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Renal Tubular Acidosis Diagnosis Criteria

Metabolic Acidosis Treatment & Management

Metabolic Acidosis Treatment & Management

Approach Considerations Treatment of acute metabolic acidosis by alkali therapy is usually indicated to raise and maintain the plasma pH to greater than 7.20. In the following two circumstances this is particularly important. When the serum pH is below 7.20, a continued fall in the serum HCO3- level may result in a significant drop in pH. This is especially true when the PCO2 is close to the lower limit of compensation, which in an otherwise healthy young individual is approximately 15 mm Hg. With increasing age and other complicating illnesses, the limit of compensation is likely to be less. A further small drop in HCO3- at this point thus is not matched by a corresponding fall in PaCO2, and rapid decompensation can occur. For example, in a patient with metabolic acidosis with a serum HCO3- level of 9 mEq/L and a maximally compensated PCO2 of 20 mm Hg, a drop in the serum HCO3- level to 7 mEq/L results in a change in pH from 7.28 to 7.16. A second situation in which HCO3- correction should be considered is in well-compensated metabolic acidosis with impending respiratory failure. As metabolic acidosis continues in some patients, the increased ventilatory drive to lower the PaCO2 may not be sustainable because of respiratory muscle fatigue. In this situation, a PaCO2 that starts to rise may change the plasma pH dramatically even without a significant further fall in HCO3-. For example, in a patient with metabolic acidosis with a serum HCO3- level of 15 and a compensated PaCO2 of 27 mm Hg, a rise in PaCO2 to 37 mm Hg results in a change in pH from 7.33 to 7.20. A further rise of the PaCO2 to 43 mm Hg drops the pH to 7.14. All of this would have occurred while the serum HCO3- level remained at 15 mEq/L. In lactic acidosis and diabetic ketoacidosis, the organic anion can r Continue reading >>

Symptomatic Renal Tubular Acidosis (rta) In Patients With Systemic Lupus Erythematosus: An Analysis Of Six Cases With New Association Of Type 4 Rta

Symptomatic Renal Tubular Acidosis (rta) In Patients With Systemic Lupus Erythematosus: An Analysis Of Six Cases With New Association Of Type 4 Rta

Symptomatic renal tubular acidosis (RTA) in patients with systemic lupus erythematosus: an analysis of six cases with new association of type 4 RTA Correspondence to: L. B. Liou, Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital, Kwei-San Hsiang, Tao-Yuan County, Taiwan 333. E-mail: [email protected] Search for other works by this author on: Rheumatology, Volume 44, Issue 9, 1 September 2005, Pages 11761180, S. L. Li, L. B. Liou, J. T. Fang, W. P. Tsai; Symptomatic renal tubular acidosis (RTA) in patients with systemic lupus erythematosus: an analysis of six cases with new association of type 4 RTA, Rheumatology, Volume 44, Issue 9, 1 September 2005, Pages 11761180, Objectives. We have analysed the association between different parameters of renal tubular acidosis (RTA) with clinical and laboratory parameters in patients with systemic lupus erythematosus (SLE). Methods. Review of hospital database records between 1978 and 2003 revealed six SLE patients with RTA. Correlations and comparisons were done by Spearman rank correlation coefficient and the 2 test. Results. Four patients had hypokalaemia (type 1 RTA) and two patients had hyperkalaemia (type 4 RTA). Three patients with type 1, but no patients with type 4 RTA, had medullary nephrocalcinosis. The majority of SLE patients with distal RTA (type 1 and type 4) had nephritis with proteinuria. No seronegative SLE was noted, and all patients were negative for anticardiolipin antibodies. There was a noticeable trend of higher serum potassium levels with increased SLE Disease Activity Index (SLEDAI; P<0.1) and nephritic manifestation (haematuria, P<0.1). The mean SLEDAI scores were 11.75 and 27.5 for type 1 and type 4 RTA patients, respectively. Conclusions. When present in patients with Continue reading >>

Payperview: Renal Tubular Acidosis In Sjgren's Syndrome: A Case Series - Karger Publishers

Payperview: Renal Tubular Acidosis In Sjgren's Syndrome: A Case Series - Karger Publishers

