Renal tubular acidosis in a case of Shwachman's syndrome

We describe metabolic acidosis in a 15-month-old girl with clinical features of Shwachman's syndrome. Renal function tests indicated that the patient had type 1 renal tubular acidosis. Based on our findings and other reports of renal tubular dysfunction in patients with Shwachman's syndrome, we conclude that it is important to look for a possible renal tubular defect in this syndrome.     

Marble brain disease in two Saudi Arabian siblings

Marble brain disease, also known as Guibaud-Vainsel syndrome, is a syndrome consisting primarily of renal tubular acidosis, cerebral calcification and osteopetrosis. The majority of reports originate from the Middle East. It is an autosomal recessive condition owing to carbonic anhydrase type II deficiency in renal and brain cells with a variant form of osteopetrosis. We report two siblings with this condition from Saudi Arabia. Both cases improved in both somatic growth and mental development after commencing treatment for renal tubular acidosis in the form of alkaline therapy and potassium supplementation.     

Fanconi syndrome in a patient with a variant of isovaleric acidemia

Fanconi syndrome with proximal renal tubular acidosis is caused by a variety of anatomic, functional and metabolic disorders. We report a patient with a variant of isovaleric acidosis who developed proximal tubular acidosis. This patient was able to acidify the urine during metabolic acidosis, developed a hyperchloremic metabolic acidosis, and needed 24 mEq/kg/day of bicarbonate to maintain normal serum bicarbonate. She had a FE Bicarbonate of 12 +/- 4% during bicarbonate infusion. Isovaleric acidosis may be another toxic cause of proximal RTA.     

Congenital Nephrotic Syndrome with Focal Segmental Glomerular Sclerosis, Renal Insufficiency and Tubular Dysfunction

A patient with congenital nephrotic syndrome with focal segmental glomerular sclerosis is reported. There was moderate renal insufficiency, proximal renal tubular acidosis, hematuria and glycosuria. The glomerular basement membrane showed irregular thickening, splitting of the lamina densa and reticulation of the lamina rara interna. In addition to the features of the nephrotic syndrome and renal insufficiency, tubular dysfunction is one of the early manifestations of this disease.     

Renal tubular acidosis

In the past decade major advances in our understanding of renal tubular hydrogen ion secretion and bicarbonate reabsorption have provided new insight into the pathophysiology of renal tubular acidosis. Thus "fragment to fragment clings" and the number of disorders categorized within the syndrome grows, until we have come to know and name four types, with many subtypes. We hope this new perspective provides a basis for the physician to recognize renal tubular acidosis in its several forms so that an informed decision may be arrived at in choosing the best therapy. The physician may also be prepared to reasonably project the prognosis for each patient. We also hope that our detailed examination of renal acidification will provide a reference for delineation of new clinical expressions of acid-base disorders and kidney malfunction certain to be described in the years ahead.     

Renal tubular acidosis and nerve deafness.

Two brothers are described with renal tubular acidosis and nerve deafness: the elder also had rickets and hypokalaemia. The parents were unaffected. Studies of urinary acidification and bicarbonate excretion were consistent with a distal tubular abnormality. This report strengthens the view previously proposed in similar cases that nerve deafness and renal tubular acidosis constitute a genetic entity. Examination for nerve deafness is indicated in any child with renal tubular acidosis.     

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??Objective??To analyze the clinical features and the results of genetic diagnosis in children with hypokalemic renal tubular diseases. Methods??The clinical data of 38 patients with hypokalemic renal tubular diseases were analyzed retrospectively??who were treated in Children’s Hospital Affiliated to Shanghai Jiao Tong University from Jan. 2010 to Jan. 2016. Results??Totally 38 patients with hypokalemic renal tubular diseases were enrolled in this study. There were 18 cases of renal tubular acidosis??RTA?? including 17 cases of type??RTA and 1 case of type?? RTA. There were 11 cases of Bartter syndrome??5 cases of Gitelman syndrome and 4 cases of Fanconi syndrome. The common clinical manifestations of hypokalemic renal tubular diseases included myasthenia??nausea??vomiting??polydipsia??polyurine and growth retardation. One case of Fanconi syndrome progressed to chronic Kidney disease??phase ????while the other
children had normal renal function. Glomerular proteinuria was found in 1??1 and 3 children with Bartter syndrome??Gitelman syndrome and Fanconi syndrome??respectively. Additionally??1 case with Fanconi syndrome has tubular proteinuria. However??urinary trace proteins associated with glomerular and tubular injury commonly elevated in these hypokalemic renal tubular diseases. Genetic analysis showed a new potential heterozygous mutations of ATPV0A4 in type??RTA and three heterozygous mutations of SLC12A3 in Gitelman syndrome. Conclusion??The clinical symptoms vary in patients and are featured mainly by myasthenia??nausea??vomiting??polydipsia??polyurine and growth retardation. Glomerular and tubular injuries are commonly found in hypokalemic renal tubular diseases. Moreover??genetic diagnosis may be helpful in diagnosis??treatment and genetic counseling.     

