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A case of active acromegaly with reduced height and type 1 renal tubular acidosis.

A 41-year-old man with acromegaly was suffering from chronic, progressive backache and aware of reduction in his body height. Endocrine studies revealed increased glucose non-suppressible serum growth hormone (GH) and serum prolactin (PRL). Pituitary microadenoma was detected by a computerized axial tomogram and subsequently resected by trans-sphenoidal adenomectomy. The tumor proved to be a mixed GH- and PRL-secreting adenoma by electron microscopy and immunoperoxidase staining. Concurrent investigation of backache and reduced height disclosed markedly reduced radiodensity of the spinal bones, bilateral nephrocalcinosis, and hypercalciuria, which were ascribed to renal tubular acidosis (RTA) demonstrated by reduced urinary excretion of acids and insufficient reduction of urinary pH following oral administration of ammonium chloride. From the analogy to certain endocrinopathies, it appears likely that enhanced calcium metabolism and resultant hypercalciuria due to excess GH and PRL have led to the development of RTA, which further enhanced calciuria. Such enhanced calcium metabolism and consequent hypercalicuria conceivably led to accelerated demineralization of the spine and resulted in the reduced height of this patient in his early forties.

Acidosis, Renal Tubular↗

Proximal renal tubular acidosis: association with familial normaldosteronemic hyperpotassemia and hypertension.

Further investigation of a family with normaldosteronemic hyperpotassemia and low-renin hypertension showed seven members from three generations, who ranged in age from 4 to 56 years, to be affected. Results of earlier studies had established a normally functioning renin-aldosterone system and normal renal handling of potassium. Constant, albeit mild and asymptomatic, metabolic acidosis in all those affected prompted bicarbonate loading in both the propositus and his brother, which revealed a maximal renal tubular excretory capacity for bicarbonate reabsorption at serum levels of 18 mmole/liter and proved proximal renal tubular acidosis (PRTA). Further, a linear increase in urinary fractional potassium excretion accompanied that of bicarbonate in both, as in normal individuals. Dextrose-insulin infusion in the brother failed to reduce hyperpotassemia. These data support the hypothesis that a generalized cell membrane defect that specifically impedes potassium influx (as opposed to an isolated renal tubular defect) underlies this autosomal dominant disorder.

Acidosis, Renal Tubular↗

[A case of Sjögren's syndrome complicated with cryoglobulinemia, nephrogenic diabetes insipidus, and renal tubular acidosis].

A 68-year-old woman had been complained of xerostomia since she was 30 years old. Further symptoms of polyuria, polyposia and insomnia had been developed since she was 35 years old. The biopsy material from a minor salivary gland demonstrated the infiltration of lymphocytes into mesenchyme which was compatible with Sjögren's syndrome. She admitted to our hospital because of myalgia in bilateral gastrocnemius and petechiae in both lower extremities in addition to the complaints described above. Complete blood cell counts on admission revealed hemoglobin 9.7 g/dl, platelet count 12.5 x 10(4)/microliters, and white blood cell count 3,300/microliters. Marked polyuria, polyposia (more than 5,000 ml/day, respectively) and low urine gravity (1.005) were observed, although the serum creatinine level showed normal value. Serologic examination showed that the elevation of total serum protein concentration (9.5 g/dl) with marked elevation of serum IgG level (6,190 mg/dl). Her immunoglobulins contained cryoglobulin (cryocrit 20%), and immunoelectrophoresis demonstrated the existence of IgG-kappa monoclonal protein. A positive anti-nuclear antibody at 1:320 dilution, a positive rheumatoid factor and a positive antibody to SS-A (Ro) were also observed. The serial studies of blood gas analysis could not demonstrated the presence of metabolic acidosis. Together with the result of elevated plasma antidiuretic hormone level and results of vasopressin test, Fishberg's concentrating test and the tests of the overload of NH4Cl or bicarbonate, she was diagnosed Sjögren's syndrome with both diabetes insipidus and subclinical renal tubular acidosis. She was initially medicated with prednisolone (40 mg/day, orally), then she was given six courses of intravenous cyclophosphamide (750 mg/body/month).(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗

Severe hereditary spherocytosis and distal renal tubular acidosis associated with the total absence of band 3.

