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Sterns RH, Rondon-Berrios H. Cerebral Salt Wasting Is a Real Cause of Hyponatremia: CON. KIDNEY360 2023; 4:e441-e444. [PMID: 37103960 PMCID: PMC10513112 DOI: 10.34067/kid.0001412022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Richard H. Sterns
- University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Helbert Rondon-Berrios
- Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Pazoki R, Evangelou E, Mosen-Ansorena D, Pinto RC, Karaman I, Blakeley P, Gill D, Zuber V, Elliott P, Tzoulaki I, Dehghan A. GWAS for urinary sodium and potassium excretion highlights pathways shared with cardiovascular traits. Nat Commun 2019; 10:3653. [PMID: 31409800 PMCID: PMC6692500 DOI: 10.1038/s41467-019-11451-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 06/27/2019] [Indexed: 01/04/2023] Open
Abstract
Urinary sodium and potassium excretion are associated with blood pressure (BP) and cardiovascular disease (CVD). The exact biological link between these traits is yet to be elucidated. Here, we identify 50 loci for sodium and 13 for potassium excretion in a large-scale genome-wide association study (GWAS) on urinary sodium and potassium excretion using data from 446,237 individuals of European descent from the UK Biobank study. We extensively interrogate the results using multiple analyses such as Mendelian randomization, functional assessment, co localization, genetic risk score, and pathway analyses. We identify a shared genetic component between urinary sodium and potassium expression and cardiovascular traits. Ingenuity pathway analysis shows that urinary sodium and potassium excretion loci are over-represented in behavioural response to stimuli. Our study highlights pathways that are shared between urinary sodium and potassium excretion and cardiovascular traits.
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Affiliation(s)
- Raha Pazoki
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
| | - Evangelos Evangelou
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- Department of Hygiene and Epidemiology, University of Ioannina Medical School, 45110, Ioannina, Greece
| | - David Mosen-Ansorena
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
| | - Rui Climaco Pinto
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- Dementia Research Institute at Imperial College London, London, W2 1PG, UK
| | - Ibrahim Karaman
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- Dementia Research Institute at Imperial College London, London, W2 1PG, UK
| | - Paul Blakeley
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- NIHR Imperial Biomedical Research Centre, ITMAT Data Science Group, Imperial College London, London, W2 1PG, UK
| | - Dipender Gill
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- Department of Stroke Medicine, Imperial College London, London, W2 1PG, UK
| | - Verena Zuber
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
| | - Paul Elliott
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK
- Dementia Research Institute at Imperial College London, London, W2 1PG, UK
- Imperial College NIHR Biomedical Research Centre, London, W2 1NY, UK
- Health Data Research UK-London, London, NW1 2BE, UK
| | - Ioanna Tzoulaki
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK.
- Department of Hygiene and Epidemiology, University of Ioannina Medical School, 45110, Ioannina, Greece.
- Dementia Research Institute at Imperial College London, London, W2 1PG, UK.
| | - Abbas Dehghan
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of Public Health, St Mary's campus, Norfolk Place, London, W2 1PG, UK.
- Dementia Research Institute at Imperial College London, London, W2 1PG, UK.
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Maesaka JK, Imbriano LJ, Miyawaki N. Determining Fractional Urate Excretion Rates in Hyponatremic Conditions and Improved Methods to Distinguish Cerebral/Renal Salt Wasting From the Syndrome of Inappropriate Secretion of Antidiuretic Hormone. Front Med (Lausanne) 2018; 5:319. [PMID: 30560127 PMCID: PMC6284366 DOI: 10.3389/fmed.2018.00319] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/29/2018] [Indexed: 01/02/2023] Open
Abstract
Our evaluation of hyponatremic patients is in a state of confusion because the assessment of the volume status of the patient and determinations of urine sodium concentrations (UNa) >30–40 mEq/L have dominated our approach despite documented evidence of many shortcomings. Central to this confusion is our inability to differentiate cerebral/renal salt wasting (C/RSW) from the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), syndromes with diametrically opposing therapeutic goals. The recent proposal to treat most or all hyponatremic patients makes differentiation even more important and reports of C/RSW occurring without cerebral disease leads to a clinically important proposal to change cerebral to renal salt wasting (RSW). Differentiating SIADH from RSW is difficult because of identical clinical parameters that characterize both syndromes. Determination of fractional urate excretion (FEurate) is central to a new algorithm, which has proven to be superior to current methods. We utilized this algorithm and differences in physiologic response to isotonic saline infusions between SIADH and RSW to evaluate hyponatremic patients from the general medical wards of the hospital. In 62 hyponatremic patients, 17 (27%) had SIADH, 19 (31%) had reset osmostat (RO), 24 (38%) had RSW, 1 due to HCTZ and 1 Addison's disease. Interestingly, 21 of 24 with RSW had no evidence of cerebral disease and 10 of 24 with RSW had UNa < 20 mEqL. We conclude that 1. RSW is much more common than is perceived, 2.the term cerebral salt wasting should be changed to RSW 3. RO should be eliminated as a subclass of SIADH, 4. SIADH should be redefined 5. The volume approach is ineffective and 6. There are limitations to determining UNa, plasma renin, aldosterone or atrial/brain natriuretic peptides. We also present data on a natriuretic peptide found in sera of patients with RSW and Alzheimer's disease.