I have read the Karger Terms and Conditions and agree. Background: The exact frequency of distal and proximal renal tubular acidosis (RTA) in Sjgren's syndrome is unknown. Other features of Sjgren's syndrome like polyuria, glomerular manifestations, familial occurrence and pregnancy are not widely reported. The aim was to prospectively study the clinical features and outcome of distal and proximal RTA in Sjgren's syndrome and also report on other renal manifestations of Sjgren's syndrome. Methods: The present study is a prospective consecutive case series of patients who presented with a history suggestive of RTA and Sjgren's syndrome. All patients were followed for 1 year. The diagnosis of RTA was by fractional excretion of bicarbonate. The diagnosis of Sjgren's syndrome was according to the American-European classification system [modified by Tzioufas and Voulgarelis: Best Pract Res Clin Rheumatol 2007;21:989-1010]. Results: The total number of RTA patients diagnosed during this period was 149. Sjgren's syndrome accounted for 34.8% (52 of 149) of RTA patients. The important symptoms and laboratory parameters were oral and ocular symptoms in 23 (44.2%), dental caries in 12 (23%), body pains in 47 (90.3%), mean serum pH 7.202 0.03, mean serum bicarbonate, 14.03 1.66 mmol/l, and mean urine pH, 7.125 0.54. There were 30 (57.6%) patients with distal RTA and 22 (42.3%) patients with proximal RTA. Conclusions: The clinical implication of the present study is that RTA is a common feature of Sjgren's syndrome. It may be missed if the presentation is not due to oral and ocular symptoms. The present study is also the only one with a 1-year follow-up. Sjgren H: Zur Kenntnis der Keratoconjunctivitis sicca (Keratitis filiformis bei Hypofunktion der Trnendrsen). Acta Ophthalmol 193 Continue reading >>

Renal Tubular Acidosis

Renal Tubular Acidosis

Patients with renal tubular acidosis (RTA) are often asymptomatic but may present with complaints of muscular weakness related to associated hypokalemia. Patients with severe acidemia can show hyperventilation or Kussmaul breathing due to respiratory compensation. Patients with RTA have a low arterial pH and serum bicarbonate with hyperchloremia and a normal serum anion gap. The urine pH exceeds 5.5 in classic distal RTA, but is lower than 5.0 in patients with untreated proximal RTA and is low also in hyperkalemic distal RTA. Alkali therapy is the mainstay of treatment. Potassium supplementation may be required for hypokalemia, and low-potassium diets are used if hyperkalemia is present. If hyperkalemic distal RTA is due to mineralocorticoid deficiency, fludrocortisone can be given unless it is contraindicated due to the presence of fluid overload or uncontrolled hypertension. Proximal RTA occurs most often as a component of Fanconi syndrome, which is characterized by generalized dysfunction of the proximal tubule, with the resultant urinary loss of bicarbonate, calcium, phosphate, urate, amino acids, glucose, and other organic acids and bases. In children, Fanconi syndrome causes growth retardation, renal rickets, and severe metabolic acidosis. Adult cases exhibit similar urinary losses, but the clinical impact is largely restricted to metabolic acidosis. Fanconi syndrome is marked by the appearance in the urine of all amino acids. Specific amino aciduria as seen in isolated cystinuria, glucose loss in isolated glycosuria, and isolated phosphaturia do not constitute Fanconi syndrome. The term renal tubular acidosis (RTA) describes any one of a number of disorders, in which the excretion of fixed acid (distal RTA) or the reabsorption of filtered bicarbonate (proximal R Continue reading >>

Approach To The Patient With Renal Tubular Acidosis - Oxford Medicine

Approach To The Patient With Renal Tubular Acidosis - Oxford Medicine

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com).Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice ). The renal tubular acidoses are a collection of syndromes characterized by defective urinary acidification. These syndromes have classically caused some confusion, and many opine that the widely used numerical system (type 1, 2) should be abandoned. We consider distal renal tubular acidosis and proximal renal tubular acidosis separately, and briefly cover hypoaldosteronism.Distal (Type 1) renal tubular acidosis is a syndrome of hypokalaemia, metabolic acidosis, kidney stones, nephrocalcinosis, and osteomalacia or rickets. It is caused by failure of the acid secreting -intercalated cells in the distal nephron.Proximal (Type 2) renal tubular acidosis is a syndrome of metabolic acidosis that is almost always accompanied by the Fanconi syndrome of glycosuria, phosphaturia, uricosuria, aminoaciduria, and low-molecular-weight proteinuria. It is caused by a failure of bicarbonate reabsorption by the proximal tubular cells.Type 3 or mixed renal tubular acidosis, as originally described, has vanished (or was originally incompletely described). It is sometimes used to describe a mutation of carbonic anhydrase II, which causes both proximal and distal renal tubular acidosis, as well as cerebral calcification and osteopetrosis.Type 4 or hypoaldosteronism is a syndrome of hyperkalaemia and mild metabolic acidosis. It is due to a lack of aldosterone or resistance to its action. Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Continue reading >>

