Clinical features

• Early features of EAH include: nausea, vomiting, headache, bloating, tissue puffiness
  
  
• Later features of EAH include: confusion, disorientation, seizures, coma, pulmonary oedema

As the severity of EAH progresses, more clinical features of hyponatremic encephalopathy can develop as a result of cerebral oedema (brain swelling), including alteration of mental status (eg, confusion, disorientation, agitation, delirium), seizures, respiratory distress (pulmonary edema), obtundation, coma and death

Usually individuals are asymptomatic symptoms until Na+ < 130 mmol

As many as 10% of ultra distance runners might be hyponatraemic (1)

Contributors (September 2010):

• Dr Volker Scheer (GP Locum), Dr Andrew Murray (Marathon Medical Services)

Reference:

• 1) Hew-Butler T, Ayus JC, Kipps C, Maughan RJ, Mettler S, Meeuwisse WH, Page AJ, Reid SA, Rehrer NJ, Roberts WO, Rogers IR, Rosner MH, Siegel AJ, Speedy DB, Stuempfle KJ, Verbalis JG, Weschler LB, Wharam P.Statement of the Second International Exercise-Associated Hyponatremia Consensus Development Conference, New Zealand, 2007. Clin J Sport Med. 2008 Mar;18(2):111-21