Pseudohyponatremia Revisited: A Modern-Day Pitfall

Fortgens, Philip; Pillay, Tahir S

doi:10.5858/2010-0018-rs.1

Cited by 64 publications

(20 citation statements)

References 15 publications

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“…But in current clinical practice, most of the laboratories use indirect potentiometry using an ion-selective electrode that has a sodium selective membrane, which measures the potential generated across a sodium selective membrane, when immersed in a serum sample [ 5 , 11 ]. The potential generated is a function of the activity of sodium ions in the sample [ 5 , 7 , 11 ]. The activity of an element is described as a measure of the number of atoms that act completely as ions per unit volume of electrolyte solution [ 12 ].…”

Section: Discussionmentioning

confidence: 99%

“…In pseudohyponatremia, the water component is diluted by non-aqueous materials such as lipids and proteins. In conditions like hyperlipidemia and hyperproteinemia, abnormally high levels of these large molecules replace the aqueous phase of plasma, thus resulting in a reduced amount of serum electrolytes per unit volume of serum [ 6 , 7 ]. When measured with conventional flame photometry or indirect potentiometry, which involves prior dilution of the samples, the measured sodium concentration is low but the true plasma concentration is normal [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…In conditions like hyperlipidemia and hyperproteinemia, abnormally high levels of these large molecules replace the aqueous phase of plasma, thus resulting in a reduced amount of serum electrolytes per unit volume of serum [ 6 , 7 ]. When measured with conventional flame photometry or indirect potentiometry, which involves prior dilution of the samples, the measured sodium concentration is low but the true plasma concentration is normal [ 7 ]. Not being aware of this artifact and correction of sodium in these conditions result in increased morbidity and mortality [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

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Pseudohyponatremia Leading to a Fatal Outcome in a Patient With Familial Hypertriglyceridemia

Dawson¹,

Kanukuntla²,

Kata³

et al. 2021

Cureus

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Serum sodium assay is a commonly performed laboratory test in a clinical setting and the results are taken for granted without being aware of the actual methods involved. In conditions like hyperlipidemia and hyperproteinemia, excessive lipids in serum dilute the water component of the serum. Since sodium is dissolved only in the aqueous phase of serum, the sodium content per unit volume of plasma is reduced. Currently, most of the laboratories use the indirect ion-selective electrode method (ISE), where the plasma sample is diluted before the measurement. Indirect ISE may not give accurate results in conditions with higher serum lipid and protein levels. Overcorrection of the serum sodium levels in pseudohyponatremia may cause serious complications. We report a case of a 26-year-old Asian male with a past medical history of chronic pancreatitis, familial hypertriglyceridemia, and fatty liver who presented to the emergency department with acute pancreatitis. Initially, the patient was found to have hyponatremia and he was started on hypertonic saline for one day. Later the patient’s condition deteriorated and then it was determined that serum sodium results were a measurement artifact since the patient had extremely high levels of triglycerides. After realizing that it was a measurement artifact, the saline infusion was stopped and he was started on desmopressin. However, the patient deteriorated neurologically and expired later. As this patient had normal sodium levels, administration of hypertonic saline led to a fatal outcome.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pseudohyponatremia Leading to a Fatal Outcome in a Patient With Familial Hypertriglyceridemia

Dawson¹,

Kanukuntla²,

Kata³

et al. 2021

Cureus

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“…So pseudohyponatremia or pseudonormonatremia should be ruled out. [10][11][12] So, there is an advantage with direct ISE method because results are unaffected by the presence of abnormal protein and lipid content, whereas indirect ISE results get affected. 13,14 Chow et al showed that hypoproteinemia may lead to reporting of falsely high Na + values by indirect ISE method.…”

Section: Discussionmentioning

confidence: 99%

Effect of Hypoproteinemia on Electrolyte Measurement by Direct and Indirect Ion Selective Electrode Methods