Renal Tubular Acidosis And Uraemic Acidosis

Renal Tubular Acidosis And Uraemic Acidosis

Metabolic acidosis can occur in both acute and chronic renal disorders the anion gap may be elevated, due to uraemic acidosis the anion gap may be normal, due to renal tubular acidosis (RTA) Uraemic acidosis results from the loss of functional nephrons decreased glomerular filtration rate (GFR) (e.g. <20 mL/min) accumulation of acidic anions such as phosphate and sulfate occurs causes high anion gap metabolic acidosis (HAGMA) patients manifest as renal failure, often have prolonged survival and develop chronic complications such as bone demineralisation Renal tubular acidosis (RTA) involves defects isolated to the renal tubules only GFR may be normal or only minimally affected primary problem is defective renal acid-base regulation due to impaired ability to acidify the urine and excrete acid results in net acid retention and hyperchloremic normal anion gap metabolic acidosis (NAGMA) may be incomplete and only develop in the presence of an acid load occurs despite a normal or only mildly reduced glomerular filtration rate (GFR) RTA is often detected incidentally through an abnormal blood workup, but some patients present with clinical features such as poor growth, dehydration, or altered mental state COMPARISON OF TYPES OF RENAL TUBULAR ACIDOSIS (RTA) urine pH remains >5.5 despite severe acidaemia (HCO3 < 15mmol/L) HCO3 loading test leads to increased urinary HCO3 may require an acid load test to see whether urinary pH remains > 5.5 hyperchloraemic acidosis, alkaline urine, and renal stone formation secondary hyperaldosteronism results in increased K+ loss in urine NaHCO3 (corrects Na+ deficit, ECF volume and corrects hypokalaemia) sodium and potassium citrate solutions can be useful if hypokalaemia persistent citrate also binds Ca2+ in the urine and can help to preven Continue reading >>

Primary Distal Renal Tubular Acidosis - Nord (national Organization For Rare Disorders)

Primary Distal Renal Tubular Acidosis - Nord (national Organization For Rare Disorders)

NORD gratefully acknowledges Daniel Batlle, MD, Earle, del Greco Levin Professor of Nephrology/ Hypertension, Professor of Medicine, Northwestern University Feinberg School of Medicine, Division of Nephrology/ Hypertension, for assistance in the preparation of this report. Synonyms of Primary Distal Renal Tubular Acidosis Subdivisions of Primary Distal Renal Tubular Acidosis ATP6V1B1-associated distal renal tubular acidosis ATP6V0A4-associated distal renal tubular acidosis SLC4A1-associated distal renal tubular acidosis Primary distal renal tubular acidosis (dRTA) is a rare genetic disorder that affects the ability of the kidneys to remove acid from the blood. This leads to metabolic acidosis. Metabolic acidosis is a condition in which the circulating chemical acids and bases are out of balance. The blood of affected individuals contains too much acid and the urine contains too little acid. Chronic metabolic acidosis can lead to a variety of symptoms. The specific signs, symptoms, and severity of this disorder can vary from one person to another. There are different forms of primary distal renal tubular acidosis. They are caused by a variation (mutation) in one of at least three different genes; the SLC4A1 gene, the ATP6V0A4 gene, and the ATP6V1B1 gene. A variation in the SLC4A1 gene is usually inherited in an autosomal dominant pattern, and less often in an autosomal recessive pattern. Variations in the ATP6V0A4 and ATP6V1B1 genes are usually inherited in an autosomal recessive pattern. A mixture of sodium and potassium salts in the form of sodium citrate or potassium citrate liquid solutions is usually recommended. Liquid preparations, however, have poor palatability and acceptance among patients. In this case, sodium bicarbonate tablets are used instead or in additi Continue reading >>