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Affiliation(s)
- John K Maesaka
- Division of Nephrology and Hypertension, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, United States
| | - Louis J Imbriano
- Division of Nephrology and Hypertension, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, United States
| | - Nobuyuki Miyawaki
- Division of Nephrology and Hypertension, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, United States
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Maesaka JK, Imbriano LJ, Miyawaki N. Application of established pathophysiologic processes brings greater clarity to diagnosis and treatment of hyponatremia. World J Nephrol 2017; 6:59-71. [PMID: 28316939 PMCID: PMC5339638 DOI: 10.5527/wjn.v6.i2.59] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/18/2016] [Accepted: 12/28/2016] [Indexed: 02/06/2023] Open
Abstract
Hyponatremia, serum sodium < 135 mEq/L, is the most common electrolyte abnormality and is in a state of flux. Hyponatremic patients are symptomatic and should be treated but our inability to consistently determine the causes of hyponatremia has hampered the delivery of appropriate therapy. This is especially applicable to differentiating syndrome of inappropriate antidiuresis (SIAD) from cerebral salt wasting (CSW) or more appropriately, renal salt wasting (RSW), because of divergent therapeutic goals, to water-restrict in SIAD and administer salt and water in RSW. Differentiating SIAD from RSW is extremely difficult because of identical clinical parameters that define both syndromes and the mindset that CSW occurs rarely. It is thus insufficient to make the diagnosis of SIAD simply because it meets the defined characteristics. We review the pathophysiology of SIAD and RSW, the evolution of an algorithm that is based on determinations of fractional excretion of urate and distinctive responses to saline infusions to differentiate SIAD from RSW. This algorithm also simplifies the diagnosis of hyponatremic patients due to Addison’s disease, reset osmostat and prerenal states. It is a common perception that we cannot accurately assess the volume status of a patient by clinical criteria. Our algorithm eliminates the need to determine the volume status with the realization that too many factors affect plasma renin, aldosterone, atrial/brain natriuretic peptide or urine sodium concentration to be useful. Reports and increasing recognition of RSW occurring in patients without evidence of cerebral disease should thus elicit the need to consider RSW in a broader group of patients and to question any diagnosis of SIAD. Based on the accumulation of supporting data, we make the clinically important proposal to change CSW to RSW, to eliminate reset osmostat as type C SIAD and stress the need for a new definition of SIAD.
