Acid-Base Disorders

2018 ◽  
Author(s):  
Aaron Skolnik ◽  
Jessica Monas

Under physiologic conditions, the acid-base balance of the body is maintained via changes in ventilation that eliminate carbon dioxide, buffering of acid loads, and renal excretion of hydrogen ions. Failure to maintain the pH of the blood between 7.35 and 7.45 can result in life-threatening conditions. This review details the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes of acid-base disorders. Figures show the relationship between hydrogen ions and blood pH, proximal tubular bicarbonate reabsorption, the secretion of hydrogen ions, renal ammonia production, ammonium diffusion, metabolic alkalosis, electrocardiographic changes in hypokalemia and hyperkalemia, pseudoinfarction caused by hyperkalemia, and an algorithmic approach to suspected acid-base disorders. Tables list causes of high–anion gap metabolic acidosis, metabolic acidosis with a normal anion gap, type 1 renal tubular acidosis, type 4 renal tubular acidosis and aldosterone resistance, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis; treatment of hyperkalemia; and a stepwise approach for the evaluation of suspected acid-base disorders. This review contains 9 highly rendered figures, 9 tables, 64 references, and a list of pertinent Web sites.

2015 ◽  
Author(s):  
Aaron Skolnik ◽  
Jessica Monas

Under physiologic conditions, the acid-base balance of the body is maintained via changes in ventilation that eliminate carbon dioxide, buffering of acid loads, and renal excretion of hydrogen ions. Failure to maintain the pH of the blood between 7.35 and 7.45 can result in life-threatening conditions. This review details the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes of acid-base disorders. Figures show the relationship between hydrogen ions and blood pH, proximal tubular bicarbonate reabsorption, the secretion of hydrogen ions, renal ammonia production, ammonium diffusion, metabolic alkalosis, electrocardiographic changes in hypokalemia and hyperkalemia, pseudoinfarction caused by hyperkalemia, and an algorithmic approach to suspected acid-base disorders. Tables list causes of high–anion gap metabolic acidosis, metabolic acidosis with a normal anion gap, type 1 renal tubular acidosis, type 4 renal tubular acidosis and aldosterone resistance, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis; treatment of hyperkalemia; and a stepwise approach for the evaluation of suspected acid-base disorders. This review contains 9 highly rendered figures, 9 tables, 64 references, and a list of pertinent Web sites.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Yun Qing Koh ◽  
Kian Ming Jeremy Hoe ◽  
Timothy Peng Lim Quek

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.


1991 ◽  
Vol 1 (8) ◽  
pp. 1019-1027 ◽  
Author(s):  
E J Carlisle ◽  
S M Donnelly ◽  
S Vasuvattakul ◽  
K S Kamel ◽  
S Tobe ◽  
...  

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.


2013 ◽  
Author(s):  
Ann P. O'Rourke ◽  
James Orr ◽  
Suresh Agarwal

Anticipation and early identification of conditions that alter the body's ability to compensate for acid-base disorders are vital in managing surgical patients. This review describes the general principles and classification of acid-base disorders. Metabolic acid-base disorders are presented, including metabolic acidosis and alkalosis. Respiratory acid-base disorders are also presented, including respiratory acidosis and alkalosis. Tables show the differentiation of acid-base disorders, causes of positive–anion gap acidosis, the differential diagnosis for normal–anion gap metabolic acidosis, the mechanisms associated with increased serum lactate concentration, and the differential diagnosis for metabolic alkalosis. This review contains 7 highly rendered figures, 5 tables, and 135 references.


2017 ◽  
Author(s):  
Patricia Valles ◽  
Jesus Moran-Farias ◽  
Daniel Batlle

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 ,


1987 ◽  
Vol 253 (3) ◽  
pp. G330-G335
Author(s):  
D. S. Goldfarb ◽  
P. M. Ingrassia ◽  
A. N. Charney

We previously reported that systemic pH and HCO3 concentration affect ileal water and electrolyte absorption. To determine whether these effects could influence an ongoing secretory process, we measured transport in ileal loops exposed to either saline or 50-75 micrograms cholera toxin in mechanically ventilated Sprague-Dawley rats anesthetized with pentobarbital sodium. The effects of acute respiratory and metabolic acidosis and alkalosis were then examined. Decreases in systemic pH during respiratory acidosis caused equivalent increases in net water (54 +/- 8 microliters . cm-1 . h-1) and Na absorption (7 +/- 1 mu eq . cm- . h-1) and smaller increases in Cl absorption in cholera toxin compared with saline loops. These increases reversed the net secretion of these ions observed during alkalemia in the cholera toxin loops to net absorption. Metabolic acidosis and alkalosis and respiratory compensation of systemic pH of these metabolic disorders also altered cholera toxin-induced secretion in a direction consistent with the pH change. The increase in net HCO3 secretion caused by cholera toxin was unaffected by the respiratory disorders and did not vary with the HCO3 concentration in the metabolic disorders. These findings suggest that the systemic acid-base disorders that characterize intestinal secretory states may themselves alter intestinal absorptive function and fluid losses.


