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Abstract: FR-PO289

No Added Salt…The Epidemiology of Severe Hyponatraemia in a Tertiary Referral Hospital

Session Information

Category: Fluid and Electrolytes

  • 902 Fluid and Electrolytes: Clinical


  • Mcgrath, Susan, Mater Misericordiae University Hospital, Dublin, Ireland
  • Moloney, Brona, Mater Misericordiae University Hospital, Dublin, Ireland
  • Moore, Dean Stephen, Mater Misericordiae University Hospital, Dublin, Ireland
  • O'Meara, Yvonne M., Mater Misericordiae University Hospital, Dublin, Ireland
  • O'Riordan, Aisling, Mater Misericordiae University Hospital, Dublin, Ireland
  • McGing, Peadar, Mater Misericordiae University Hospital, Dublin, Ireland
  • Sadlier, Denise M., Mater Misericordiae University Hospital, Dublin, Ireland

Severe hyponatremia is defined as a serum sodium concentration less than or equal to 120mmol/L and can be associated with mild symptoms (e.g. decreased concentration) to more severe life-threatening symptoms (e.g. seizures and coma). Patients with severe symptomatic hyponatraemia should be managed with hypertonic saline to correct their serum sodium and reduce the morbidity and mortality associated with this condition. In this retrospective study, the aetiology, management and outcomes of severe hyponatraemia were examined over a 5-year period


All patients admitted to a tertiary referral hospital with serum sodium ≤120mmol/L were identified through the biochemistry laboratory database from January 2013 – December 2017 inclusive. Patient data was extracted from hospital records and included age, gender, presenting complaint, co-morbidities, medications, clinical exam findings, treatment received, laboratory results, length of stay, nephrology consult and in-hospital mortality.


A total of 592 patients met the inclusion criteria, 46.7% (n=277) were male, 24.8% (n=147) were aged >80years. The commonest causes were hypovolaemia (30%, n=178), hypervolaemia (15%, n=89), Syndrome of Inappropriate ADH secretion (13.7%, n=81) and medication induced (15%, n=89), of which thiazides were the most common. The most common symptoms were falls (17.2%, n = 102), confusion (11.6%, n=69) and GI upset (9.7%, n=58). 7.2% (n=43) presented with seizures. Hypertonic saline was indicated in 26.2% (n=155) of cases, but of these only 19.4%(n=30) have it documented as part of their treatment, 5% of total cases. Of the patients who presented with seizure, only 16.3% (n=7) received hypertonic saline. Average length of stay for these patients was 25days. Mortality for an admission complicated by severe hyponatremia was 14% (n=84), with a one year mortality of 27.4% (n=162).


Severe hyponatraemia is associated with significant symptoms, length of stay and 1-year mortality. Hypertonic saline is indicated in the treatment of severe symptomatic hyponatraemia and is proven to be a safe therapy, but only a minority of patients received this important treatment. Further education is required in order to improve the management and outcomes in this patient group.