Symptomatic hypotonic hyponatremia presenting at high altitude

Wilderness Environ Med. 2014 Mar;25(1):69-74. doi: 10.1016/j.wem.2013.09.014. Epub 2014 Jan 8.


We present a case of altered mental status and seizure that occurred at an altitude known to cause high altitude-related illnesses. Based on the presenting symptoms, the patient was initially transferred to the hospital with a presumptive diagnosis of high altitude cerebral edema. On review of imaging and laboratory data, she was found to be experiencing symptomatic hypotonic hyponatremia. This case presented an interesting diagnostic challenge and underscores the importance of maintaining a broad differential diagnosis when evaluating a patient with altered mental status from an alpine setting.

Keywords: exertional associated hyponatremia (EAH); high altitude cerebral edema; hypertonic saline (HTS); hyponatremia; search and rescue; syndrome of inappropriate antidiuretic hormone (SIADH).

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Altitude
  • Brain Edema / diagnosis
  • Brain Edema / etiology
  • California
  • Diagnosis, Differential
  • Female
  • Humans
  • Hyponatremia / diagnosis*
  • Hyponatremia / drug therapy
  • Hyponatremia / etiology*
  • Saline Solution, Hypertonic / therapeutic use
  • Sodium / blood


  • Saline Solution, Hypertonic
  • Sodium