Employing Raman spectroscopy, we confirmed in vitro the ability of 21-AS to inhibit iron-induced fatty acid peroxidation. 21-AS was then administered to rats developing renal failure from glycerol-induced rhabdomyolysis. Although 21-AS inhibited rhabdomyolysis-induced plasma and renal lipid peroxidation, renal protection was incomplete. Administration of FAM to inhibit cast formation afforded a better renal protection. However, when these therapies were combined to inhibit both lipid peroxidation and cast formation, there was a synergistic renal functional protection. This was accompanied by a maximum inhibition of renal and plasma lipid peroxidation, as well as, renal tubular necrosis and cast formation. Compared to combination therapy, FAM therapy alone, despite identical volume, was accompanied by a higher tubular necrosis and cast formation. CONCLUSIONS: That combining a lipid peroxidation inhibitor with fluid-alkaline diuresis in rhabdomyolysis further lowers renal lipid peroxidation, tubular necrosis and cast formation and synergistically limits renal dysfunction (i) supports a role for lipid peroxidation in the pathophysiology of rhabdomyolysis ARF, (ii) underscores the role of the intratubular heme retention, a cause for tubular obstruction as well as a source for prodigious amount of iron, likely involved in the lipid peroxidation, and (iii) raises the possibility of interactions between non-oxidant and oxidant mechanisms.     

Evidence from desensitization studies for distinct receptors for ATP and UTP on the rat superior cervical ganglion

A 44-year-old woman with scleroderma and Sj?gren's syndrome developed altered consciousness, acute renal failure, and rhabdomyolysis. She had no history of trauma, seizures, alcohol abuse, hyperthermia, or other possible causative factors for rhabdomyolysis. A high serum salicylate level indicated a diagnosis of salicylate intoxication. Medical history after recovery revealed chronic salicylate ingestion for severe headaches. This is possibly the first reported case of rhabdomyolysis caused by chronic salicylate intoxication. Continuous hemodiafiltration early in hospitalization was an effective treatment.     

Leukocytes, cell adhesion molecules and ischemic acute renal failure

Ischemic acute renal failure (ARF) is a common clinical syndrome, associated with high morbidity and mortality, for which there is no specific therapy. Polymorphonuclear neutrophils (PMN) recruited during reperfusion have been implicated as mediators of renal parenchymal injury in ischemic ARF. Leukocyte adhesion molecules appear to facilitate PMN recruitment in this setting. Complementary studies using monoclonal antibodies, antisense oligonucleotides and gene "knock-out" indicate that blockade of CD11/CD18 integrins and intercellular adhesion molecule-1 (ICAM-1) attenuates ARF in some experimental models of renal ischemia. These exciting observations may herald the development of novel anti-adhesion strategies for use in human disease.     

Acute renal failure: controversies, clinical trials, and future directions

Acute renal failure (ARF) is an important clinical syndrome. Despite the frequent occurrence of ARF, nephrologists have not made major therapeutic inroads in the treatment or prevention of ARF. This article will speculate as to why it has been so difficult to gain a substantial foothold in the ongoing battle against ARF. First, some of the major controversies regarding the pathogenesis of ARF will be considered. Scientific debates regarding the mechanisms of ARF have greatly enriched the scientific literature, but may have slowed the development of clinically applicable therapies. Controversies regarding the treatment of ARF will then be discussed. Next, the fate of several recent clinical trials in ARF will be examined. Finally, the future directions that research in ARF may pursue will be contemplated.     

Physiopathological study in 2 cases of Bartter's syndrome

Batter's syndrome is characterized by retardation in growth pitressin-resistant hypostenuria, hypokalemic alkalosis, high activity of the jux angiotensin-renine-aldosterone system with normal blood pressure; vascular insensibility to angiotensin and hypertrophy and hyperplasia of the juxtaglomerular apparatus. In both patients we studied, we found negative balance of sodium and potassium conditioned to a renal loss of them.     

Consolidation of massive bone allografts in limb-preserving operations for bone tumours

Acute renal failure (ARF) is a syndrome in which the kidneys are unable to excrete the products of metabolism. The failure of renal function is rapid in its onset but potentially reversible. It occurs rapidly, within 8 weeks of renal injury resulting in a rapid increase in serum urea and creatinine concentrations in patients with previously normal renal function. It is a condition traditionally associated with a high mortality rate, often due to the complications of sepsis, delayed wound healing and disrupted haemocoagulation. Survivability has been demonstrated to be improved by early appropriate nutritional support (Bartlett et al., 1986) although in practice this is often difficult to achieve as nutritional support is complex. In the past high morbidity and mortality rates were related to infections and inadequate nutritional intake. This resulted from unnecessary protein restrictions in an attempt to control uraemic symptoms (Thomas, 1988). To a large extent survivability of ARF has still not been greatly improved even with modern antibiotics and the careful dietary assessment of ARF patients. This reflects the complexity of managing patients with this condition. However, appropriate dietary management of ARF patients is essential to improve their long-term prognosis. Although the precise form this takes remains a contentious issue amongst clinicians.     