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Imbriano LJ, Mattana J, Drakakis J, Maesaka JK. Identifying Different Causes of Hyponatremia With Fractional Excretion of Uric Acid. Am J Med Sci 2016; 352:385-390. [PMID: 27776720 DOI: 10.1016/j.amjms.2016.05.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/04/2016] [Accepted: 05/13/2016] [Indexed: 01/17/2023]
Abstract
BACKGROUND There is controversy over the prevalence of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral or renal salt wasting (RSW), 2 syndromes with identical common clinical and laboratory parameters but different therapies. The traditional approach to the hyponatremic patient relies on volume assessment, but there are limitations to this method. METHODS We used an algorithm that relies on fractional excretion of urate (FEurate) to evaluate patients with hyponatremia and present 4 illustrative cases. RESULTS Overall, 2 patients had increased FEurate [normal: 4-11%], as is seen in SIADH and RSW. A diagnosis of SIADH was made in 1 patient by correcting the hyponatremia with 1.5% saline and observing a characteristic normalization of an elevated FEurate that is characteristic of SIADH as compared to FEurate being persistently increased in RSW. A patient with T-cell lymphoma had symmetrical leg edema due to lymphomatous obstruction of the inferior vena cava, postural hypotension, pleural effusion, ascites, decreased cardiac output and urine sodium level of 10mmol/L. Saline-induced excretion of dilute urines and undetectable plasma antidiuretic hormone were consistent with RSW. Furosemide, given for presumed heart failure, induced a profound diuresis that required large volumes of fluid resuscitation. A normal FEurate identified a reset osmostat in a transplant patient with a slowly developing pneumocystis carinii pneumonia. A volume-depleted hyponatremic patient with Addison׳s disease had a low FEurate of 1.4%. CONCLUSIONS These illustrative cases suggest that an approach to hyponatremia using FEurate may be a useful alternative to traditional volume-based approaches.
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Affiliation(s)
- Louis J Imbriano
- Department of Medicine, Winthrop-University Hospital, Mineola, New York
| | - Joseph Mattana
- Department of Medicine, Winthrop-University Hospital, Mineola, New York
| | - James Drakakis
- Department of Medicine, Winthrop-University Hospital, Mineola, New York
| | - John K Maesaka
- Department of Medicine, Winthrop-University Hospital, Mineola, New York.
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Stimulation of V1a receptor increases renal uric acid clearance via urate transporters: insight into pathogenesis of hypouricemia in SIADH. Clin Exp Nephrol 2016; 20:845-852. [PMID: 26935049 DOI: 10.1007/s10157-016-1248-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/11/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND Hypouricemia is pathognomonic in syndrome of inappropriate secretion of antidiuretic hormone (SIADH) but the underlying mechanism remains unclear. Based on the previous studies, we hypothesized that V1a receptor may play a principal role in inducing hypouricemia in SIADH and examined uric acid metabolism using a rat model. METHODS Terlipressin (25 ng/h), a selective V1a agonist, was subcutaneously infused to 7-week-old male Wistar rats (n = 9). Control rats were infused with normal saline (n = 9). The rats were sacrificed to obtain kidney tissues 3 days after treatment. In addition to electrolyte metabolism, changes in expressions of the urate transporters including URAT1 (SLC22A12), GLUT9 (SLC2A9), ABCG2 and NPT1 (SLC17A1) were examined by western blotting and immunohistochemistry. RESULTS In the terlipressin-treated rats, serum uric acid (UA) significantly decreased and the excretion of urinary UA significantly increased, resulting in marked increase in fractional excretion of UA. Although no change in the expression of URAT1, GLUT9 expression significantly decreased whereas the expressions of ABCG2 and NPT1 significantly increased in the terlipressin group. The results of immunohistochemistry corroborated with those of the western blotting. Aquaporin 2 expression did not change in the medulla, suggesting the independence of V2 receptor stimulation. CONCLUSION Stimulation of V1a receptor induces the downregulation of GLUT9, reabsorption urate transporter, together with the upregulation of ABCG2 and NPT1, secretion urate transporters, all changes of which clearly lead to increase in renal UA clearance. Hypouricemia seen in SIADH is attributable to V1a receptor stimulation.
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Maesaka JK, Imbriano L, Mattana J, Gallagher D, Bade N, Sharif S. Differentiating SIADH from Cerebral/Renal Salt Wasting: Failure of the Volume Approach and Need for a New Approach to Hyponatremia. J Clin Med 2014; 3:1373-85. [PMID: 26237607 PMCID: PMC4470189 DOI: 10.3390/jcm3041373] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 08/26/2014] [Accepted: 09/09/2014] [Indexed: 12/27/2022] Open
Abstract
Hyponatremia is the most common electrolyte abnormality. Its diagnostic and therapeutic approaches are in a state of flux. It is evident that hyponatremic patients are symptomatic with a potential for serious consequences at sodium levels that were once considered trivial. The recommendation to treat virtually all hyponatremics exposes the need to resolve the diagnostic and therapeutic dilemma of deciding whether to water restrict a patient with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or administer salt and water to a renal salt waster. In this review, we briefly discuss the pathophysiology of SIADH and renal salt wasting (RSW), and the difficulty in differentiating SIADH from RSW, and review the origin of the perceived rarity of RSW, as well as the value of determining fractional excretion of urate (FEurate) in differentiating both syndromes, the high prevalence of RSW which highlights the inadequacy of the volume approach to hyponatremia, the importance of changing cerebral salt wasting to RSW, and the proposal to eliminate reset osmostat as a subtype of SIADH, and finally propose a new algorithm to replace the outmoded volume approach by highlighting FEurate. This algorithm eliminates the need to assess the volume status with less reliance on determining urine sodium concentration, plasma renin, aldosterone and atrial/brain natriuretic peptide or the BUN to creatinine ratio.