Renal tubular acidosis does not alter circulating values of calcitriol

In 10 patients with renal tubular acidosis, seven with type I and three with Fanconi syndrome, simultaneous measurements of vitamin D metabolites and electrolytes were made. No marked abnormalities of calcidiol2, calcidiol3, 24,25(OH)2D, or calcitriol were found in these patients, whose mean serum HCO3 was 18 +/- 3 mM/L (SD). Further, no relationship between serum HCO3 and calcitriol could be found. These results suggest that either vitamin D deficiency may be required before any alterations in the production of calcitriol are seen, or that the effects of acidosis in animals may not be reflected in humans. Further, it appears less likely that the bone disease found in renal tubular acidosis is related to abnormalities in vitamin D metabolism resulting from systemic acidosis, but that bone disease is more likely related to the acidosis and hypercalcuria prevalent in this disorder.     

Thalassemia B with distal renal tubular acidosis: a previously undescribed association

An infant with beta thalassemia major and distal renal tubular acidosis is described. Screening of forty patients with beta thalassemia major revealed no evidence of renal tubular acidosis. Although the possibility of coincidence cannot be completely excluded, we suggest that beta thalassemia major should be added to the list of conditions associated with distal renal tubular acidosis.     

Nephrotic Range Protienuria as a Presenting Feature of Classical Nephropathic Cystinosis

Patients with renal tubular acidosis (RTA) usually have tubular or low molecular weight proteinuria. The authors present a rare case of a 6-y-old girl with Fanconi syndrome secondary to cystinosis, who at presentation had nephrotic range proteinuria along with rickets and failure to thrive. Although hypoalbuminemia and massive proteinuria are characteristics of nephrotic syndrome, there are other conditions which can present with massive proteinuria.     

Renal tubular acidosis in a patient with recurrent metabolic alkalosis

A 7-month-old infant with failure to thrive and recurrent episodes of vomiting and metabolic alkalosis was evaluated. Urine pH, serum bicarbonate, and urine PCO2-blood PCO2 studies were consistent with the diagnosis of distal renal tubular acidosis (RTA-type I). Analysis of serum potassium and chloride levels during periods of alkalosis and acidosis revealed that potassium depletion and hypochloremic volume contraction served to maintain the alkalotic state despite the presence of an underlying chronic acidosis. This case represents an unusual presentation for renal tubular acidosis and suggests that, under certain conditions, renal tubular acidosis may predispose to the maintenance of a metabolic alkalosis.     

Renal handling of citrate in children with various kidney disorders

Citrate (CIT) excretion was measured in 24 h urine of children with various kidney disorders and controls. It was normal in urinary tract infection, idiopathic urolithiasis, and idiopathic hypercalciuria in the absence of renal dysfunction, but reduced in acute glomerulonephritis, distal renal tubular acidosis, and chronic renal failure. Increased citraturia was observed in cystinosis and in idiopathic de Toni-Debré-Fanconi syndrome. Renal handling of CIT was studied in 45 children with various chronic kidney disorders under standard inulin clearance conditions. CIT clearance correlated well with GFR above 50 ml/min/1.73 m2. At lower levels, percent tubular reabsorption of CIT decreased rapidly, reaching levels between 17% and 41% at GFR less than 10 ml/min/1.73 m2; this disproportionate fall might be related to reduced renal CIT utilization at a relatively early stage of renal insufficiency. During acid loading tests, citraturia was lowered, with a decrease of both urinary pH and plasma bicarbonate in tubular disorders and in controls. The lowest CIT excretion was measured in incomplete renal tubular acidosis with magnesium wasting. The findings are discussed in view of recent physiological data on renal metabolism of CIT.     

PROXIMAL RENAL TUBULAR ACIDOSIS IN VITAMIN D DEFICIENCY RICKETS

An 8-month-old girl presented with classical vitamin D deficiency rickets, secondary hyper-parathyroidism and hyperchloraemic acidosis. Renal acidification and bicarbonate titration studies showed the patient to have a proximal renal tubular acidosis. Rickets, secondary hy-perparathyroidism and proximal tubular acidosis were corrected by administration of calcium and vitamin D. A causal relationship between hyperparathyroidism and renal proximal tubular acidosis is suggested.     

Renal tubular acidosis: diagnostic work-up,treatment and mechanisms of growth retardation

Astute clinical observations, careful evaluation of laboratory results, together with research aimed at understanding the mechanisms of growth failure in children with the various types of renal tubular acidosis, have led to a more cogent approach to the management of children with renal tubular acidosis. This review examines the different clinical presentations of renal tubular acidosis, the diagnostic workup, the recent advances in our understanding of the mechanisms of growth failure and current therapeutic modalities.     

