scholarly journals Gut It Out: Laxative Abuse Mimicking Distal Renal Tubular Acidosis

2019 ◽  
Vol 44 (5) ◽  
pp. 1294-1299 ◽  
Author(s):  
Marius Sidler ◽  
Nilufar Mohebbi ◽  
Ewout J. Hoorn ◽  
Carsten A. Wagner
Keyword(s):  
Metabolic Acidosis ◽  
Renal Tubular Acidosis ◽  
Kidney Stones ◽  
Relative Number ◽  
Potassium Citrate ◽  
Distal Renal Tubular Acidosis ◽  
Anion Gap ◽  
Intercalated Cells ◽  
Laxative Abuse ◽  
Renal Tubular

Background: Distal renal tubular acidosis (dRTA) can be inherited or acquired. Case Presentation: Here, we describe the case of a 45-year-old female patient with non-anion gap metabolic acidosis, hypokalemia, and alkaline urine. She had a history of rheumatoid arthritis and kidney stones and failed to acidify urine upon the fludrocortisone and furosemide test. Therefore, the diagnosis of dRTA secondary to an autoimmune disease was made. A kidney biopsy was examined for markers of acid-secretory intercalated cells. Surprisingly, no obvious difference in the relative number of acid-secretory intercalated cells or in the distribution of major proteins involved in acid secretion was found. Furthermore, increasing doses of potassium citrate failed to correct the hypokalemia and acidosis. Since these findings were rather atypical for autoimmune dRTA, alternative causes of her hypokalemia and metabolic acidosis were sought. The patient was found to chronically consume laxatives, which can also cause kidney stones and may result in a false-positive urinary acidification test. Conclusion: Chronic laxative abuse may mimic dRTA and should therefore be considered in unexplained hypokalemia with non-anion gap metabolic acidosis.

Inherited Proximal and Distal Renal Tubular Acidosis

2017 ◽  
Author(s):  
Patricia Valles ◽  
Jesus Moran-Farias ◽  
Daniel Batlle
Keyword(s):  
Metabolic Acidosis ◽  
Renal Tubular Acidosis ◽  
Distal Renal Tubular Acidosis ◽  
Anion Gap ◽  
Intercalated Cells ◽  
Acid Excretion ◽  
Acid Base ◽  
Urine Ph ◽  
Renal Tubular ◽  
Net Acid Excretion

Acid-base homeostasis by the kidney is maintained through proximal tubular reclamation of filtered bicarbonate and the excretion of the daily acid load by collecting duct type A intercalated cells. The impairment of either process results in renal tubular acidosis (RTA), a group of disorders characterized by a reduced net acid excretion and a persistent hyperchloremic, non–anion gap metabolic acidosis. The primary or hereditary forms of proximal (pRTA) and distal renal tubular acidosis (dRTA) have received increased attention because of advances in the understanding of the molecular mechanism, whereby mutations in the main proteins involved in acid-base transport result in either reduced bicarbonate reabsorption or reduced H+ secretion and impaired acid excretion. dRTA is characterized by reduced net acid excretion and an inability to lower urine pH despite severe acidemia (but minimal HCO3– wastage). pRTA (type 2), by contrast, is characterized by marked HCO3– wastage but preserved ability to lower urine pH when plasma HCO3– (and therefore filtered HCO3–) is below a certain threshold. In children with dRTA, growth retardation caused by chronic metabolic acidosis is the key manifestation but is fully reversible with appropriate alkali therapy if initiated early in life. A striking manifestation of many patients with dRTA is the development of severe hypokalemia that may cause muscle paralysis. In this review, we discuss these types of hereditary RTA and the mechanisms involved in the genesis of these inherited tubular disorders. This review contains 5 figures, 1 table, and 103 references. Key words: Proximal renal tubular acidosis (pRTA), Distal renal tubular acidosis (dRTA), Hyperchloremic, non–anion gap metabolic acidosis, Hypokalemia, Fractional HCO3– excretion, Urinary gap, Fanconi Syndrome.ATP6V1B1 and ATP6V0A4 gene mutations . Intercalated cells ,

