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PubMed1978

Hyperchloremic metabolic acidosis in diabetes mellitus: a case report and discussion of pathophysiologic mechanisms.

A 21-year old woman with poorly controlled diabetes mellitus was examined for persistent hyperchloremic metabolic acidosis. There was no evidence of ingestion of hydrochloric acid or its equivalent. Gastrointestinal loss of bicarbonate was absent. Proximal tubular bicarbonate reabsorption and distal nephron hydrogen-ion secretion were normal. Ammonia and net acid excretions were high, and thus there was no obvious cause for this acidosis. Further study revealed a very large loss of beta-hydroxybutyrate in the urine that closely approximated net acid excretion. This loss of potential bicarbonate was the principal cause for the hyperchloremic metabolic acidosis. Phosphate, urate, and beta-hydroxybutyrate fractional excretions were all abnormally high. Generalized aminoaciduria was also present, but the renal handling of glucose and bicarbonate was normal. With improved control of her diabetes, the generalized aminoaciduria disappeared, the urine beta-hydroxybutyrate loss ceased, the fractional excretions of phosphate and urate approached normal, and the acidosis was rapidly corrected.

Adult↗
PubMed1976

[The value of alkalizing treatments in severe diabetic keto-acidosis].

In 37 diabetic patients with severe acidosis (pH less than 7.0; [HCO3-] less than 5.0 mMol/l), administration of insulin was preceded by a rapid infusion of molar sodium bicarbonate in order to obtain partial correction of acidosis (pH approximately 7.20). 31 patients survived (83,8%); 6 patients died in cardio-circulatory failure associated in two cases with acute pulmonary edema. Initial administration of bicarbonate appears to be beneficial in preventing the deleterious effects of prolonged severe acidosis, such as cardiac arrhythmias, shock or acute pulmonary edema. Furthermore, partial correction of acidosis decreases the total dose of insulin necessary to compensate hyperglycemia and thereby reduces the danger of late hypoglycemia. This treatment calls for frequent checks on acid-base status and serum potassium. In most cases hypokalemia develops, but can be easily corrected by administration of potassium chloride. Normalization of arterial pH by bicarbonate infusion is not recommended in view of the development of late hypernatremia and metabolic alkalosis.

Acid-Base Equilibrium↗
PubMed2026

Whole exome sequencing identifies three novel variants and establishes the molecular diagnosis of ATP6V0A4-related distal renal tubular acidosis in a lebanese infant.

BACKGROUND: Distal renal tubular acidosis (dRTA) is a rare inherited disorder characterized by impaired urinary acidification, leading to metabolic acidosis, hypokalemia, nephrocalcinosis, and growth impairment. Pathogenic variants in ATP6V0A4 are among the most common genetic causes of autosomal recessive dRTA. METHODS AND RESULTS: We report a Lebanese infant presenting with failure to thrive, recurrent vomiting, severe hyperchloremic metabolic acidosis, hypokalemia, and bilateral nephrocalcinosis, in whom whole-exome sequencing (WES) was performed to establish the molecular diagnosis and perform a comprehensive genomic evaluation. WES identified three novel variants, including a novel homozygous likely pathogenic ATP6V0A4 variant, consistent with the patient's phenotype. Two additional novel variants in TTN and CEP290 were also detected. Family segregation analysis confirmed the inheritance pattern of all three variants and refined the interpretation of the additional genomic findings. The patient showed sustained clinical and biochemical improvement to alkali therapy, with normalization of biochemical abnormalities and improvement in growth during follow-up. CONCLUSIONS: This report expands the molecular spectrum of ATP6V0A4-related dRTA and illustrates the clinical utility of comprehensive WES combined with segregation analysis for accurate molecular diagnosis, variant interpretation, genetic counseling, and the evaluation of additional genomic findings in rare inherited disorders.

Humans↗
PubMed1983

Lactic acidosis in severe asthma.