5 children with hypokalemia, hypomagnesemia and hypocalciuria (Gitelman syndrome) in one family

Gitelman's syndrome was diagnosed in five siblings. The parents were relatives in the third remove. Gitelman's syndrome is a rare autosomal recessive hereditary magnesium reabsorption defect in the distal tubule. It is characterized by episodes of muscle weakness, usually accompanied by abdominal pain and vomiting. Tetany may occur during a febrile illness. Patients are of normal height and weight and have normal blood pressures. Sometimes eczematous skin lesions are found. Biochemically there is hypokalaemia, hypomagnesaemia and alkalosis. Urinary excretion rates of potassium and magnesium are elevated, the excretion of calcium is diminished. Treatment consists of oral suppletion of magnesium, sometimes also with oral potassium. A potassium-sparing diuretic may be used. The prognosis appears to be good.     

Carrot DNA-methyltransferase is encoded by two classes of genes with differing patterns of expression

There is a wide variety of renal tubular disorders affecting children. Understanding the pathophysiology of each disease assists in the recognition and treatment of these diseases, which can have profound effects on a child's growth and development. We review some of the more common tubular disorders found in children, emphasizing those conditions in which recent advances have been made in understanding of the specific genetic or physiological defect responsible: Fanconi's syndrome, cystinuria, renal tubular acidosis, and the hypokalemic metabolic alkaloses. Current recommendations are presented for diagnosing and treating these conditions.     

A prospective study of ward referrals for renal disease at a Jamaican and a United Kingdom hospital

Seventy ward referrals for renal disease were prospectively studied at each of two tertiary hospitals: University Hospital of the West Indies (UHWI), Kingston, Jamaica and Nottingham City Hospital (NCH), England. At UHWI, the referral population was significantly younger, 89% being less than 60 years of age compared to 40% at NCH (p < 0.05). The leading cause of acute renal failure (ARF) at UHWI was systemic lupus erythematosus (SLE) followed by acute tubular necrosis (ATN). The leading causes of ARF at NCH were ATN and obstructive uropathy. Primary renal disease and diabetes mellitus were the major causes of end-stage renal disease (ESRD) at both centres, followed by SLE and hypertension at UHWI and renovascular disease and chronic pyelonephritis at NCH. Nephrotic syndrome occurred more frequently at UHWI than at NCH but the numbers were small (p < 0.05). Mortality rates were similar among patients with ARF and nephrotic syndrome at both centres, but were higher for patients with chronic renal failure (CRF) at UHWI than at NCH (p < 0.05). Continuous ambulatory peritoneal dialysis (CAPD) was a frequent mode of renal replacement therapy at NCH (76% v 19% on haemodialysis). At UHWI, CAPD was not available and 45% of patients with ESRD were not offered maintenance dialysis because of inadequate facilities. The major difference in management and outcome between the two centres occurred in cases with CRF, suggesting that survival in patients with CRF in Jamaica could be improved if this therapeutic modality was available.     

Behr''s syndrome. A report of 2 siblings studied by MR

Neuroleptic malignant syndrome is an idiosyncratic reaction associated with the use of neuroleptic drugs. We report a case of this rare syndrome in a head injury patient associated with some unusual features: rhabdomyolysis with a high level of creatine kinase, the development of acute renal failure, the early use of continuous venovenous haemofiltration in treatment and rigidity that was refractory to conventional treatment with dantrolene and bromocriptine. The diagnosis in patients with multiple injuries must be based on a high index of suspicion.     

How to manage HIV seropositive or AIDS patients in rural Burkina Faso?

The application of molecular biology to the study of electroneutral cation-chloride cotransporters has been extremely successful, resulting in the identification of a new gene family of five membrane proteins. The function, expression, and regulation of these important proteins can increasingly be described in molecular terms. In addition, mutations in two renal cation-chloride transporter genes have been found in patients with Bartter's and Gitelman's syndromes, autosomal recessive disorders of renal salt excretion.     

Focal nodular hyperplasia of the liver and hypercholesterolemia in a child with VACTERL syndrome

Ten cases of acute renal failure (ARF) were seen in the period from July 1990 to August 1991 in the Nephrology Department of the SIMS Hospital, Srinagar. All were males in the age group of 18-28 years and in apparent good health when apprehended by the police. There was alleged history of physical torture of different types. All had been beaten on the buttocks, back and limbs; in addition, 2 cases had been given repeated electric shocks and 1 case put to 'sit-and-stand' exercise for about 3 h. The interval between the first day of torture till they came to our observation varied from 4 to 11 days. The main clinical features at the time of presentation were generalized aches and weakness (10), oligoanuria (9), vomiting (8), hypertension (6), acidosis (10), facial puffiness and pedal edema (6), fever and shivering (3), pulmonary edema (2), stupor (4), and hyperkalemia (5). All the cases had an established ARF (serum creatinine 668-1,997 mumol/l and serum urea 21.8-71.8 mmol/l) when first seen. Muscle enzymes, creatine phosphokinase, lactic dehydrogenase and serum glutamic oxaloacetic transaminase were all significantly raised indicating rhabdomyolysis. All showed evidence of myoglobin casts in urine. Nine had oliguric and 1 had nonoliguric ARF. All except the 1 case with nonoliguric ARF were managed with peritoneal dialysis and/or hemodialysis. All recovered. Early recognition of ARF is important since the main attention in such cases is directed towards the surgical aspect.