scholarly journals Metabolic acidosis in toluene sniffing

CJEM ◽  
2013 ◽  
Vol 15 (04) ◽  
pp. 249-252 ◽  
Author(s):  
Jon Tuchscherer ◽  
Habib Rehman
Keyword(s):  
Metabolic Acidosis ◽  
Renal Tubular Acidosis ◽  
Excretion Rate ◽  
Ammonia Excretion ◽  
Distal Renal Tubular Acidosis ◽  
Anion Gap ◽  
Renal Tubular ◽  
Conjugate Bases ◽  
Osmolal Gap ◽  
Ammonia Excretion Rate

ABSTRACT Toluene sniffing, frequently described under the generic category of “glue sniffing,” is a potential cause of normal anion gap metabolic acidosis due to distal renal tubular acidosis. Urine anion gap is used to diagnose metabolic acidosis of a normal anion gap variety; however, pitfalls exist when using urine anion gap in the setting of toluene sniffing. We present the case of a young woman who had a normal anion gap metabolic acidosis due to toluene sniffing and an unexpectedly low urine anion gap. In such a scenario, the urine anion gap will underestimate the rate of ammonia excretion when the conjugate bases of acids other than HCl are excreted in large quantities. Estimation of the urine osmolal gap will provide a more accurate ammonia excretion rate in these circumstances. The challenges in interpretation of the urine anion gap and ammonia excretion in the setting of distal renal tubular acidosis due to toluene toxicity are discussed.

Glue-sniffing and distal renal tubular acidosis: sticking to the facts.

1991 ◽  
Vol 1 (8) ◽  
pp. 1019-1027 ◽  
Author(s):  
E J Carlisle ◽  
S M Donnelly ◽  
S Vasuvattakul ◽  
K S Kamel ◽  
S Tobe ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
Renal Tubular Acidosis ◽  
Extracellular Fluid ◽  
Distal Renal Tubular Acidosis ◽  
Anion Gap ◽  
Acid Base ◽  
Major Question ◽  
The Subject ◽  
Renal Tubular ◽  
Sodium And Potassium

An index case is presented to introduce the subject of the acid-base and electrolyte abnormalities resulting from toluene abuse. These include metabolic acidosis associated with a normal anion gap and excessive loss of sodium and potassium in the urine. The major question addressed is, what is the basis for the metabolic acidosis? Overproduction of hippuric acid resulting from the metabolism of toluene plays a more important role in the genesis of the metabolic acidosis than was previously believed. This conclusion is supported by the observation that the rate of excretion of ammonium was not low during metabolic acidosis in six of eight patients, suggesting that distal renal tubular acidosis was not an important acid-base abnormality in most cases where ammonium was measured. The excretion of hippurate in the urine unmatched by ammonium also mandates an enhanced rate of excretion of the cations, sodium and potassium. The loss of sodium causes extracellular fluid volume contraction and a fall in the glomerular filtration rate, which may transform the normal anion gap type of metabolic acidosis into one with a high anion gap (accumulation of hippurate and other anions). Continuing loss of potassium in the urine leads to hypokalemia. An understanding of the metabolism of toluene provides the basis for the unusual biochemical abnormalities seen with abuse of this solvent.

scholarly journals Rickets with hypophosphatemia, hypokalemia and normal anion gap metabolic acidosis: not always an easy diagnosis

2020 ◽  
Vol 13 (1) ◽  
pp. e233350
Author(s):  
Saurav Shishir Agrawal ◽  
Chandan Kumar Mishra ◽  
Chhavi Agrawal ◽  
Partha Pratim Chakraborty
Keyword(s):  
Metabolic Acidosis ◽  
Renal Tubular Acidosis ◽  
Potassium Citrate ◽  
Anion Gap ◽  
Tubular Dysfunction ◽  
Diagnostic Challenge ◽  
Primary Defect ◽  
Proximal Tubular Dysfunction ◽  
Proximal Tubular ◽  
Renal Tubular

