title: [Pseudohyponatremia and anion gap changes in multiple myeloma].
abstract: Pseudo-hyponatremia is a rare condition characterized by a decrease in plasma sodium concentration associated with a normal or increased effective plasma osmolarity. We present the case of a 62 year old woman with multiple myeloma (IgG) who had a plasma sodium of 84.5 mEq/l (as measured with flame photometry) and an anion gap of -8.8 mEq/l. However, when determined with an ion-selective electrode, plasma sodium was 135 mEq/l. The patient was treated with chemotherapy and did not receive sodium. One week later, plasma sodium--again measured by flame photometry--was 134 mEq/l and the anion gap 4.0 mEq/l. The pathophysiological and clinical aspects of pseudo-hyponatremia and the anion gap are discussed.
authors.forename: A
authors.initials: A
authors.lastname: Valdivieso
authors.forename: M
authors.initials: M
authors.lastname: Costa
authors.forename: X
authors.initials: X
authors.lastname: Robino
authors.forename: T
authors.initials: T
authors.lastname: Quiroga
authors.forename: P
authors.initials: P
authors.lastname: Bertin
mesh_terms: D000136:Acid-Base Equilibrium; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000150:complications* / Q000503:physiopathology; D008875:Middle Aged; D009101:Multiple Myeloma / Q000150:complications*; D009994:Osmolar Concentration; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium
vernacular_title: Pseudo hiponatremia y cambios en el anion gap en un mieloma múltiple.