Absence of band 3, associated with the mutation Coimbra (V488M) in the homozygous state, caused severe hereditary spherocytosis in a young child. Although prenatal testing was made available to the parents, it was declined. Because the fetus stopped moving near term, an emergency cesarean section was performed and a severely anemic, hydropic female baby was delivered. She was resuscitated and initially kept alive with respiratory assistance and hypertransfusion therapy. Cord blood smears revealed erythroblastosis, poikilocytosis, and red cells with stalk-like elongations. Band 3 and protein 4.2 were absent; spectrin, ankyrin, and glycophorin A were significantly reduced. Renal tubular acidosis was detected by the age of 3 months. Nephrocalcinosis appeared soon thereafter. After 3 years of follow-up the child is doing reasonably well on a regimen that includes regular blood transfusions and daily bicarbonate supplements. The long-term prognosis remains uncertain given the potential for hematologic and renal complications. (Blood. 2000;96:1602-1604)

Acidosis, Renal Tubular↗

Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4.

Hearing depends on a high K(+) concentration bathing the apical membranes of sensory hair cells. K(+) that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media(). K(+) probably exits outer hair cells by KCNQ4 K(+) channels(), and is then transported by means of a gap junction system connecting supporting Deiters' cells and fibrocytes() back to the stria vascularis. We show here that mice lacking the K(+)/Cl(-) (K-Cl) co-transporter Kcc4 (coded for by Slc12a7) are deaf because their hair cells degenerate rapidly after the beginning of hearing. In the mature organ of Corti, Kcc4 is restricted to supporting cells of outer and inner hair cells. Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway. Similar to some human genetic syndromes(), deafness in Kcc4-deficient mice is associated with renal tubular acidosis. It probably results from an impairment of Cl(-) recycling across the basolateral membrane of acid-secreting alpha-intercalated cells of the distal nephron.

Acidosis, Renal Tubular↗

[Renal tubular acidosis (type 2) in a Friesian mare].

A 2-year-old Friesian mare was examined because she had been sluggish for a few weeks. Blood biochemistry showed that concentrations of creatinine (136 mumol.L-1) and urea nitrogen (6.1 mmol.L-1) in plasma were within their normal limits. Severe metabolic acidosis was apparent; the venous pH was 7.154 and the bicarbonate concentration was 13 mmol.L-1. The base excess amounted to -15.3 mmol.L-1 and the venous pCO2 measured 5.1 kPa. Plasma sodium was normal (135 mmol.L-1) and plasma chloride (113 mmol.L-1) was slightly elevated, but there was a hypokalaemia (2.9 mmol.L-1). The urine had a specific gravity of 1.040 and a pH of 5. These findings indicated type 2 renal tubular acidosis. The blood values returned to normal 3 days after treatment with sodium bicarbonate as a 4.2 per cent solution (3.2 mol in total) and additional bicarbonate (125 g) and potassium chloride (100 g) administered orally.

Acidosis, Renal Tubular↗

Molecular cloning and characterization of novel tissue-specific isoforms of the human vacuolar H(+)-ATPase C, G and d subunits, and their evaluation in autosomal recessive distal renal tubular acidosis.