Rickets other than those associated with advanced kidney disease, isolated distal renal tubular acidosis (dRTA) and hypophosphatasia (defective tissue non-specific alkaline phosphatase) are associated with hypophosphatemia due to abnormal proximal tubular reabsorption of phosphate. dRTA, however, at times is associated with completely reversible proximal tubular dysfunction. On the other hand, severe hypophosphatemia of different aetiologies may also interfere with both distal tubular acid excretion and proximal tubular functions giving rise to transient secondary renal tubular acidosis (distal and/or proximal). Hypophosphatemia and non-anion gap metabolic acidosis thus pose a diagnostic challenge occasionally. A definitive diagnosis and an appropriate management of the primary defect results in complete reversal of the secondary abnormality. A child with vitamin D resistant rickets was thoroughly evaluated and found to have primary dRTA with secondary proximal tubular dysfunction in the form of phosphaturia and low molecular weight proteinuria. The child was treated only with oral potassium citrate. A complete clinical, biochemical and radiological improvement was noticed in follow-up.

P0058THE ROLE OF GENETICS IN INCOMPLETE DISTAL RENAL TUBULAR ACIDOSIS IN NEPHROLITHIASIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Viola D'Ambrosio ◽  
Eugenio Sangiorgi ◽  
Bernhard Hess ◽  
Giovanni Gambaro ◽  
Pietro Manuel Ferraro
Keyword(s):  
Metabolic Acidosis ◽  
Genetic Testing ◽  
Family History ◽  
Renal Tubular Acidosis ◽  
Kidney Stones ◽  
Distal Renal Tubular Acidosis ◽  
Urinary Acidification ◽  
Stone Formers ◽  
History Of ◽  
Renal Tubular

Abstract Background and Aims Distal renal tubular acidosis (dRTA) is characterized by an impairment of urinary acidification resulting in a hyperchloremic non-anion gap metabolic acidosis, hypokalemia and inappropriately elevated urine pH. If not treated, this chronic condition eventually leads to nephrocalcinosis and recurrent nephrolithiasis, impaired renal function and bone demineralization due to reabsorption of bicarbonate and phosphate complexed with calcium from the bone as a buffer for metabolic acidosis. Distal RTA is therefore a well-defined entity that can be diagnosed by genetic testing of five genes known to be disease-causative (ATPV1B1 and ATPV0A4, FOXi1, SLC4A1 and WDR72). Incomplete distal renal tubular acidosis (idRTA) is defined as impaired urinary acidification that does not lead to overt metabolic acidosis and therefore can be diagnosed if patients fail to adequately acidify urine after an ammonium chloride (NH4Cl) challenge or other acid load tests. It is observed in 10-20% of calcium stone formers. It is still uncertain whether idRTA represents a distinct entity or it is part of the dRTA spectrum and whether it is caused by mutations in the same genes of overt dRTA. Heterozygous ATP6V1B1 pathogenic variants have been linked to idRTA, as well as mutations in SLC4A1. Method In this cross-sectional study we investigated a group of 23 stone formers whose clinical features were suspicious of idRTA: a history of nephrolithiasis or nephrocalcinosis with morning urinary pH > 5.8 in the absence of overt metabolic acidosis. They therefore underwent a simplified NH4Cl challenge and were found to have impaired urinary acidification ability. These patients were then analyzed by genetic testing with sequencing of 4 genes: SLC4A1, ATP6V1B1, ATP6V0A4 and FOXi1. Results Two unrelated individuals were found to have mutations in SLC4A1: 2 different variants in heterozygosis that had never been described before. The first patient was a 47-year old man, recurrent stone former (mainly apatite, but also some calcium oxalate), with hypercalciuria but normal bone mineral density (BMD). His family history revealed 1 uncle with kidney stones. The second patient was a 56-year old woman with a diagnosis of osteogenesis imperfecta, a history of reduced BMD and severe restrictive ventilation disorder and passed 1 stone (35% apatite, 65% CaOx). She was found to have bilateral nephrocalcinosis and hypocitraturia. Her family history revealed a sister with kidney stones. Conversely, 21 patients did not show any mutations for the genes sequenced, leading to a prevalence of genetic mutations of 8.7%. This is a much lower figure compared with overt dRTA, in which only 30% of patients with a clinical diagnosis of hereditary dRTA have no identified causative mutations in the currently known genes. Conclusion This suggests the involvement of other genes (WDR72 or others) or non-genetic tubular dysfunction in the pathogenesis of idRTA in stone formers.