Twelve patients with severe asthma in whom lactic acidosis developed are presented. All had an arterial blood pH level lower than that expected for the measured partial pressure of arterial carbon dioxide, all had an abnormally large anion gap, and the blood lactate level exceeded 2.8 mmol/liter. Respiratory acidosis subsequently developed in eight patients, and six required intubation. Lactic acidosis can develop in patients with severe asthma. Such patients are in danger of the development of respiratory failure and must be treated vigorously and observed closely.

Acidosis↗
PubMed1993

Acidosis and metabolic rate in golden mantled ground squirrels (Spermophilus lateralis).

In this study, three series of experiments were conducted on euthermic, anesthetized, artificially ventilated golden mantled ground squirrels (Spermophilus lateralis), each of which altered pHa in a different fashion. In Series I, animals were randomly hypo- or hyper-ventilated. On average, pHa changed from 7.13 to 7.59, PaCO2 from 59.2 to 23.6 Torr, and PaO2 from 45.8 to 57.2 Torr between the two conditions, respectively. VO2 showed a significant positive correlation with pHa (r = +0.84) as well as PaO2 (r = + 0.60). In Series II, respiratory acidosis was produced by pump-ventilating animals with up to 10% inspired CO2 to reduce pHa to within the range 7.40 to 7.20. On average, pHa was reduced to 7.30, PaO2 to 50.1 Torr and PaCO2 was increased to 56.7 Torr. As in Series I, there was a significant positive correlation between VO2 and pHa (r = +0.78) and between VO2 and PaO2 (r = +0.71). In Series III, metabolic acidosis was produced by infusing lactic or acetic acid intravenously for 20 to 30 min. This reduced pHa from 7.56 to 7.32, PaO2 from 70.2 to 58.9 Torr, and elevated PaCO2 from 26.9 to 37.9 Torr (P < 0.05 in all cases). Contrary to Series I and II, VO2 increased with a decline in pHa (r = -0.65, P < 0.05) and PaO2 (r = -0.55, P < 0.05). Thus, despite a significant decline in pHa and PaO2 and an elevation of PaCO2 during all three series, VO2 changed in opposite directions during respiratory and metabolic acidosis. We conclude that whatever the mechanism involved, hypoventilation during the early stages of entrance into hibernation can contribute to the fall in metabolic rate.

Acidosis↗
PubMed2026

TTC19 and FMNL2 gene variants in a pediatric case of mitochondrial disorder with renal tubular acidosis.

Mitochondrial complex III deficiency caused by pathogenic variants in TTC19 is a heterogeneous disorder typically presenting with progressive neurological involvement in late childhood. Early-onset of disease with predominant renal manifestations are uncommon and may complicate diagnosis. We report a child presenting with developmental delay, failure to thrive, lactic acidosis, and distal renal tubular acidosis (dRTA), raising suspicion of an underlying mitochondrial disorder. Whole exome sequencing (WES) analysis identified a homozygous intron-exon boundary deletion of 31&#xa0;bp (c.463-19_474del) in TTC19 predicted to disrupt splicing, with functional evidence demonstrating aberrant transcript formation, reduced gene expression, and mitochondrial dysfunction in patient-derived fibroblasts. Based on the biochemical findings, re-analysis of exome data revealed a novel homozygous canonical splice-site variant (c.783-1G>A) in FMNL2. The splicing assay showed the skipping of exon 9, and reduced expression in the fibroblasts. This case expands the clinical spectrum of TTC19-related mitochondrial complex III deficiency with early-onset renal tubular acidosis. While TTC19 is the most plausible primary disease-causing gene, the functional disruption of FMNL2 suggests a potential contributory role or association with the renal phenotype. Hence, these findings highlight the importance of genomic re-analysis along with functional studies in resolving complex multisystem disorders.

Female↗
PubMed2001

Hypokalemic metabolic acidosis attributed to cough mixture abuse.