CJEM ◽  
2013 ◽  
Vol 15 (04) ◽  
pp. 249-252 ◽  
Author(s):  
Jon Tuchscherer ◽  
Habib Rehman

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.


2015 ◽  
Vol 18 (1) ◽  
pp. 217-222 ◽  
Author(s):  
P. Sławuta ◽  
K. Glińska-Suchocka ◽  
A. Cekiera

AbstractApart from the HH equation, the acid-base balance of an organism is also described by the Stewart model, which assumes that the proper insight into the ABB of the organism is given by an analysis of: pCO2, the difference of concentrations of strong cations and anions in the blood serum – SID, and the total concentration of nonvolatile weak acids – Acid total. The notion of an anion gap (AG), or the apparent lack of ions, is closely related to the acid-base balance described according to the HH equation. Its value mainly consists of negatively charged proteins, phosphates, and sulphates in blood. In the human medicine, a modified anion gap is used, which, including the concentration of the protein buffer of blood, is, in fact, the combination of the apparent lack of ions derived from the classic model and the Stewart model. In brachycephalic dogs, respiratory acidosis often occurs, which is caused by an overgrowth of the soft palate, making it impossible for a free air flow and causing an increase in pCO2– carbonic acid anhydride The aim of the present paper was an attempt to answer the question whether, in the case of systemic respiratory acidosis, changes in the concentration of buffering ions can also be seen. The study was carried out on 60 adult dogs of boxer breed in which, on the basis of the results of endoscopic examination, a strong overgrowth of the soft palate requiring a surgical correction was found. For each dog, the value of the anion gap before and after the palate correction procedure was calculated according to the following equation: AG = ([Na+mmol/l] + [K+mmol/l]) – ([Cl−mmol/l]+[HCO3−mmol/l]) as well as the value of the modified AG – according to the following equation: AGm= calculated AG + 2.5 × (albuminsr– albuminsd). The values of AG calculated for the dogs before and after the procedure fell within the limits of the reference values and did not differ significantly whereas the values of AGmcalculated for the dogs before and after the procedure differed from each other significantly. Conclusions: 1) On the basis of the values of AGmobtained it should be stated that in spite of finding respiratory acidosis in the examined dogs, changes in ion concentration can also be seen, which, according to the Stewart theory, compensate metabolic ABB disorders 2) In spite of the fact that all the values used for calculation of AGmwere within the limits of reference values, the values of AGmin dogs before and after the soft palate correction procedure differed from each other significantly, which proves high sensitivity and usefulness of the AGmcalculation as a diagnostic method.


2018 ◽  
Vol 1 (1) ◽  
pp. 21-25
Author(s):  
Raymond Azar ◽  
Vincent Coevoet

Acid-base status of patients on peritoneal dialysis is influenced by multiple factors. Metabolic acidosis is a common feature of chronic renal failure and dialysis treatment provides alkali in the dialysate in order to maintain a normal acid-base balance. This paper reports the prevalence of acid-base disorders in peritoneal dialysis patients and their associations with clinical and laboratory parameters. This is a cross-sectional retrospective study that included all PD patients registered in the RDPLF database. Metabolic acidosis was found in 20.4% of patients while 27.8% of patients had metabolic alkalosis. There is a significant relationship between age, protein intake estimated by nPNA and the level of alkaline reserve pleading in favor of the influence of dietary intakes in the maintenance of metabolic acidosis. Low residual renal function is associated with a lower probability of being in metabolic alkalosis. These results could allow an individual choice of the dialysate buffer in order to permanently obtain stable acid-base status in patients on peritoneal dialysis.


1982 ◽  
Vol 243 (4) ◽  
pp. F335-F341 ◽  
Author(s):  
M. S. Lucci ◽  
L. R. Pucacco ◽  
N. W. Carter ◽  
T. D. DuBose

Previous micropuncture studies utilizing indirect methods to estimate bicarbonate transport in the rat superficial distal tubule have indicated that the distal bicarbonate reabsorptive process normally operates well below the saturation level. Recent studies from our laboratory failed to demonstrate a spontaneous acid disequilibrium pH in this segment, implying that the bicarbonate reabsorptive rate was less than previously estimated. The purpose of the present experiments were 1) to measure the rate of absolute bicarbonate reabsorption by the rat superficial distal tubule while controlling bicarbonate delivery, and 2) to examine the effects of alterations in acid-base status on the rate of bicarbonate reabsorption. Five groups of rats in different states of acid-base balance were studied. No significant bicarbonate reabsorption was detected in the control hydropenic, combined respiratory acidosis-metabolic alkalosis, acute respiratory acidosis, or acute metabolic acidosis groups. In contrast, metabolic acidosis of 3 days duration resulted in a significant bicarbonate reabsorptive rate of 52.6 +/- 13.9 pmol . mm-1 . min-1. The observation of significant bicarbonate reabsorption in the distal tubule only during chronic metabolic acidosis of 3 days duration is compatible with adaptation of this normally low-capacity segment to chronic changes in systemic acid-base states.


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