title: Exertional dysnatremia in collapsed marathon runners: a critical role for point-of-care testing to guide appropriate therapy.
abstract: Dysnatremia may cause life-threatening encephalopathy in marathon runners. Hypernatremia and exercise-associated hyponatremia (EAH) may manifest with mental status changes and, if untreated, progress to coma and death. We reviewed the on-site blood sodium testing and treatment in collapsed runners at the finish-line medical tent at the Boston marathons from 2001 through 2008. Dysnatremia was diagnosed in 429 (32.5%) of 1,319 collapsed runners. Hypernatremia was present in 366 (27.7%) and hyponatremia in 63 (4.8%). Hypernatremic runners unable to drink fluids were treated with intravenous normal (0.9%) saline. Hyponatremic runners with seizures or coma received intravenous hypertonic (3%) saline. Sixteen runners with EAH able to drink a concentrated oral hypertonic solution recovered within 30 minutes. Based on on-site sodium testing, dysnatremic runners were treated with appropriate intravenous fluids according to validated standards of care. Hyponatremic runners able to drink an oral hypertonic solution recovered promptly.
authors.affiliation: McLean Hospital, Belmont, MA, USA.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Siegel
authors.forename: Pierre
authors.initials: P
authors.lastname: d'Hemecourt
authors.forename: Marvin M
authors.initials: MM
authors.lastname: Adner
authors.forename: Terry
authors.initials: T
authors.lastname: Shirey
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Brown
authors.forename: Kent B
authors.initials: KB
authors.lastname: Lewandrowski
mesh_terms: D001927:Brain Diseases / Q000097:blood / Q000209:etiology / Q000628:therapy; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D006955:Hypernatremia / Q000097:blood* / Q000628:therapy*; D007010:Hyponatremia / Q000097:blood* / Q000628:therapy*; D019095:Point-of-Care Systems; D017410:Practice Guidelines as Topic; D012420:Running