This report describes a patient with mixed normal anion gap hyperchloremic metabolic and respiratory acidosis associated with hypokalemia attributed to cough mixture abuse. Metabolic acidosis was likely related to an overdose of ammonium chloride, whereas respiratory acidosis was probably related to the effect of hypokalemia on respiratory muscles, causing hypoventilation. Hypokalemia was caused by a transcellular shift of potassium induced by ephedrine and pseudoephedrine. Both ammonium chloride and ephedrine were probably present in the cough mixture obtained by our patient as an over-the-counter medication. Physicians should be aware of the potential for cough mixture abuse to cause major electrolyte disturbances that may carry the risk for major cardiac arrhythmias, particularly in youth.

Acidosis↗
PubMed1997

Effect of extreme metabolic acidosis on oxygen delivery capacity of the blood--an in vitro investigation of changes in the oxyhemoglobin dissociation curve in blood with pH values of approximately 6.30.

OBJECTIVES: To determine the oxyhemoglobin dissociation curve in blood with pH of approximately 6.3 due to metabolic and superimposed respiratory acidosis, and to evaluate the oxygen delivery capacity of the blood under these circumstances. DESIGN: In vitro study. SETTING: A blood gas laboratory in a university institute for respiratory physiology. SUBJECTS: Heparinized normal human blood. INTERVENTIONS: The oxyhemoglobin dissociation curve was determined by measuring PO2, pH, PCO2, and hemoglobin oxygen saturation at 37 degrees C in mixtures of blood from two reservoirs, both prepared by titration with lactic acid to a pH of 6.3 during tonometry with gases containing 4.2% CO2 and high and low oxygen percentages, respectively. For determination of the effect of additional increases in PCO2, the reservoir blood thus produced was prepared by further tonometry with gases containing 12.8% CO2 and the same oxygen percentages. MEASUREMENTS AND MAIN RESULTS: With the same degree of lactic acidosis (blood lactate concentration of 52 mmol/L), the position of the oxyhemoglobin dissociation curve was the same for blood with PCO2 of 30 torr (4 kPa) and pH of 6.295 and for blood with PCO2 of 90 torr (12 kPa) and pH of 6.165. During tonometry with a gas with PCO2 of 30 torr (4 kPa) and PO2 of 20 torr (2.7 kPa) and addition of increasing amounts of lactic acid, leading to a stepwise change in pH from 6.7 to 6.0, hemoglobin oxygen saturation decreased with decreasing pH from 6.7 to 6.4, but remained the same at a pH of between 6.4 and 6.0. The measured rightward shift of the oxyhemoglobin dissociation curve at such a low pH was clearly less pronounced than that calculated using commonly applied equations, in particular, at the lowest pH. The beneficial effects of the rightward shift of the oxyhemoglobin dissociation curve on the estimates of extractable oxygen at a given venous PO2 decrease with decreasing pH, and disappear rapidly when the Pao2 is reduced below normal. CONCLUSIONS: The acidemia-induced rightward shift of the oxyhemoglobin dissociation curve does not increase further at a pH < 6.4, and is, at such extreme acidemia, less pronounced than calculated by the commonly used equations. To obtain optimal tissue oxygenation in patients with severe circulatory failure and extreme metabolic acidosis, Pao2 should be > 250 torr (> 33.3 kPa).

Acidosis, Lactic↗
PubMed1990

Triggering of erythropoietin production by hypoxia is inhibited by respiratory and metabolic acidosis.