scholarly journals Acute Respiratory Failure Due to Hypokalaemic Muscular Paralysis from Renal Tubular Acidosis

2005 ◽  
Vol 33 (5) ◽  
pp. 656-658 ◽  
Author(s):  
S. Gombar ◽  
P. J. Mathew ◽  
K. K. Gombar ◽  
S. D'Cruz ◽  
G. Goyal
Keyword(s):  
Mechanical Ventilation ◽  
Metabolic Acidosis ◽  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
Renal Tubular Acidosis ◽  
Cardiac Arrhythmias ◽  
Distal Renal Tubular Acidosis ◽  
Life Threatening ◽  
Renal Tubular ◽  
Potassium Replacement

We report a case of hypokalaemic quadriplegia with acute respiratory failure and life-threatening cardiac arrhythmias in a 26-year-old woman who was diagnosed to have distal renal tubular acidosis. She had persistent metabolic acidosis with severe hypokalaemia and required mechanical ventilation and potassium replacement. The anaesthetic implications of renal tubular acidosis are also discussed.

Cyclosporin A produces distal renal tubular acidosis by blocking peptidyl prolyl cis-trans isomerase activity of cyclophilin

2005 ◽  
Vol 288 (1) ◽  
pp. F40-F47 ◽  
Author(s):  
Seiji Watanabe ◽  
Shuichi Tsuruoka ◽  
Soundarapandian Vijayakumar ◽  
Gunter Fischer ◽  
Yixin Zhang ◽  
...  
Keyword(s):  
Cyclosporin A ◽  
Renal Tubular Acidosis ◽  
Cyclophilin A ◽  
Distal Renal Tubular Acidosis ◽  
Apical Surface ◽  
Intercalated Cells ◽  
Ppiase Activity ◽  
Fk 506 ◽  
Isomerase Activity ◽  
Renal Tubular

Cyclosporin A (CsA), a widely used immunosuppressant, causes distal renal tubular acidosis (dRTA). It exerts its immunosuppressive effect by a calcineurin-inhibitory complex with its cytosolic receptor, cyclophilin A. However, CsA also inhibits the peptidyl prolyl cis-trans isomerase (PPIase) activity of cyclophilin A. We studied HCO3− transport and changes in β-intercalated cell pH on luminal Cl− removal in isolated, perfused rabbit cortical collecting tubules (CCDs) before and after exposure to media pH 6.8 for 3 h. Acid incubation causes adaptive changes in β-intercalated cells by extracellular deposition of hensin ( J Clin Invest 109: 89, 2002). Here, CsA prevented this adaptation. The unidirectional HCO3− secretory flux, estimated as the difference between net flux and that after Cl− removal from the lumen, was −6.7 ± 0.2 pmol·min−1·mm−1 and decreased to −1.3 ± 0.2 after acid incubation. CsA in the bath prevented the adaptive decreases in HCO3− secretion and apical Cl−:HCO3− exchange. To determine the mechanism, we incubated CCDs with FK-506, which inhibits calcineurin activity independently of the host cell cyclophilin. FK-506 did not prevent the acid-induced adaptive decrease in unidirectional HCO3− secretion. However, [AD-Ser]8 CsA, a CsA derivative, which does not inhibit calcineurin but inhibits PPIase activity of cyclophilin A, completely blocked the effect of acid incubation on apical Cl−:HCO3− exchange. Acid incubation resulted in prominent “clumpy” staining of extracellular hensin and diminished apical surface of β-intercalated cells [smaller peanut agglutinin (PNA) caps]. CsA and [AD-Ser]8 CsA prevented most hensin staining and the reduction of apical surface; PNA caps were more prominent. We suggest that hensin polymerization around adapting β-intercalated cells requires the PPIase activity of cyclophilins. Thus CsA is able to prevent this adaptation by inhibition of a peptidyl prolyl cis-trans isomerase activity. Such inhibition may cause dRTA during acid loading.