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Affiliation(s)
- John K Maesaka
- Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA.
| | - Louis Imbriano
- Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA.
| | - Joseph Mattana
- Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA.
| | - Dympna Gallagher
- Department of Medicine, Columbia University, New York, NY 10027, USA.
| | - Naveen Bade
- Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA.
| | - Sairah Sharif
- Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA.
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Bitew S, Imbriano L, Miyawaki N, Fishbane S, Maesaka JK. More on renal salt wasting without cerebral disease: response to saline infusion. Clin J Am Soc Nephrol 2009; 4:309-15. [PMID: 19201917 PMCID: PMC2637602 DOI: 10.2215/cjn.02740608] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 11/17/2008] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES The existence and prevalence of cerebral salt wasting (CSW) or the preferred term, renal salt wasting (RSW), and its differentiation from syndrome of inappropriate antidiuretic hormone (SIADH) have been controversial. This controversy stems from overlapping clinical and laboratory findings and an inability to assess the volume status of these patients. The authors report another case of RSW without clinical cerebral disease and contrast it to SIADH. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Three patients with hyponatremia, hypouricemia, increased fractional excretion (FE) of urate, urine sodium >20 mmol/L, and concentrated urines were infused with isotonic saline after collection of baseline data. RESULTS One patient with RSW had pneumonia without cerebral disease and showed increased plasma aldosterone and FEphosphate, and two patients with SIADH had increased blood volume, low plasma renin and aldosterone, and normal FEphosphate. The patient with RSW responded to isotonic saline by excretion of dilute urines, prompt correction of hyponatremia, and normal water loading test after volume repletion. Hypouricemia and increased FEurate persisted after correction of hyponatremia. Two patients with SIADH failed to dilute their urines and remained hyponatremic during 48 and 110 h of saline infusion. CONCLUSIONS The authors demonstrate appropriate stimulation of ADH in RSW. Differences in plasma renin and aldosterone levels and FEphosphate can differentiate RSW from SIADH, as will persistent hypouricemia and increased FEurate after correction of hyponatremia in RSW. FEphosphate was the only contrasting variable at baseline. The authors suggest an approach to treat the hyponatremic patient meeting criteria for SIADH and RSW and changing CSW to the more appropriate term, RSW
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Affiliation(s)
- Solomon Bitew
- Division of Nephrology and Hypertension and Department of Medicine, Winthrop-University Hospital, Mineola, New York, USA
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Liamis G, Christidis D, Alexandridis G, Bairaktari E, Madias NE, Elisaf M. Uric acid homeostasis in the evaluation of diuretic-induced hyponatremia. J Investig Med 2007; 55:36-44. [PMID: 17441410 DOI: 10.2310/6650.2007.06027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Diuretics are one of the most common causes of severe hyponatremia. The responsible pathogenetic mechanisms remain unclear. Serum uric acid concentration has been proposed as an index of differentiating between two pathophysiologic constructs of diuretic-induced hyponatremia-extracellular volume depletion and syndrome of inappropriate antidiuretic hormone secretion (SIADH)-like state-but its discriminating value has not been verified in large series of patients. Here we attempt to illuminate the pathophysiology of diuretic-induced hyponatremia by focusing on uric acid homeostasis. Additionally, we analyze the epidemiology and clinical characteristics of the disorder. METHODS We studied prospectively 158 adult patients with hyponatremia on admission to our internal medicine clinic. Here we report on those with diuretic-induced hyponatremia. RESULTS Forty patients (13 male and 27 female) had diuretic-induced hyponatremia, rendering it the most common cause of the disorder (25.3%). These patients had lower mean ([Na+]) (121.2 +/- 7.2 vs 126.4 +/- 4.1 mEq/L, p = .0001) than the remaining hyponatremic patients. Patients with serum uric acid levels < 4 mg/dL (n = 14) exhibited a biochemical profile consistent with a SIADH-like state, whereas patients with serum uric acid levels > or = 4 mg/d (n = 26) were consistent with extracellular volume depletion. CONCLUSIONS Diuretics are the most common cause of community-developed hyponatremia. The serum uric acid level effectively discriminates between two biochemical profiles of diuretic-induced hyponatremia, one consistent with extracellular volume depletion and another that simulates SIADH.
