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At least 19 recordsLinked to original sources
PubMed1989

Nephrolithiasis in renal tubular acidosis.

Renal tubular acidosis is a term applied to several conditions in which metabolic acidosis is caused by specific defects in renal tubular hydrogen ion secretion. Three types of renal tubular acidosis generally are recognized based on the nature of the tubular defect. Nephrolithiasis occurs only in type I renal tubular acidosis, a condition marked by an abnormality in the generation and maintenance of a hydrogen ion gradient by the distal tubule. A forme fruste of type I renal tubular acidosis has been described in which the characteristic defect in distal hydrogen ion secretion occurs in the absence of metabolic acidosis (incomplete renal tubular acidosis). Type I renal tubular acidosis is a heterogeneous disorder that may be hereditary, idiopathic or secondary to a variety of conditions. Secondary type I renal tubular acidosis in sporadic cases is associated most commonly with autoimmune diseases, such as Sjögren's syndrome and systemic lupus erythematosus, and it occurs more frequently in women than men. Nephrolithiasis, which may occur in any of the subsets of type I renal tubular acidosis, accounts for most of the morbidity in adults and adolescents. Major risk factors for nephrolithiasis include alkaline urine, hypercalciuria and hypocitraturia. In addition, we found hyperuricosuria in 21 per cent of the patients with type I renal tubular acidosis with nephrolithiasis. The most frequently occurring risk factor, hypocitraturia, is due to decreased filtered load and/or to increased tubular reabsorption of filtered citrate. While increased tubular reabsorption may be due to systemic acidosis, hypocitraturia occurs in incomplete renal tubular acidosis. Furthermore, alkali therapy (either bicarbonate or citrate salts) increases citrate excretion in complete and incomplete type I renal tubular acidosis. These data suggest that hypocitraturia in type I renal tubular acidosis may be due to a defect in proximal tubule function. Hypercalciuria appears to have 2 causes. It may be due to metabolic acidosis, usually in children with a hereditary defect in urine acidification. In other cases familial idiopathic hypercalciuria causes nephrocalcinosis and nephrolithiasis resulting in distal tubular damage and type I renal tubular acidosis. In these latter cases hypercalciuria is present in complete and incomplete type I renal tubular acidosis. Potassium citrate appears to reduce calcium excretion in both types of hypercalciuric type I renal tubular acidosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Acidosis, Renal Tubular↗
PubMedDate not supplied

Renal tubular acidosis.

Renal tubular acidosis (RTA) is a form of metabolic acidosis due to abnormal alkali (bicarbonate) loss by the kidneys or their failure to excrete net acid. While the latter does occur in chronic renal failure, the term RTA is usually applied only when the glomerular filtration rate is normal or near normal. As well as a cause of metabolic acidosis, RTA often presents as renal stone disease with nephrocalcinosis, rickets/osteomalacia, and growth retardation in children. In this brief review, we have summarized the classification, clinical features and the underlying cell and molecular pathophysiology of RTA. However, despite significant advances in our understanding of the mechanisms of RTA, its treatment is still empirical and based largely on alkali replacement therapy; but its wider significance in renal stone and bone disease is becoming increasingly recognized.

Acidosis, Renal Tubular↗
PubMed1984

Idiopathic hypergammaglobulinaemia associated with nephrogenic diabetes insipidus and distal renal tubular acidosis.

Renal tubular dysfunction may be recognized in patients suffering from urinary light chain disease or non-myelomatous hypergammaglobulinaemia. We report a patient who has the combination of distal renal tubular acidosis and nephrogenic diabetes insipidus in association with hypergammaglobulinaemia due solely to increased IgG. We postulate that the abnormalities of distal nephron function resulted from cell-mediated immune damage.

Acidosis, Renal Tubular↗
PubMed1992

[Renal tubular acidosis].

Renal tubular acidosis (RTA) can be separated into three main types: distal RTA (the defect in the excretion of hydrogen ion), proximal RTA (the defect in the reabsorption of bicarbonate), and hyperkalemic RTA. Some patients present combined types of proximal and distal RTA. Most of the pediatric patients with RTA manifest failure to thrive. They have hyperchloremic metabolic acidosis and normal plasma anion gap. Fractional excretion of bicarbonate is below 5% in dRTA and over 15% in pRTA. Renal complications of dRTA are nephrocalcinosis, renal calculi, renal cysts and reversible low molecular weight proteinuria. The patient with isolated pRTA is very rare.