Erythropoietin (EPO) production in response to hypoxic hypoxia is known to be attenuated by simultaneous hypercapnia. This study aimed to investigate whether this inhibitory effect of hypercapnia is 1) a direct effect of carbon dioxide or mediated by changes in pH or bicarbonate, 2) affects also carbon monoxide hypoxia, and 3) influences either the synthesis and release of EPO or the mechanisms by which hypoxia triggers an increase in EPO production rate. We found that EPO formation in mice exposed to normobaric hypoxia (8% O2) or to carbon monoxide (0.1%) was reduced by 30 and 42% when animals were simultaneously exposed to hypercapnia (7% CO2), by 35 and 38% when subjected to metabolic acidosis (NH4Cl), and unchanged when subjected to metabolic alkalosis (NaHCO3). In animals exposed to brief hypoxia (15 min) and subsequent normoxia (2 h), metabolic acidosis did not affect EPO levels when initiated after the hypoxic period. The results indicate that acidosis inhibits hypoxia-induced triggering of EPO formation independently of PCO2 and HCO3 levels. Because this inhibitory effect is also present during carbon monoxide hypoxia, it appears not solely due to potentiated hyperpnea. Alternatively, it may result from a facilitated intrarenal oxygen release or a direct effect at the EPO production sites.

Acid-Base Equilibrium↗
PubMed1991

Alteration in surface ion composition of cultured bone during metabolic, but not respiratory, acidosis.

Acidosis produced by a fall in [HCO3-] (metabolic acidosis, Met) produces greater Ca efflux from cultured bone than that produced by a rise in PCO2 (respiratory acidosis, Resp). To compare the effects of Met and Resp on bone surface ion composition we measured the surface abundance of 40Ca, 23Na, and 39K in cultured bone with a scanning ion microprobe utilizing secondary-ion mass spectrometry. Neonatal mouse calvariae were incubated for 24 h in medium simulating either Met (pH = 7.193 +/- 0.034, [HCO3-] = 15.1 +/- 1.4 meq/l), Resp (pH = 7.153 +/- 0.014, PCO2 = 85.4 +/- 1.2 mmHg) or normal physiological (Ctl; pH = 7.484 +/- 0.009, [HCO3-] = 29.7 +/- 0.7, PCO2 = 39.6 +/- 0.3) conditions. The surface of Ctl at 2-nm depth is rich in Na and K relative to Ca (Na/Ca = 25.6, K/Ca = 12.0, ratios of counts/s of secondary ions). Compared with Ctl, Met produced a sharp fall in both Na/Ca (6.5, P less than 0.01) and K/Ca (4.6, P less than 0.01), whereas Resp did not alter Na/Ca (23.8) or K/Ca (15.0). Ca efflux was greater in Met (873 +/- 54 nmol.bone-1.24 h-1) than in Resp (546 +/- 71 nmol.bone-1.24 h-1, P less than 0.01), which was greater than that in Ctl (315 +/- 49 nmol.bone-1.24 h-1, P less than 0.01 vs. Met and vs. Resp).(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed1968

An experimental renal acidification defect in patients with hereditary fructose intolerance. I. Its resemblance to renal tubular acidosis.

In three unrelated patients with hereditary fructose intolerance (HFI), but in none of five normal subjects, the experimental administration of fructose invariably induced a reversible dysfunction of the renal tubule with biochemical and physiological characteristics of renal tubular acidosis. During a state of ammonium chloride-induced acidosis, (a) urinary pH was greater than six and the rate of excretion of net acid (titratable acid plus ammonium minus bicarbonate) was inappropriately low, (b) the glomerular filtration rate remained unchanged or decreased modestly, and (c) urinary excretion of titratable acid increased briskly with diuresis of infused phosphate, although urinary pH changed little. The tubular dysfunction, which also includes impaired tubular reabsorption of alpha amino nitrogen and phosphate, persisted throughout administration of fructose and disappeared afterward. The tubular dysfunction was not causally dependent on hypoglucosemia, ammonium chloride-induced acidosis or osmotic diuresis. Rather, it appeared causally related to the fructose-induced metabolic abnormality of patients with HFI. The causal enzymatic defect, the virtual absence of fructose-1-phosphate aldolase, occurs in the kidney as well as in the liver of patients with HFI.

Acidosis↗
PubMed1993

Na+/H+ exchange in human lymphocytes and platelets in chronic and subacute metabolic acidosis.