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Affiliation(s)
- George Liamis
- Department of Internal Medicine, Medical School, University of Ioannina, Ioannina, Greece
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Bairaktari ET, Kakafika AI, Pritsivelis N, Hatzidimou KG, Tsianos EV, Seferiadis KI, Elisaf MS. Hypouricemia in individuals admitted to an inpatient hospital-based facility. Am J Kidney Dis 2003; 41:1225-32. [PMID: 12776275 DOI: 10.1016/s0272-6386(03)00355-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Decreased serum uric acid levels resulting from renal urate wasting occasionally are reported in hospitalized patients because of isolated or generalized proximal tubular damage. There are limited recent findings with regard to the incidence and cause of hypouricemia in patients admitted to an internal medicine clinic. The aim of this study is to examine the prevalence of hypouricemia in individuals admitted to our inpatient hospital-based facility and identify underlying causes and pathogenetic mechanisms and any association of hypouricemia and uricosuria with other tubular defects. METHODS A total of 7,250 serum urate measurements were available on patients' admission. Hypouricemia is defined as a serum urate level less than 2.5 mg/dL (149 micromo/L). In all hypouricemic cases, a detailed clinical and laboratory investigation was performed. RESULTS Hypouricemia was found in 90 patients (1.24%). In all except one patient, hypouricemia was associated with inappropriate uricosuria (urate fractional excretion [FE] > 10%; range, 10.8% to 94%). There was an inverse correlation between serum uric acid level and its FE (r = -0.73; P < 0.0001). The most common causes of hypouricemia were obstructive jaundice of any cause (n = 18), solid or hematologic neoplasias (n = 17), diabetes mellitus (n = 12), drugs affecting urate homeostasis (n = 10), and intracranial diseases (n = 8). Seventeen patients with hypouricemia showed one or more other manifestations of proximal tubular damage, such as glucosuria, inappropriate phosphaturia leading to hypophosphatemia, and kaliuria resulting in hypokalemia. CONCLUSION Hypouricemia caused by inappropriate uricosuria is not rare in patients admitted to an internal medicine clinic, is related to underlying diseases, and may be associated with other abnormalities of proximal tubular function.
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Affiliation(s)
- Eleni T Bairaktari
- Department of Internal Medicine, University Hospital, University of Ioannina, Medical School, Ioannina, Greece
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Maesaka JK, Wolf-Klein G, Piccione JM, Ma CM. Hypouricemia, abnormal renal tubular urate transport, and plasma natriuretic factor(s) in patients with Alzheimer's disease. J Am Geriatr Soc 1993; 41:501-6. [PMID: 8486882 DOI: 10.1111/j.1532-5415.1993.tb01885.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To study tubular urate transport in Alzheimer's disease (AD) and measure sodium and lithium transport rates in rats exposed to AD plasma. DESIGN Cross-sectional study in three comparison groups. SETTING Referral private institution involving outpatient and hospitalized patients. PATIENTS AD, multi-infarct dementia (MID) and non-demented controls (C) were selected and evaluated by a geriatrician and a psychiatrist according to availability and willingness to participate in the study. Demented patients had brain imaging, categorized according to NINCDS-DSM III criteria, and had Mini-mental status examination (MMSE) scores determined. INTERVENTIONS Injection of 0.5 mL of plasma I.P. followed 120 minutes later by an IV plasma injection of 0.2 mL priming dose and infusion of 1.8 mL of plasma at 0.01 mL/min in Sprague Dawley rats. MEASUREMENTS Renal clearance studies were performed in subjects and in rats exposed to the plasma of study subjects. We measured serum urate concentration and fractional excretion (FE) of urate in subjects and FE sodium and FE lithium in rats. RESULTS Serum urate was lower and FE urate higher in 18 AD patients compared with six patients with MID, P < 0.05 and P < 0.005, and 11 C, P < 0.02 and P < 0.005, respectively. Higher FE sodium and FE lithium were noted in rats given plasma from 19 AD patients compared with 12 with MID, P < 0.005 and P < 0.0025, and 14 C, P < 0.0025 and P < 0.0005, respectively. FE sodium and FE lithium decreased progressively after serial dilutions of three AD plasmas and FE lithium was negatively correlated with MMSE scores only in AD, r = -0.71 and P < 0.0005. CONCLUSIONS In AD there is defective tubular urate transport and a plasma natriuretic factor(s). FE sodium and/or FE lithium in rats exposed to plasma of demented patients may differentiate AD from MID and estimate the severity of AD.