Several of the 13 subunits comprising mammalian H(+)-ATPases have multiple isoforms, encoded by separate genes and with differing tissue expression patterns, which may play an important role in the intracellular localization and activity of H(+)-ATPases. Here we report the cloning of three previously uncharacterized human genes, ATP6V1C2, ATP6V1G3 and ATP6V0D2, encoding novel H(+)-ATPase subunit isoforms C2, G3 and d2, respectively. We demonstrate that these novel genes are expressed in kidney and few other tissues, and confirm previous reports that the C1, G1 and d1 isoforms are ubiquitously expressed, while G2 is brain-specific. Previously we have shown that mutations in two kidney-specific genes, ATP6V1B1 and ATP6V0A4, encoding the H(+)-ATPase B1 and a4 subunit isoforms, cause recessive distal renal tubular acidosis (dRTA). As the genes reported here are expressed mainly in kidney, we assessed their candidacy as causative genes for recessive dRTA in eight kindreds unlinked to either known disease locus. Although no potential disease-causing mutations were seen in this cohort, this does not rule out a role for these genes in other families. The identification of these three novel tissue-specific isoforms supports the hypothesis that subunit differences may play a key role in the structure, site and function of H(+)-ATPases within the cell.

Acidosis, Renal Tubular↗

Microperfusion study of proximal tubule bicarbonate transport in maleic acid-induced renal tubular acidosis.

Microperfusion studies were carried out in rats to examine the abnormality in proximal tubule HCO3- transport caused by maleic acid administration. Permeability of the proximal tubule to HCO-3 was measured by perfusing proximal tubules with a HCO3- -free low-buffer isotonic equilibrium solution containing acetazolamide after plasma [HCO3-] had been raised by intravenous NaHCO3 infusion. Insulin recovery in the collected perfusate was approximately 100% in control and maleic acid-treated rats. CO2 influx measured by microcalorimetry was not significantly different in control vs. maleic acid-treated rats. Thus maleic acid did not cause increased permeability of the proximal tubule to either inulin or HCO3-. In a second group of experiments, proximal tubule fluid and HCO3- efflux were measured in paired-reperfusion experiments before and after maleic acid administration. The perfusion fluid contained 25 mM HCO3- and 120 mM Cl-. HCO3- absorption was inhibited 25% (79 pmol/min), Na+ was inhibited 22% (164 pmol/min), and Cl- absorption (calculated as the anion gap) by 85 pmol/min. [HCO3-] in the collected perfusate rose significantly after maleic acid, presumably accompanied by a fall in [Cl-]. The observations indicate that proximal renal tubular acidosis (RTA) induced by maleic acid is characterized by impaired lumen-to-blood transport of sodium bicarbonate and chloride but not by increased backflux. Based on previously demonstrated effects of maleic acid on mitochondrial energy metabolism and cellular ATP levels, we postulate that the principal transport abnormality is impaired basolateral membrane active sodium transport, leading to a secondary reduction in brush border Na+-H+ exchange.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗

Renal Tubular Acidosis after Jejunoileal Bypass for Morbid Obesity: role of secondary hyperparathyroidism.

The effect of calcium infusion was studied in patients with renal tubular acidosis (RTA) and secondary hyperparathyroidism. Both developed after jejunoileal bypass operation (JIB) for morbid obesity. In three of four cases the acidification defect was abolished, probably due to a decrease of serum parathyroid hormone. As we found RTA in 9% (95% confidence limits 2-21%) of our patients, screening for acidosis is recommended in obesity patients after malabsorptive operations. RTA can be verified through an ammonium loading test. Before deciding on re-establishing bowel continuity due to RTA, we suggest that patients be evaluated for secondary hyperparathyroidism and vitamin D deficiency by measurement of serum calcium, parathyroid hormone and vitamin 1.25(OH)&inf2D&inf3;, and any calcium and vitamin D deficiency be corrected. An intravenous calcium loading test can predict the outcome of oral calcium and vitamin D supplementation. If RTA can be abolished through correction of calcium homeostasis, reoperation may be avoided. Before deciding on re-establishing bowel continuity in JIB patients with RTA, we therefore suggest that patients be evaluated for secondary hyperparathyroidism and any calcium deficiency be corrected.

Journal Article↗

[Distal renal tubular acidosis as a cause of osteomalacia in a patient with primary Sjögren's syndrome].