Acidosis, Renal Tubular↗
PubMed1999

Pregnancy and renal tubular acidosis.

Renal tubular acidosis (RTA) is uncommonly encountered in pregnancy. The risk for these women to develop pregnancy-induced hypertension has not been previously described. The renal defect noted in these women, aggravated by the normal hypervolemia of pregnancy, may predispose to hypertension. Three pregnancies in two women with RTA type 1 developed persistent diastolic hypertension in the third trimester. Mild renal insufficiency was noted in each woman as defined by serum creatinine of 0.9-1.1 and 1.4-1.6 mg/dL, respectively. Vaginal delivery was achieved in each without complications. Blood pressures returned to normal following each pregnancy. Pregnancy-induced hypertension developed in each of three pregnancies in two patients with RTA type 1. The risk for these women to develop pregnancy-induced hypertension may be associated with the higher reported risk in women with underlying renal disease.

Acidosis, Renal Tubular↗
PubMed1974

Renal tubular acidosis.

Renal tubular acidosis (RTA) is recognized to occur in several forms. Primary proximal RTA presents in infancy, almost exclusively in males, and is the only form of primary RTA that is transient. Distal RTA is encountered in familial and sporadic forms, the latter predominantly in females. A severe form of distal RTA in infancy, recently recognized, may represent still another type of the disease.

Acidosis, Renal Tubular↗
PubMed1990

Kearns-Sayre syndrome presenting as renal tubular acidosis.

Renal tubular acidosis and tetany were the 1st manifestations of Kearns-Sayre syndrome in a 5-year-old child. Subsequently, he developed progressive external ophthalmoplegia, ptosis, retinopathy, heart block, and endocrinopathy. There was a 7.5-kb deletion of mitochondrial DNA documented in muscle, kidney, skin fibroblasts, and leukocytes, providing evidence for a multisystem mitochondrial cytopathy.

Acidosis, Renal Tubular↗
PubMed1986

The clinical spectrum of renal tubular acidosis.

Renal tubular acidosis (RTA) is associated with a large group of disorders that interfere with normal tubular hydrogen-ion handling by any of several mechanisms. This review presents an approach to the pathophysiology, diagnosis, and therapy of RTA by defining three major subgroups: proximal RTA, distal RTA presenting with normal or decreased serum potassium (hypokalemic distal RTA), and distal RTA presenting with increased serum potassium (hyperkalemic distal RTA).

Acidosis, Renal Tubular↗
PubMed1990

Renal tubular acidosis.

Renal tubular acidosis refers to a group of disorders that result from pure tubular damage without concomitant glomerular damage. They could be hereditary (primary) or acquired (secondary to various disease states like sickle cell disease, obstructive uropathy, postrenal transplant, autoimmune disease, or drugs). The hallmark of the disorder is the presence of hyperchloremic metabolic acidosis with, or without, associated defects in potassium homeostasis, a UpH greater than 5.5 in the presence of systemic acidemia, and absence of an easily identifiable cause of the acidemia. There are three physiologic types whose basic defects are impairment of or a decrease in acid excretion, i.e., type 1 (dRTA); a failure in bicarbonate reabsorption, i.e., type 2 (pRTA); and deficiency of buffer or impaired generation of NH4+, i.e., type 4 RTA. Several pathophysiologic mechanisms have been postulated for these various types. pRTA is the least common of all in the adult population. It rarely occurs as an isolated defect. It is frequently accompanied by diffuse proximal tubule transport defects with aminoaciduria, glycosuria, hyperphosphaturia, and so forth (Fanconi syndrome). dRTA is associated with a high incidence of nephrolithiasis, nephrocalcinosis, osteodystrophy, and growth retardation (in children). Osteodystrophy also occurs in pRTA to a lesser degree and is believed to be secondary to hypophosphatemia. Patients with type 4 RTA usually have mild renal insufficiency from either diabetes mellitus or interstitial nephritis. Acute bicarbonate loading will result in a high fractional excretion of bicarbonate greater than 15% (FEHCO3- greater than 15%) in patients with pRTA, but FEHCO3- less than 3% in patients with dRTA. Type I patients will also have a low (U - B) PCO2 with bicarbonate loading. They are also unable to lower their urine pH to less than 5.5 with NH4Cl loading. The treatment of these patients involves avoidance of precipitating factors when possible, treatment of underlying disease, correction of electrolyte imbalance, particularly hypokalemia and hyperkalemia, and most importantly, the use of alkali. This will prevent or reduce all the various complications.