THE LOWE SYNDROME

Ion exchange chromatographic studies of the distribution of a number of amino acids in the body fluids of a two-year-old boy with the oculo-cerebro-renal syndrome are reported. Amino acid concentrations in serum and in cerebrospinal fluid were normal, whereas studies of the urine disclosed a highly selective (renal) aminoaciduria, rather similar to that occurring in healthy premature infants. Complementary observations on the acid-base metabolism served to establish the presence of renal tubular acidosis, probably due to a low tubular bicarbonate threshold. The implications of these findings are briefly discussed.     

Distal renal tubular acidosis with severe hypokalaemia, probably caused by colonic H(+)-K(+)-ATPase deficiency.

We describe a 21 month old male infant who presented with failure to thrive associated with severe hypokalaemia and metabolic acidosis, together with hypomagnesaemia. Evaluation revealed marked renal and probable faecal potassium wasting, distal renal tubular acidosis, mild urinary magnesium wasting, and a normal gastric pH (gastric H(+)-K(+)-ATPase). Hypokalaemic forms of metabolic acidosis, such as diabetic ketoacidosis and proximal renal tubular acidosis were ruled out from the clinical picture. The hypokalaemia of distal renal tubular acidosis usually improves with alkali therapy, but this was not observed: despite correction of acidosis with 5 mmol/kg potassium citrate per day, an additional 5 mmol/kg potassium chloride was required to bring serum potassium to 3.5 mmol/l. At 3 years of age potassium was provided in the absence of potential alkali and acidosis ensued; serum bicarbonate fell to 10 mmol/l. Although a specific genetic analysis is not yet possible, the abnormalities are consistent with a novel form of distal renal tubular acidosis. The pathophysiology probably does not stem from defects in the vacuolar H(+)-ATPase but more likely from deficient activity of the colonic isoform of H(+)-K(+)-ATPase that is resident in the medullary collecting duct and mediates potassium absorption and proton secretion.     

Distal renal tubular acidosis with severe hypokalaemia, probably caused by colonic H(+)-K(+)-ATPase deficiency

We describe a 21 month old male infant who presented with failure to thrive associated with severe hypokalaemia and metabolic acidosis, together with hypomagnesaemia. Evaluation revealed marked renal and probable faecal potassium wasting, distal renal tubular acidosis, mild urinary magnesium wasting, and a normal gastric pH (gastric H(+)-K(+)-ATPase). Hypokalaemic forms of metabolic acidosis, such as diabetic ketoacidosis and proximal renal tubular acidosis were ruled out from the clinical picture. The hypokalaemia of distal renal tubular acidosis usually improves with alkali therapy, but this was not observed: despite correction of acidosis with 5 mmol/kg potassium citrate per day, an additional 5 mmol/kg potassium chloride was required to bring serum potassium to 3.5 mmol/l. At 3 years of age potassium was provided in the absence of potential alkali and acidosis ensued; serum bicarbonate fell to 10 mmol/l. Although a specific genetic analysis is not yet possible, the abnormalities are consistent with a novel form of distal renal tubular acidosis. The pathophysiology probably does not stem from defects in the vacuolar H(+)-ATPase but more likely from deficient activity of the colonic isoform of H(+)-K(+)-ATPase that is resident in the medullary collecting duct and mediates potassium absorption and proton secretion.     

Prolidase deficiency and systemic lupus erythematosus

The case is reported of an infant with hyperammonaemia secondary to severe distal renal tubular acidosis. A clinical association between increased concentrations of ammonia in serum and renal tubular acidosis has not previously been described. In response to acidosis the infant's kidneys presumably increased ammonia synthesis but did not excrete ammonia, resulting in hyperammonaemia. The patient showed poor feeding, frequent vomiting, and failure to thrive, but did not have an inborn error of metabolism. This case report should alert doctors to consider renal tubular acidosis in the differential diagnosis of severely ill infants with metabolic acidosis and hyperammonaemia.     

The syndrome of renal tubular acidosis with nerve deafness.

Two brothers with renal tubular acidosis and nerve deafness are described. Studies of the physiopathological characteristics of the renal acidification defect show that the defect is limited to the distal tubule. Renal tubular acidosis with nerve deafness is a distinct nosologic entity that is determined by an autosomal recessive trait.     

THE SYNDROME OF RENAL TUBULAR ACIDOSIS WITH NERVE DEAFNESS

Abstract. Two brothers with renal tubular acidosis and nerve deafness are described. Studies of the physiopathological characteristics of the renal acidification defect show that the defect is limited to the distal tubule. Renal tubular acidosis with nerve deafness is a distinct nosologie entity that is determined by an autosomal recessive trait.