Distal Renal Tubular Acidosis

Distal Renal Tubular Acidosis

Distal renal tubular acidosis (dRTA) or Type 1 renal tubular acidosis (RTA) is the classical form of RTA, being the first described. Distal RTA is characterized by a failure of acid secretion by the alpha intercalated cells of the cortical collecting duct of the distal nephron . This failure of acid secretion may be due to a number of causes, and it leads to an inability to acidify the urine to a pH of less than 5.3. Radiograph of a rickets sufferer, a complication of both distal and proximal RTA. Because renal excretion is the primary means of eliminating acid from the body, there is consequently a tendency towards acidemia . This leads to the clinical features of dRTA: [1] Urinary stone formation (related to alkaline urine, hypercalciuria , and low urinary citrate). [2] Nephrocalcinosis (deposition of calcium in the substance of the kidney) Bone demineralisation (causing rickets in children and osteomalacia in adults) The symptoms and sequelae of dRTA are variable and range from being completely asymptomatic , to loin pain and hematuria from kidney stones , to failure to thrive and severe rickets in childhood forms as well as possible renal failure and even death. dRTA commonly leads to sodium loss and volume contraction, which causes a compensatory increase in blood levels of aldosterone . [3] Aldosterone causes increased resorption of sodium and loss of potassium in the collecting duct of the kidney, so these increased aldosterone levels cause the hypokalemia which is a common symptom of dRTA. [3] The pH of patient's blood is highly variable, and acidemia is not necessarily characteristic of sufferers of dRTA at any given time. One may have dRTA caused by alpha intercalated cell failure without necessarily being acidemic; termed incomplete dRTA, which is characteri Continue reading >>

Renal Tubular Acidosis

Renal Tubular Acidosis

Renal tubular acidosis (RTA) is acidosis and electrolyte disturbances due to impaired renal hydrogen ion excretion (type 1), impaired bicarbonate resorption (type 2), or abnormal aldosterone production or response (type 4). (Type 3 is extremely rare and is not discussed.) Patients may be asymptomatic, display symptoms and signs of electrolyte derangements, or progress to chronic kidney disease. Diagnosis is based on characteristic changes in urine pH and electrolytes in response to provocative testing. Treatment corrects pH and electrolyte imbalances using alkaline agents, electrolytes, and, rarely, drugs. RTA defines a class of disorders in which excretion of hydrogen ions or reabsorption of filtered bicarbonate is impaired, leading to a chronic metabolic acidosis with a normal anion gap. Hyperchloremia is usually present, and secondary derangements may involve other electrolytes, such as potassium (frequently) and calcium (rarelysee Table: Some Features of Different Types of Renal Tubular Acidosis* ). Chronic RTA is often associated with structural damage to renal tubules and may progress to chronic kidney disease . Some Features of Different Types of Renal Tubular Acidosis* Treatment of concomitant abnormalities related to potassium, calcium, and phosphate metabolism Treatment consists of correction of pH and electrolyte balance with alkali therapy. Failure to treat RTA in children slows growth. Alkaline agents such as sodium bicarbonate, potassium bicarbonate, or sodium citrate help achieve a relatively normal plasma bicarbonate concentration (22 to 24 mEq/L). Potassium citrate can be substituted when persistent hypokalemia is present or, because sodium increases calcium excretion, when calcium calculi are present. Vitamin D (eg, ergocalciferol 800 IU po once/day) Continue reading >>

Renal Tubular Acidosis With Hypokalemia Symptoms

Renal Tubular Acidosis With Hypokalemia Symptoms

Renal Tubular Acidosis with Hypokalemia Symptoms As understood today, renal tubular acidosis is a derangement characterized by an impairment of acidifying the urine despite systemic acidosis, even though glomerular function is intact.1 Well-established diagnostic criteria define the disorder as a clinical entity,1-5,19 but recognition, as a rule, is delayed until symptoms of the associated nephrolithiasis stimulate further investigation. Since nephrocalcinosis and nephrolithiasis are secondary manifestations of the disorder, the diagnosis, in most instances, is not made early in the course of the disease. In the case to be presented here the disorder has been encountered in an exceptionally early stage. Symptoms of hypokalemia alone dominated the clinical picture without any suggestive evidence of kidney stones or intrinsic renal disease. Following basic workup the diagnosis has been substantiated by a positive ammonium chloride loading test and has been amplified by x-ray studies and a percutaneous biopsy of the kidney. Continue reading >>

Incidence Of Renal Tubular Acidosis In Nephrology Unit In Assiut University Childern Hospital

Incidence Of Renal Tubular Acidosis In Nephrology Unit In Assiut University Childern Hospital