scholarly journals SUN-185 Severe Hyponatremia and Type 4 Renal Tubular Acidosis (Functional Hypoaldosteronism) Secondary to Trimethoprim

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Yun Qing Koh ◽  
Kian Ming Jeremy Hoe ◽  
Timothy Peng Lim Quek
Keyword(s):  
Metabolic Acidosis ◽  
Sodium Chloride ◽  
Sodium Bicarbonate ◽  
Renal Tubular Acidosis ◽  
Anion Gap ◽  
Aortic Graft ◽  
Acid Base ◽  
Severe Hyponatremia ◽  
Renal Tubular ◽  
Oral Sodium

Abstract Introduction: Trimethoprim-sulfamethoxazole (TMP-SMX) is a commonly used antibiotic. We present a case of severe hyponatremia and Type 4 renal tubular acidosis (functional hypoaldosteronism) in a patient treated with TMP-SMX. Clinical Case: A 62 year old gentleman with hypertension, dyslipidemia and a surgically repaired abdominal aortic aneurysm developed an aortic graft infection. He was admitted to hospital for acute right lower limb ischemia with embolic phenomena, and underwent surgical graft explantation. He required multiple courses of antibiotics post operatively. He was initially referred to Endocrinology for severe hyponatremia, deemed likely to be from a salt losing nephropathy secondary to polymyxin. Thyroid function and morning cortisol levels were normal. He was managed with intravenous hypertonic saline and oral salt tablets. The hyponatraemia resolved a week after polymyxin was stopped. Intravenous TMP-SMX was commenced the next day at 240 mg BD. A week later, the hyponatremia recurred, with concomitant hyperkalemia and a normal anion gap metabolic acidosis. The serum sodium was 126 mmol/L (reference interval (RI) 135-145) and the serum osmolality 275 mmol/kg (RI 275- 305). Urine studies showed a high urinary sodium (154 mmol/L) and osmolality (481 mmol/kg), consistent with renal salt wasting. The serum potassium rose to a peak of 6.1 mmol/L (RI 3.5 - 5.0), with a normal anion gap metabolic acidosis (bicarbonate 17 mmol/L (RI 21 – 31)). A paired urine pH of 8 pointed to an inability to acidify the urine. Given the clinical course and laboratory investigations, the diagnosis of TMP-associated hyponatremia and Type 4 RTA was made. Oral resonium was started to correct hyperkalemia, with a combination of oral sodium chloride and sodium bicarbonate used to treat the hyponatremia and metabolic acidosis. Fludrocortisone was not used given the concerns of causing hypertension in a patient with a diseased aortic graft. The dose of TMP-SMX was gradually reduced with improvement of the acid-base and electrolyte abnormalities, lending weight to our diagnosis. After the dose of the TMP-SMX was reduced to 80 mg BD, the hyperkalemia and metabolic acidosis resolved. The oral sodium chloride and sodium bicarbonate were gradually tailed off and stopped after cessation of the TMP-SMX. Clinical Lesson: Trimethoprim blocks the epithelial sodium channel (ENaC) of the principal cells in the terminal portion of the nephron, similar to potassium sparing diuretics like amiloride and triampterene. The resulting hyponatremia, hyperkalemia and metabolic acidosis can be life threatening. Therefore, monitoring of electrolytes and acid base status is important, particularly in susceptible patients or in those where a high dose of trimethoprim is required.

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