BACKGROUND: One half of the patients with primary Sjögren's syndrome has extraglandular manifestations, including renal involvement. The most frequent renal lesion is tubulo-interstitial nephritis, which manifests clinically as distal tubular acidosis and may result in the development of osteomalacia. CASE REPORT: In a 29-year-old female patient, with bilateral nephrolithiasis, the diagnosis of primary Sjögren's syndrome, tubulo-interstitial nephritis, distal renal tubular acidosis, and hypokalemia were established. She was treated for hypokalemia. Two years later she developed bone pains and muscle weakness, she wasn't able to walk, her proximal muscles and pelvic bones were painful, with radiological signs of pelvic bones osteopenia and pubic bones fractures. The diagnosis of osteomalacia was established and the treatment started with Schol's solution, vitamin D and calcium. In the following two months, acidosis was corrected, and the patient started walking. CONCLUSION: In our patient with primary Sjögren's syndrome and interstitial nephritis, osteomalacia was a result of the long time decompensate acidosis, so the correction of acidosis, and the supplementation of vitamin D and calcium were the integral part of the therapy.

Acidosis, Renal Tubular↗

Bilateral total ureteric bypass in the management of renal tubular acidosis.

Nephrocalcinosis and the subsequent obstruction of the ureters by urinary calculi can be a major problem in the management of a patient with renal tubular acidosis. We describe the case history of a girl with this condition in whom the interposition of segments of ileum between the kidneys and bladder, thus bypassing the ureters, had been used in an attempt to overcome the problem of recurrent ureteric obstruction by calculi.

Acute Kidney Injury↗

H-K-ATPase in distal renal tubular acidosis: urinary tract obstruction, lithium, and amiloride.

In previous studies we suggested that urinary tract obstruction and chronic administration of lithium or amiloride were models of "voltage-dependent" distal renal tubular acidosis (DRTA). Subsequently, differences among these three models suggested that the pathogenesis was far more complex than we originally proposed. A recent study showed that H-adenosinetriphosphatase (H-ATPase) activity was decreased in all three experimental models. In the current experiments we examined the effect of 24-h unilateral ureteral obstruction (UUO) and chronic administration of amiloride and lithium on collecting tubule H-K-ATPase, the other renal H-ATPase enzyme. In the obstructed kidney, cortical collecting tubule (CCT) H-K-ATPase activity was enhanced by 73 +/- 10.0%, whereas the enzyme activity in medullary collecting tubule (MCT) was decreased by 67 +/- 5.4%. In the normal contralateral kidney, activities of H-ATPase, H-K-ATPase, and Na-K-ATPase were increased by approximately 30% in both CCT and MCT. Following amiloride (3 mg.kg-1.day-1 x 3 days ip), rats had normal acid-base status, slight hyperkalemia, and markedly elevated plasma aldosterone levels. Both CCT and MCT H-K-ATPase activities in amiloride-treated rats were unchanged. After LiCl (4 meq.kg-1.day-1 x 3 days ip), rats developed mild metabolic acidosis and had normokalemia and normal aldosterone status. CCT H-K-ATPase activity in lithium-treated rats was decreased by 64 +/- 8.8%, whereas the enzyme activity in MCT remained unchanged. Lithium in vitro (30 meq/l) inhibited CCT, but not MCT, H-K-ATPase activity, whereas amiloride had no effect on the enzyme activity. (ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗

[A case of nephrocalcinosis due to Sjögren syndrome associated with renal tubular acidosis].

A 39-year-old women was admitted to the hospital because of fever, lumbago and recurrent history of spontaneous stone discharge. An abdominal X-ray film demonstrated multiple calculi in the medullary positions of both kidneys and right multiple ureteral stones. Laboratory examinations showed hypergammaglobulinemia and the urine pH level was fixed around 7; nevertheless general metabolic acidosis existed. These laboratory data indicated nephrocalcinosis due to Sjögren syndrome associated with renal tubular acidosis. Right multiple ureteral stones were removed by transurethral ureteroscopy. After starting alkali therapy, neither increased nor recurrent stone formation was recognized.