The effect of acid-base disturbances on sodium/proton (Na+/H+) exchange has been examined in animal models; however, few data are available from human studies. To test the effect of metabolic acidosis on Na+/H+ exchange in man, as well as to examine the relationship between Na+/H+ exchange and cytosolic calcium ([Ca2+]i), we measured both variables in patients with decreased renal function with mild metabolic acidosis (pH 7.34 +/- 0.06), in normal control subjects (pH 7.41 +/- 0.02), and in subjects before (pH 7.40 +/- 0.01), and after (pH 7.26 +/- 0.04) ammonium chloride (NH4Cl) 15 g for 5 d. Lymphocytes and platelets were loaded with the cytosolic pH (pHi) indicator 2'-7'-bis(carboxyethyl)-5,6-carboxyfluorescein and acidified to pH approximately 6.6 with propionic acid. To quantitate Na+/H+ exchange, dpHi/dt was determined at 1 min. [Ca2+]i was measured with fura-2. Na+/H+ exchange was significantly increased only in lymphocytes of patients with renal insufficiency. Neither intracellular pH (pHi) nor [Ca2+]i was different from controls. NH4Cl resulted in a significant increase in Na+/H+ exchange in lymphocytes, but not in platelets of normal subjects. Values of pHi and [Ca2+]i in either cell type remained unaffected. Since metabolic acidosis influenced Na+/H+ only in lymphocytes, but not in platelets, it is possible that protein synthesis may be involved in increasing Na+/H+ exchange.

Acidosis↗
PubMed1979

Pyruvate carboxylase deficiency and lactic acidosis in a retarded child without Leigh's disease.

A child with lactic acidosis, severe mental and developmental retardation, and proximal renal tubular acidosis is presented. Biopsy and autopsy studies show severe hepatic, renal cortical, and cerebral deficiencies in pyruvate carboxylase (EC 6.4.1.1) activity. The patient had 1.81 +/- 0.20 units/g fresh weight at biopsy and 0.75 +/- 0.07 units/g fresh weight hepatic pyruvate carboxylase activity at autopsy compared with 10.9, 11.3, and 9.5 units/g fresh weight in two autopsy and one biopsy controls, respectively. The patient's renal cortical pyruvate carboxylase activity at autopsy was 0.008 +/- 0.004 units/g fresh weight compared with 5.05 units/g in the autopsy control. The patient had no detectable (less than 0.018 units/g fresh weight) cerebral pyruvate carboxylase activity at autopsy compared with 0.44, 0.53, and 0.695 units/g in the autopsy cerebrum of one human and two rhesus monkeys, respectively. Pyruvate dehydrogenase complex, phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.32), and fructose-1,6-bisphosphatase (EC 3.1.3.11) activities were in the normal range. The patient's urine pH was above 7.9 when the total serum CO2 was greater than 7.8 mM. However, the patient was able to acidify the urine to pH 5.1 when the total serum CO2 was 1.6 mM. The neuropathologic examination of the brain at autopsy revealed no sign of Leigh's disease, although developmental and degenerative lesions were observed. This is the first reported patient with a primary deficiency in hepatic, renal, and cerebral pyruvate carboxylase deficiency in whom the neuropathologic lesions, distinct from those of Leigh's disease, and proximal renal tubular acidosis have both been documented.

Acidosis↗
PubMed2002

Direct effect of acute metabolic and respiratory acidosis on parathyroid hormone secretion in the dog.

