Hyponatremia is the most common electrolyte disturbance seen in hospital practice. Severe hyponatremia can be life threatening and is associated with considerable mortality.
To assess the prevalence of severe hyponatremia (plasma Sodium <120 mmol/l) by retrospective analysis in a hospital population and its laboratory investigation, management and clinical outcome.
Over a six-month period 77 patients (men 50: women 27) were identified with severe hyponatremia. The mean patient age was 73+14 years. The mortality rate was 27%. 70% of patients were admitted through medical speciality. The mean initial plasma sodium concentration was 116+4 mmol/l. The mean rate of rise of sodium was 3.06+3 mmol/l in 24 hours. Collapse or falls is the commonest cause of admission. 5% were on SSRI, 38% of patients were on diuretics, 8% were postoperative. Serum osmolality was measured in 32% % of patients, 27% had urine osmolality, 10% had urinary sodium measured. 42% had thyroid function tests, 92% had liver function tests. 13% had tests to exclude hypoadrenalism. 32% of patients were fluid restricted and 5% of patients were treated inappropriately with 5% dextrose
Severe hyponatremia, although rare is a serious abnormality commonly seen in elderly population admitted to the hospitals. Local guidelines in investigation and management of hyponatremia may help in optimising patients care.
1. Reynolds RM, Padfield PL & Seckl JR. Disorders of sodium balance. BMJ 2006 332 (7543) 702705.
2. Reynolds RM & Seckl JR. Hyponatraemia for the clinical endocrinologist. Clin Endocrinol (Oxf) 2005 63 (4) 366374.
06 - 07 Nov 2006
Society for Endocrinology