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Affiliation(s)
- J K Maesaka
- Division of Nephrology, Long Island Jewish Medical Center, New Hyde Park, NY 11042
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12
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Affiliation(s)
- R J Riese
- Center for Mineral Metabolism and Clinical Research University of Texas Southwestern Medical Center, Dallas 75235
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Decaux G, Prospert F, Namias B, Schlesser M, Soupart A. Raised urea clearance in cirrhotic patients with high uric acid clearance is related to low salt excretion. Gut 1992; 33:1105-8. [PMID: 1398236 PMCID: PMC1379451 DOI: 10.1136/gut.33.8.1105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In cirrhotic patients without renal failure, salt retention could result from a decreased effective intravascular volume or could be a primary event leading to increased intravascular volume. Clearance of urea and uric acid depend on an effective intravascular volume. In the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)--a state of increased intravascular volume--uric acid clearance is increased and that of urea is increased only when salt excretion is low. The intravascular volume of 60 consecutive cirrhotic patients without renal failure was estimated indirectly by studying the relationship between fractional excretion of filtered (FE) sodium, urea, and uric acid. Forty five per cent had a high FE uric acid (> 12%), which could mean a high intravascular volume, and presented with an FE urea that was inversely correlated with FE sodium (r = 0, 62; p < 0.001) as in SIADH, while in the controls the FE urea was positively correlated with FE sodium (r = +0, 46; p < 0.01). In patients who had a normal FE uric acid and low FE sodium (< 0.2%), the FE urea was significantly lower (40 (13)%, n = 20) than in subjects with high FE uric acid and a low FE sodium (61 (9)%, n = 16, p < 0.001); this last group also presented with lower mean blood urea concentrations (3.1 (1.2) mmol/l and 4.0 (1.8) mmol/l; p < 0.05) and a lower supine renin activity (p < 0.01). As observed in the SIADH, cirrhotic patient with high FE uric acid have raised FE urea only when salt excretion is low. It is believed that the low salt excretion is not caused by a decrease in effective intravascular volume and that this is increased in cirrhotic patients with raised FE uric acid.
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Affiliation(s)
- G Decaux
- Department of Internal Medicine, University Hospital Erasme, Free University of Brussels, Belgium
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Abstract
In a population of 27 consecutive patients with liver cirrhosis, systemic hemodynamics were investigated and correlated to uric acid concentrations, fractional uric acid excretion, and creatinine clearances. Mean serum uric acid concentration was lower than in normal controls, and this was related to abnormally high uric acid clearances. Uric acid concentrations correlated positively to total peripheral resistances and negatively to cardiac output. Fractional uric acid excretions correlated negatively to total peripheral resistances and positively to cardiac output. There was no correlation between creatinine clearances and any variable of systemic hemodynamics. Serum uric acid concentration and fractional uric acid excretion are dependent of the hemodynamic state in cirrhosis.