Because both metabolic (Met Acid) and respiratory acidosis (Resp Acid) have diverse effects on mineral metabolism, it has been difficult to establish whether acidosis directly affects parathyroid hormone (PTH) secretion. Our goal was to determine whether acute Met Acid and Resp Acid directly affected PTH secretion. Three groups of dogs were studied: control, acute Met Acid induced by HCl infusion, and acute Resp Acid induced by hypoventilation. EDTA was infused to prevent acidosis-induced increases in ionized calcium, but more EDTA was needed in Met Acid than in Resp Acid. The PTH response to EDTA-induced hypocalcemia was evaluated also. Magnesium needed to be infused in groups receiving EDTA to prevent hypomagnesemia. The half-life of intact PTH (iPTH) was determined during hypocalcemia when PTH was measured after parathyroidectomy. During normocalcemia, PTH values were greater (p < 0.05) in Met Acid (92 +/- 19 pg/ml) and Resp Acid (77 +/- 22 pg/ml) than in controls (27 +/- 5 pg/ml); the respective pH values were 7.23 +/- 0.01, 7.24 +/- 0.01, and 7.39 +/- 0.02. The maximal PTH response to hypocalcemia was greater (p < 0.05) in Met Acid (443 +/- 54 pg/ml) than in Resp Acid (267 +/- 37 pg/ml) and controls (262 +/- 48 pg/ml). The half-life of PTH was greater (p < 0.05) in Met Acid than in controls, but the PTH secretion rate also was greater (p < 0.05) in Met Acid than in the other two groups. In conclusion, (1) both acute Met Acid and Resp Acid increase PTH secretion when the ionized calcium concentration is normal; (2) acute Met Acid may increase the bone efflux of calcium more than Resp Acid; (3) acute Met Acid acts as a secretogogue for PTH secretion because it enhances the maximal PTH response to hypocalcemia.

Acidosis↗
PubMed1988

Toluene abuse and renal tubular acidosis in pregnancy.

Five gravidas presented with severe renal tubular acidosis from paint sniffing. Normal acid-base balance returned within 72 hours with cessation of toluene abuse and standard supportive measures. Fetal heart tracings and dynamic ultrasound parameters were normal in four of five cases. Three of five infants were growth-retarded at birth; two showed anomalies and neonatal hyperchloremic acidosis. These and previous cases of renal tubular acidosis in pregnancy suggest that toluene is teratogenic.

Acidosis↗
PubMed1982

Renal tubular acidosis with simultaneous lactic and keto acidoses: unusual manifestations of acute myelomonoblastic leukemia.

A 16-year-old male with severe metabolic acidosis required huge doses of sodium bicarbonate to alleviate his symptoms. Subsequent investigation showed that his bone marrow and kidneys were infiltrated with myelomonoblasts. His clinical course showed a temporal relationship between acute myelomonoblastic leukemia and metabolic acidosis. The literature on various etiologies of metabolic acidosis is reviewed. This is probably the first documented case of acute leukemia with the simultaneous occurrence of renal tubular, lactic and ketoacidoses.

Acidosis↗
PubMedDate not supplied

[Lactic acidosis and severe hyperkalemia in a diabetic patient treated with metformin and enalapril: influence of acute renal disease and drugs].

A 71 year old hypertensive and non insulin-dependent diabetic patients with moderate renal insufficiency taking 500 mg/d of metformin and 5 mg/d of enalapril, developed metabolic acidosis characterized by fairly elevated anion gap, hyperchloremia, severe hyperkalemia, normal plasma level of beta-hydroxybutyric acid, absence of ketonuria and high plasma level of lactic acid. This biochemical feature allowed us to ascribe the pathogenesis of metabolic acidosis both to the increased plasma level of lactic acid and to the type IV renal tubular acidosis syndrome, the precipitating factor being an infection of urinary tract (as we assumed on the basis of the urine culture). The patient was dehydrated and lethargic; the ECG revealed the presence of nonparoxysmal junctional tachycardia. The clinical evolution was favorable thanks to the treatment with the infusion of isotonic saline solutions, mild alkalinizing solutions, low-dose regular insulin and antibiotics. It is likely that metformin and enalapril, regularly assumed by the patient, could have played a iatrogenic role even if they were taken in low dosages. This event points out the importance of complying with the indications and especially the contraindications of these drugs, to avoid life threatening complications as that one occurred in this case.

Acidosis, Lactic↗