Acid-Base Equilibrium↗
PubMed1994

Renal stone risk factors in patients with type IV renal tubular acidosis.

Renal stone formation is uncommon in patients with type IV renal tubular acidosis (RTA). This study was undertaken to explore the urinary biochemical and physicochemical factors in patients with type IV RTA in order to elucidate the mechanisms that protect them from renal stone formation. Twelve subjects with type IV RTA and 12 matched subjects with a similar degree of kidney impairment but without RTA were studied. Both groups of patients had low urinary excretion of calcium, phosphorus, uric acid, and citrate, probably reflective of kidney impairment. Patients with type IV RTA had a significantly lower urinary pH and urinary excretion of calcium than their matched controls. Hypocitraturia was present in both groups without any significant difference between them. This study suggests that the major protection from renal stone formation in type IV RTA results from impaired renal function and ensuing reduction in renal excretion of stone-forming substances, such as calcium and uric acid.

Acidosis, Renal Tubular↗
PubMed1978

Renal histology and immunopathology in distal renal tubular acidosis.

Renal biospy studies are reported from 10 patients with distal renal tubular acidosis (DRTA). On the biopsies from 6 patients who had associated immunological abnormalities immunofluorescent studies for immunoglobulins, complement, and fibrin were performed. Interstitial cellular infiltration and fibrosis were common findings in patients with and without immunological abnormalities, and were usually associated with nephrocalcinosis and/or recurrent urinary infection. No immune deposits were demonstrated in association with the renal tubules. This study shows that DRTA in immunologically abnormal patients is not caused by tubular deposition of antibody or immune complexes. The possibility of cell mediated immune damage is discussed.

Acidosis, Renal Tubular↗
PubMed1996

Prevalence of endemic distal renal tubular acidosis and renal stone in the northeast of Thailand.

We have previously reported a large group of patients with endemic distal renal tubular acidosis (EdRTA) admitted to the hospitals in the northeast of Thailand. Since large number of patients were identified in a relatively short period of time, and in an area whose population is homogeneous, we were led to investigate the prevalence of the condition in the area. A survey was conducted in five villages (total population of 3,606) within the northeast of Thailand. 3,013 villagers were examined for urinary citrate concentration and short acid loading test was performed in those with low urinary citrate. 2.8% of the population (2.2-3.4%, 95% confidence interval) failed to lower their urine pH after acid loading; within this group, 0.8% of the population had serum potassium less than or equal to 3.5 mEq/l. In addition a large number of villagers were found to have low urinary citrate concentration and there was concurrent high prevalence of renal stone. The prevalence of EdRTA and renal stone was higher in villagers with poorer socioeconomic status, suggesting that environmental factors play a major role in their pathogenesis. Villagers with acidification defect have 2.4 times the chance of having renal stone and/or nephrocalcinosis. EdRTA is therefore one of the important factors responsible for the high prevalence of renal stone in the area. In conclusion we have confirmed the high prevalence of EdRTA in the northeast of Thailand and provided data showing high prevalence of renal stone and hypocitraturia in the same population.

Acidosis, Renal Tubular↗
PubMed1978

Bartter's syndrome presenting with features resembling renal tubular acidosis. Improvement of renal tubular defects by indomethacin.

A 2-year-old girl presenting with features of both Bartter's syndrome and renal tubular acidosis was investigated. Hypokalemia, increased plasma renin activity in the absence of hypertension, insensitivity to the pressor effects of angiotensin and a histological picture of juxtaglomerular hyperplasia were characteristic of Bartter's syndrome, but an unusual finding was the presence of metabolic acidosis instead of alkalosis. Functional studies revealed a proximal tubular defect in sodium and bicarbonate reabsorption and a distal defect in sodium reabsorption, urinary acidification and concentrating mechanism. Indomethacin administration was followed by an excellent clinical response and improvement of most functional abnormalities. The defect in distal sodium reabsorption was, however, not corrected by prostaglandin inhibition, and could represent the primary event leading to potassium wasting and secondary hypersecretion of prostaglandins.