2021

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Objective The aim of this study was to see the effect of hypoproteinemia on electrolyte measurement by two different techniques, that is, direct ion selective electrode (ISE) and indirect ISE. Material and Method It was an observational study in which 90 serum samples with normal protein content (Group-1) were subjected to sodium (Na+) and potassium (K+) measurements by direct and indirect ISE methods. In the same way, 90 serum samples with total protein < 5 g/dL (Group-2) were subjected to Na+ and K+ measurements by direct and indirect ISE methods. Result In samples from Group-1 patients, average Na+ was 138.1 ± 4.764 mmol/L by direct ISE method and 139.3 ± 3.887 mmol/L by indirect ISE method while average K+ was 4.41 ± 0.644 mmol/L by direct ISE method and 4.40 ± 0.592 mmol/L by indirect ISE method. There was no statistically significant difference in Na+ and K+ values measured by different methods. In samples from Group-2 patients, measured value of Na+ by direct ISE and indirect ISE was 134.57 ± 5.520 mmol/L and 138.64 ± 5.401 mmol/L, respectively. Difference between these two values was statistically significant with p-value of < 0.0001, but direct ISE and indirect ISE measured values of K+ was 4.146 ± 0.9639 mmol/L and 4.186 ± 0.8989, respectively, with no significant difference. Conclusion Direct and indirect ISE methods are not comparable and showing significantly different results for Na+ in case of hypoproteinemia. So, it is recommended that setups like intensive care unit or emergency department, where electrolyte values have significant treatment outcome, should follow direct ISE method and should compare its previous result with the same method. Both the methods should not be used interchangeably.

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“…It involves direct potentiometry and is used in point-of-care blood gas analyzers. The second method is indirect ISE, which is used in routine chemistry analyses in central laboratories, and it includes a pre-analysis serum or plasma dilution step [8,9].…”

Section: Discussionmentioning

confidence: 99%

Pseudohyponatremia in a neuroblastoma patient with obstructive jaundice and review of literature

Bassi¹,

Manzitti²,

Montalto³

et al. 2021

Clin Case Rep Rev

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Background: Pseudohyponatremia is uncommonly associated with severe hypercholesterolemia. Case presentation: We report a case of pseudohyponatremia in a pediatric patient with severe hypercholesterolemia caused by obstructive jaundice. A 20-month-old female was hospitalized following a diagnosis of abdominal neuroblastoma related to asymptomatic hyponatremia.Results: This is the first pediatric report of falsely low sodium levels in a child with severe hypercholesterolemia caused by abdominal neuroblastoma mass-related obstructive jaundice. At presentation we observed asymptomatic hyponatremia (126 mmol/L; normal range: 135-145 mEq/L), while she was later found to have 16.7 mg/dl total bilirubin and 870 mg/dL total serum cholesterol (normal range: 80-180 mg/dL). Pseudohyponatremia was diagnosed and confirmed by direct potentiometric measurement of serum osmolality (279 mOsm/kg; normal range: 275-290 mOsm/kg) and serum sodium (135 mmol/L), performed on a blood gas analyzer. It is unusual to observe an association of pseudohyponatremia with severe hypercholesterolemia. Conclusion:We report that extreme hypercholesterolemia in cholestasis may actually be a rare cause of pseudohyponatremia. This underscores the need to carry out serum sodium evaluation with direct potentiometry when extreme hypercholesterolemia is present, and how important it is to achieve a differential diagnosis between pseudohyponatremia and hyponatremia prior to starting treatment, especially in the pediatric setting.

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Pseudohyponatremia Revisited: A Modern-Day Pitfall

Cited by 64 publications

References 15 publications

Pseudohyponatremia Leading to a Fatal Outcome in a Patient With Familial Hypertriglyceridemia

Pseudohyponatremia Leading to a Fatal Outcome in a Patient With Familial Hypertriglyceridemia

Effect of Hypoproteinemia on Electrolyte Measurement by Direct and Indirect Ion Selective Electrode Methods

Pseudohyponatremia in a neuroblastoma patient with obstructive jaundice and review of literature

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