You have reached the maximum number of saved studies (100). Please remove one or more studies before adding more. Incidence of Renal Tubular Acidosis in Nephrology Unit in Assiut University Childern Hospital The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Verified August 2017 by Sally Ezzat Shafik mikhail, Assiut University. Recruitment status was: Not yet recruiting Information provided by (Responsible Party): Sally Ezzat Shafik mikhail, Assiut University Top of Page Study Description Study Design Groups and Cohorts Outcome Measures Eligibility Criteria Contacts and Locations More Information Providing summarized information on the clinical and biochemical characteristics and types of renal tubular acidosis in children in Assiut University Childern Hospital. Diagnostic Test: Arterial blood gases Diagnostic Test: Blood anion gap Diagnostic Test: serum electrolytes Diagnostic Test: renal function test Diagnostic Test: urine analysis The term renal tubular acidosis (RTA) is applied to a group of transport defects in the reabsorption of bicarbonate (HCO3_), the excretion of hydrogen ion (H_), or both. This condition was first described in 1935, confirmed as a renal tubular disorder in 1946, and designated "renal tubular acidosis" in 1951. The RTA syndromes are characterized by a relatively normal GFR and a metabolic acidosis accompanied by hyperchloremia and a normal plasma anion gap. RTA is classified into 4 major forms: distal, proximal, hyperkalemic and combined RTA. Distal RTA is associated with reduced urinary acid secretion, proximal RTA ( pRTA ) is characterized by impaired bicarbonate (H Continue reading >>

(pdf) Furosemide/fludrocortisone Test And Clinical Parameters To Diagnose Incomplete Distal Renal Tubular Acidosis In Kidney Stone Formers

(pdf) Furosemide/fludrocortisone Test And Clinical Parameters To Diagnose Incomplete Distal Renal Tubular Acidosis In Kidney Stone Formers

Background and objectives Incomplete distal renal tubular acidosis is a well known cause of calcareous nephrolithiasis but the prevalence is unknown, mostly due to lack of accepted diagnostic tests and criteria. The ammonium chloride test is considered as gold standard for the diagnosis of incomplete distal renal tubular acidosis, but the furosemide/udrocortisone test was recently proposed as an alternative. Because of the lack of rigorous comparative studies, the validity of the furosemide/udrocortisone test in stone formers remains unknown. In addition, the performance of conventional, nonprovocative parameters in predicting incomplete distal renal tubular acidosis has not been studied. Design, setting, participants, & measurements We conducted a prospective study in an unselected cohort of 170 stone formers that underwent sequential ammonium chloride and furosemide/udrocortisone testing. Results Using the ammonium chloride test as gold standard, the prevalence of incomplete distal renal tubular acidosis was 8%. Sensitivity and specicity of the furosemide/udrocortisone test were 77% and 85%, respectively, yielding a positive predictive value of 30% and a negative predictive value of 98%. Testing of several nonprovocative clinical parameters in the prediction of incomplete distal renal tubular acidosis revealed fasting morning urinary pH and plasma potassium as the most discriminative parameters. The combination of a fasting morning u rinary threshold pH ,5.3 with a pla sma potassium threshold .3. 8 mEq/L yielded a negative predictive value of 98% with a sensitivity of 85% and a specicity of 77% for the diagnosis of incomplete distal Conclusions The furosemide/udrocortisone test can be used for incomplete distal renal tubular acidosis screening in stone formers, but a Continue reading >>

Prevalence And Characterization Of Renal Tubular Acidosis In Patients With Osteopenia And Osteoporosis And In Nonporotic Controls

Prevalence And Characterization Of Renal Tubular Acidosis In Patients With Osteopenia And Osteoporosis And In Nonporotic Controls

Prevalence and characterization of renal tubular acidosis in patients with osteopenia and osteoporosis and in nonporotic controls Department of Internal Medicine, Krankenhaus der Barmherzigen Brder, Graz, Austria Search for other works by this author on: Department of Internal Medicine, Krankenhaus der Barmherzigen Brder, Graz, Austria Search for other works by this author on: Department of Internal Medicine, Krankenhaus der Barmherzigen Brder, Graz, Austria Search for other works by this author on: Department of Internal Medicine, Krankenhaus der Barmherzigen Brder, Graz, Austria Search for other works by this author on: Department of Internal Medicine, Krankenhaus der Barmherzigen Brder, Graz, Austria Search for other works by this author on: Nephrology Dialysis Transplantation, Volume 15, Issue 7, July 2000, Pages 975980, Wolfgang Weger, Peter Kotanko, Martin Weger, Hannes Deutschmann, Falko Skrabal, Prevalence and characterization of renal tubular acidosis in patients with osteopenia and osteoporosis and in nonporotic controls, Nephrology Dialysis Transplantation, Volume 15, Issue 7, July 2000, Pages 975980, Background. Chronic metabolic acidosis may increase alkali mobilization from the bone and thus promote the development of osteoporosis. The objective of the current study was to compare urinary acidification in patients with reduced bone mineral content with that in control subjects with normal bone density. Methods. Fortysix subjects (41 females, 5 males) with osteopenia or osteoporosis were studied. In none of the subjects were overt metabolic acidosis, derangement of potassium homeostasis, or renal insufficiency present. Distal tubular acidification was studied by means of oral ammonium chloride loading test (0.1 g/kg body weight) and the oral frusemide test Continue reading >>