Acidosis, Renal Tubular↗
PubMed2000

Renal tubular acidosis syndromes.

Renal tubular acidosis is a constellation of syndromes arising from different derangements of tubular acid transport. Recent advances in the biology of urinary acidification have allowed us to discern various molecular mechanisms responsible for these syndromes. This report relates clinical disorders of acidification to the underlying defective mechanisms responsible for them. A clinical classification of these disorders is presented, integrating each disorder with the prevailing serum potassium concentration. That renal tubular acidosis can be associated with low, normal, or high serum potassium concentration is now explainable by identifying the specific defect in transport causing each syndrome.

Acidosis, Renal Tubular↗
PubMed2001

Biochemical and genetic advances in distal renal tubular acidosis.

Distal renal tubular acidosis is a constellation of syndromes arising from different derangements of tubular acid transport. Recent advances in the biology of urinary acidification have allowed us to discern various molecular mechanisms responsible for these syndromes. This article relates clinical disorders of distal acidification to the underlying defective mechanisms responsible for them. A clinical classification of these disorders is presented which integrates each disorder with the prevailing serum potassium concentration. That distal renal tubular acidosis can be associated with low, normal, or high serum potassium concentration is now explainable by identifying the specific defect in transport causing each syndrome.

Acidosis, Renal Tubular↗
PubMed1985

Prevention of recurrent calcium stone formation with potassium citrate therapy in patients with distal renal tubular acidosis.

Distal renal tubular acidosis is a common cause of intractable calcium nephrolithiasis. We examined the effect of oral potassium citrate therapy in 9 patients with incomplete distal renal tubular acidosis diagnosed on the basis of an abnormal response to an oral ammonium chloride load. Patients were studied during a control phase and after 3 months of potassium citrate treatment (60 to 80 mEq. daily). Potassium citrate caused a significant increase in urinary pH and urinary citrate, and a decrease in urinary calcium. The urinary relative saturation ratio of calcium oxalate significantly decreased during treatment, while that of brushite did not change. Potassium citrate also was shown to inhibit new stone formation. During a mean treatment period of 34 months none of the 9 patients had new stones, although 39.3 plus or minus 79.7 (standard deviation) stones per patient formed during the 3 years preceding treatment. The results support the potential clinical advantage of potassium citrate therapy in patients with distal renal tubular acidosis and recurrent calcium nephrolithiasis.

Acidosis, Renal Tubular↗
PubMed1975

Proximal renal tubular acidosis in the tetralogy of fallot.

A 9-year-old girl presented with tetralogy of Fallot and moderate metabolic acidosis. Despite a Blalock's fistula there was evidence of chronic hypoxia with cyanosis, clubbing of fingers and toes and very elevated blood hematocrit values. Renal acidification and bicarbonate titration demonstrated the existence of proximal renal tubular acidosis: renal bicarbonate threshold was low (18 mmoles/1) and normal urinary acidificaiton was present at subthreshold serum bicarbonate levels. Following corrective heart surgery, blood acid-base values and renal reabsorption of bicarbonate became normal. A causal relationship between extracellular fluid volume expansion dependent on the high hematocrit and proximal renal tubular acidosis is suggested.

Acidosis, Renal Tubular↗
PubMed1984

Renal tubular acidosis in recurrent renal stone formers.

Renal tubular acidosis (RTA) is a well-known metabolic disturbance that may promote recurrent renal stone formation. However, its incidence, screening criteria and association with other lithogenic metabolic abnormalities are not established in recurrent nephrolithiasis. 10 of 50 consecutive recurrent renal stone formers had a persistent fasting morning urinary pH above 6.0 and/or a basal plasma bicarbonate concentration below 20.0 mM. Acid and alkaline loads disclosed RTA in 3 patients: 1 patient had incomplete type-1 distal RTA in addition to hyperoxaluria; a second patient showed complete type-2 proximal RTA, hyperoxaluria and renal hypercaliuria; and a third patient had incomplete proximal RTA without any other metabolic derangement. These results reinforce the importance of RTA as an isolated metabolic abnormality among recurrent renal stone formers. In addition, RTA appears to be more commonly associated with other lithogenic metabolic derangements than has been previously suspected. The extensive metabolic protocol used in this study provides a useful tool in the diagnosis and therapeutic considerations of recurrent nephrolithiasis.

Acidosis, Renal Tubular↗