<abstract xmlns="http://www.w3.org/1999/xhtml"><bold>Introduction:</bold> The aim of the study is to present a case study of a 63-year-old male with pseudohyponatremia, falsely increased serum osmolal gap and severe metabolic acidosis.<bold>Material and Methods:</bold> Venous whole blood (direct sodium selective electrode measurement) and serum (indirect sodium selective electrode measurement) were used to measure sodium concentration. Serum cholesterol, triacylglycerides and total protein were measured to confirm pseudohyponatremia. Base excess in extracellular fluid and serum bicarbonate concentrations were employed as markers of metabolic acidosis. Serum protein electrophoresis and free light chain analysis were used for the detection of paraproteins.<bold>Results:</bold> Venous whole blood acid base analysis showed a pH of 7.171, negative base excess in extracellular fluid of – 18.6 mmol/L and sodium concentration of 140 mmol/L. Serum test measurement revealed serum sodium concentration of 130 mmol/L, osmolal gap of 24 mmol/kg, creatinine concentration of 702 µmol/L, HCO3- concentration of 6.1 mmol/L and total protein concentration of 134.9 g/L. Serum paraprotein IgG kappa with a concentration of 86 g/L and a serum free light chains kappa/lambda ratio of 223.5, along with the final diagnosis of multiple myeloma were detected. Toxic alcohol ingestion was considered, both methanol and ethylene glycol tests were negative.<bold>Conclusions:</bold> High paraprotein concentrations in serum may lead to pseudohyponatremia when measured by indirect ion selective electrodes. Multiple myeloma frequently leads to renal failure with metabolic acidosis.</abstract>

Introduction: The aim of the study is to present a case study of a 63-year-old male with pseudohyponatremia, falsely increased serum osmolal gap and severe metabolic acidosis.Material and Methods: Venous whole blood (direct sodium selective electrode measurement) and serum (indirect sodium selective electrode measurement) were used to measure sodium concentration. Serum cholesterol, triacylglycerides and total protein were measured to confirm pseudohyponatremia. Base excess in extracellular fluid and serum bicarbonate concentrations were employed as markers of metabolic acidosis. Serum protein electrophoresis and free light chain analysis were used for the detection of paraproteins.Results: Venous whole blood acid base analysis showed a pH of 7.171, negative base excess in extracellular fluid of – 18.6 mmol/L and sodium concentration of 140 mmol/L. Serum test measurement revealed serum sodium concentration of 130 mmol/L, osmolal gap of 24 mmol/kg, creatinine concentration of 702 µmol/L, HCO3- concentration of 6.1 mmol/L and total protein concentration of 134.9 g/L. Serum paraprotein IgG kappa with a concentration of 86 g/L and a serum free light chains kappa/lambda ratio of 223.5, along with the final diagnosis of multiple myeloma were detected. Toxic alcohol ingestion was considered, both methanol and ethylene glycol tests were negative.Conclusions: High paraprotein concentrations in serum may lead to pseudohyponatremia when measured by indirect ion selective electrodes. Multiple myeloma frequently leads to renal failure with metabolic acidosis.

Pseudohyponatremia and falsely increased serum osmolal gap caused by paraprotein in a patient with severe metabolic acidosis – a case study

Czech Republic Biomedical Sciences, University of Ostrava, Faculty of Medicine

Revista Romana de Medicina de Laborator

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Introduction: The aim of the study is to present a case study of a 63-year-old male with pseudohyponatremia, falsely increased serum osmolal gap and severe...

Pseudohyponatremia and falsely increased serum osmolal gap caused by paraprotein in a patient with severe metabolic acidosis – a case study

Published Online: Apr 27, 2021

Page range: 229 - 233

Received: Mar 15, 2021

Accepted: Apr 06, 2021

DOI: https://doi.org/10.2478/rrlm-2021-0017

Keywords
pseudohyponatremia, hyponatremia, acidosis, paraproteins, multiple myeloma

© 2021 Tomáš Šálek, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Pseudohyponatremia and falsely increased serum osmolal gap caused by paraprotein in a patient with severe metabolic acidosis – a case study

Published Online: Apr 27, 2021

Page range: 229 - 233

Received: Mar 15, 2021

Accepted: Apr 06, 2021

DOI: https://doi.org/10.2478/rrlm-2021-0017

Keywordspseudohyponatremia, hyponatremia, acidosis, paraproteins, multiple myeloma

© 2021 Tomáš Šálek, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
pseudohyponatremia, hyponatremia, acidosis, paraproteins, multiple myeloma