Renal Tubular Acidosis Is Highly Prevalent In Critically Ill Patients

Renal Tubular Acidosis Is Highly Prevalent In Critically Ill Patients

Renal tubular acidosis is highly prevalent in critically ill patients Brunner et al.; licensee BioMed Central.2015 Hyperchloremic acidosis is frequent in critically ill patients. Renal tubular acidosis (RTA) may contribute to acidemia in the state of hyperchloremic acidosis, but the prevalence of RTA has never been studied in critically ill patients. Therefore, we aimed to investigate the prevalence, type, and possible risk factors of RTA in critically ill patients using a physical-chemical approach. This prospective, observational trial was conducted in a medical ICU of a university hospital. One hundred consecutive critically ill patients at the age 18, expected to stay in the ICU for 24h, with the clinical necessity for a urinary catheter and the absence of anuria were included. Base excess (BE) subset calculation based on a physical-chemical approach on the first 7days after ICU admission was used to compare the effects of free water, chloride, albumin, and unmeasured anions on the standard base excess. Calculation of the urine osmolal gap (UOG) - as an approximate measure of the unmeasured urine cation NH4 + - served as determinate between renal and extrarenal bicarbonate loss in the state of hyperchloremic acidosis. During the first week of ICU stay 43 of the patients presented with hyperchloremic acidosis on one or more days represented as pronounced negative BEChloride. In 31 patients hyperchloremic acidosis was associated with RTA characterized by a UOG 150mosmol/kg in combination with preserved renal function. However, in 26 of the 31 patients with RTA metabolic acidosis was neutralized by other acid-base disturbances leading to a normal arterial pH. RTA is highly prevalent in critically ill patients with hyperchloremic acidosis, whereas it is often neutraliz Continue reading >>

Renal Tubular Acidosis | The Online Metabolic And Molecular Bases Of Inherited Disease | Ommbid | Mcgraw-hill Medical

Renal Tubular Acidosis | The Online Metabolic And Molecular Bases Of Inherited Disease | Ommbid | Mcgraw-hill Medical

Renal tubular acidosis (RTA) is a clinical syndrome characterized by hyperchloremic metabolic acidosis secondary to an abnormality in renal acidification. The acidification defect may be manifested by an inappropriately high urine pH, bicarbonaturia, and, by definition, reduced net acid excretion. Classical distal renal tubular acidosis and proximal renal tubular acidosis are frequently associated with hypokalemia. Distal renal tubular acidosis can also result from a generalized dysfunction of the distal nephron, in which case it is usually accompanied by hyperkalemia and may be associated with either hypoaldosteronism or aldosterone resistance. Proximal renal tubular acidosis may result from an isolated defect of acidification in the proximal nephron. The isolated defect in acidification could be the result of selective dysfunction of the Na+/H+ antiporter, the proximal tubule H+-ATPase or the Na+/HCO3 /CO3 = symporter. More commonly, proximal renal tubular acidosis occurs as one manifestation of a generalized defect in proximal tubule function. Patients with this generalized abnormality, the Fanconi syndrome, usually have glycosuria, aminoaciduria, citraturia, and phosphaturia. The acidification defect associated with this generalized tubular dysfunction may be the result of (a) impairment of cellular ATP generation, (b) cellular phosphate depletion, or (c) a selective abnormality of the basolateral Na+, K+-ATPase. Vitamin D deficiency is associated with the Fanconi lesion. The transport defect may be due to a combination of factors including reduction in 1,25-dihydroxy vitamin D3 levels, elevated parathyroid hormone levels, hypocalcemia, and intracellular phosphate depletion. The diagnosis of proximal renal tubular acidosis is based on the demonstration of a chronic Continue reading >>

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