Acute Kidney Injury↗

[Distal renal tubular acidosis and nephrolithiasis in 3 cases of primary Sjögren syndrome].

Tubulo interstitial nephritis, the main manifestation of renal involvement in Sjögren syndrome, may lead to a tubular dysfunction that is usually subclinical. We report three women, aged 32, 35 and 35 years old, with a primary Sjögren syndrome and symptomatic type I or distal tubular acidosis. Two patients had nephrolithiasis and one a nephrocalcinosis. Two had a basal hyperchloremic metabolic acidosis. The ammonium chloride acidification test was abnormal in all, demonstrating a distal tubular defect. None had proximal tubular dysfunction. All had an urinary pH over 6.5 and hypocitraturia and none had hypercalciuria. Renal calculi were composed of calcium oxalate and calcium phosphate in two patients and calcium phosphate and ammonium phosphate in the other. All women had positive antinuclear antibodies with mottled pattern, two had anti Ro antibodies and positive rheumatoid factor and one had hypergammaglobulinemia. None had anti La antibodies, crioglobulinemia or monoclonal proteins.

Acidosis, Renal Tubular↗

Proximal renal tubular acidosis in metachromatic leukodystrophy.

A 2-year-old girl affected with the late infantile form of metachromatic leukodystrophy had a persistent and moderate metabolic acidosis. Renal functional studies demonstrated the presence of decreased tubular reabsorption of sodium, bicarbonate and some amino acids. Other tubular functions, including distal urinary acidification and concentrating mechanism were normal. Glomerular filtration rate was moderately decreased. Metachromatic inclusions were demonstrated along the nephron by histochemistry and electron microscopy. Tubular dysfunction in metachromatic leukodystrophy could have been overlooked until now given the severity of the neurological picture.

Acidosis, Renal Tubular↗

[Investigations on the pathogenesis of distal renal tubular acidosis (author's transl)].

In distal (type 1) RTA, renal acid excretion is impaired by the inability to establish adequate pH gradients between plasma and distal tubular fluid at any level of acidosis. Main clinical signs in infancy are anorexia, vomiting and failure to thrive. Despite low serum bicarbonate levels the renal threshold of bicarbonate is normal, while urinary pH levels are high even with values below the threshold. Under conditions of bicarbonate-induced systemic alkalosis urinary the pCO2 exceeds blood pCO2 in normal subjects. by contrast, the urinary pCO2 tension is not significantly greater in distal RTA, indicating a failure of the cells of the distal nephron to secrete hydrogen ions even without a gradient. Red cell carbonic anhydrase is within the normal range, whilst the inhibition of carbonic anhydrase activity has no effect on distal tubular function. Until now no histological or enzymatic defect could be detected to explain the ineffective acidification. Bicarbonate loading is followed by a lowering of calcium excretion to within the normal range and a decrease in the uncharacteristic renal hyperaminoaciduria.

Acidosis, Renal Tubular↗

Suspected renal tubular acidosis in two dogs.

Clinical signs of hyperventilation, muscle weakness and lethargy were recognised in a one-year-old female Bichon Frise and a three-year-old male Poodle. One dog was also hyperexcitable and pyrexic. The diagnosis of renal tubular acidosis was confirmed by demonstrating the tendency to an elevated urine pH, a low blood pH and low blood bicarbonate level, and by eliminating other causes of metabolic acidosis. Both dogs were treated with oral sodium bicarbonate resulting in improvement in their clinical condition and a return to near normal blood pH and bicarbonate levels.

Journal Article↗

Arthrogryposis, renal tubular acidosis and cholestasis (ARC) syndrome: two new cases and review.

ARC syndrome, the association of arthrogryposis, renal tubular dysfunction and cholestasis, is a rare genetic disorder. We report two Saudi infants from two different families with ARC syndrome. Magnetic resonance imaging of the brain of one of the infants showed lissencephaly, a previously unreported finding in this syndrome. We also review 39 ARC cases reported in the literature using the Medline database from January 1966 to September 2004.

Abnormalities, Multiple↗