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Roch-Ramel F, Weiner IM. Renal excretion of urate: factors determining the actions of drugs. Kidney Int 1980; 18:665-76. [PMID: 6780719 DOI: 10.1038/ki.1980.184] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Lang F, Greger R, Oberleithner H, Griss E, Lang K, Pastner D, Dittrich P, Deetjen P. Renal handling of urate in healthy man in hyperuricaemia and renal insufficiency: circadian fluctuation, effect of water diuresis and of uricosuric agents. Eur J Clin Invest 1980; 10:285-92. [PMID: 6775956 DOI: 10.1111/j.1365-2362.1980.tb00035.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To differentiate between extrarenal and renal causes of hyperuricaemia and gout, clearances of urate and creatinine were monitored for 3 1/2 days in fifty-two individuals (seven with a history of gout) with no gross impairment of renal function (creatinine clearance 52-137 ml/min). Dietary purine intake was kept constant. Monophasic circadian fluctuations of fractional urate excretion (= urate clearance over creatinine clearance) were observed with peak values in the afternoon, about 50% higher than during the night. Circadian fluctuations of urinary flow rate were almost identical. However, enhancement of urinary flow rate due to water diuresis had no effect on urate clearance. Despite wide variation of plasma urate concentrations among different individuals (+/- 30% SD), daily urate excretion varied little (+/- 4% SD) and did not correlate with plasma urate (r = 0.03). Thus extrarenal factors appear not to account for the occurrence of hyperuricaemia in these patients. In contrast, a clearcut negative correlation was apparent between plasma urate concentration and fractional urate clearance (r = 0.72), which could fully account for the variations of plasma urate concentration. To elucidate further the mechanism responsible for antiuricosuria in hyperuricaemic patients, the effects of the uricosuric agents benzbromarone and probenecid were tested. A clearcut correlation was apparent between control fractional urate excretion and uricosuric effect of both benzbromarone and probenecid (r = 0.83 and 0.88, respectively), suggesting that anti-uricosuria was due to defective secretion. In an additional series, the uricosuric effect of probenecid was tested in ten patients with renal insufficiency. In these patients the uricosuric effect was clearly blunted, indicating that urate reabsorption is reduced in renal insufficiency.
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Dunlop W, Furness C, Hill LM. Maternal haemoglobin concentration, haematocrit and renal handling of urate in pregnancies ending in the births of small-for-dates infants. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1978; 85:938-40. [PMID: 570055 DOI: 10.1111/j.1471-0528.1978.tb15857.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In nine patients who gave birth to babies below the fifth centile in weight, serum urate concentration and fractional reabsorption of urate were significantly higher than in 25 control patients whose babies were of normal birth weight. Haemoglobin concentration and haematocrit were also significantly increased in the small-for-dates group. All of these changes may reflect depletion of extracellular fluid volume.
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Lang F, Greger R, Deetjen P, Knox FG. Factors affecting urate reabsorption in the rat kidney. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1977; 76B:100-9. [PMID: 16453 DOI: 10.1007/978-1-4684-3285-5_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Urate transport in the rat appears to be saturable. However, affinity of the transport system for urate is very low and transport far from saturated at physiological plasma concentrations. 2. Since increase of the nonionized fraction of uric acid by a factor of five failed to increase urate reabsorption, transport cannot be due to nonionic diffusion but rather involves ionized urate. 3. Increases in luminal flow rate markedly depress urate reabsorption in the loop of Henle, which results in wash out of medullary urate.
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Abstract
These results are consistent with a model for renal tubular transport of urate in which there is reabsorption of both filtered and secreted urate. Urate secretion greatly exceeds total urate excretion, and most secreted urate is reabsorbed. At least a portion of urate reabsorption occurs at a site distal to or coextensive with the urate secretory site. There appear to be at least two distinct reabsorptive mechanisms for urate. The results of the flow rate and vasopressin studies are consistent with the hypothesis that urate reabsorption occurs in both the distal and the proximal tubule in man. The distal reabsorptive site appears to be quite small. It may be passive since it does not appear to be inhibited by uricosuric drugs. This reabsorptive site may account for less than 15% of total urate reabsorption. Both volume expansion and probenecid may inhibit urate absorption only in the proximal tubule. Thus reabsorption in the proximal tubule coud account for more than 90% of total urate reabsorption. Reabsorption at the postulated collecting duct reabsorptive site appears to be too small in magnitude to account for all reabsorptions of secreted urate. This could be explained if the reabsorptive site in the proximal tubule is coextensive with or distal to the secretory site. Alternatively, there might be two reabsorptive sites in the proximal tubule: a presecretory site accounting for the reabsorption of most filtered urate, and a site either coextensive or distal to the secretory site accounting for a major component of reabsorption of secreted urate. Finally urate reabsorption would also take place in the collecting duct, perhaps at a passive, flow-dependent site.
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