Overview
Clinical Orientation
A low serum sodium is a water balance problem until proven otherwise, not automatically a sodium deficit problem.
A low serum sodium is a water-balance problem until proven otherwise, not automatically a sodium-deficit problem. Before choosing saline, establish whether the plasma is hypotonic, whether neurological symptoms indicate cerebral swelling, how long the abnormality has been present, and whether the kidneys are retaining or losing water. Correction has two competing hazards. Too little initial treatment can leave acute cerebral oedema untreated; too much treatment, or treatment delivered too quickly, can injure an adapted brain through osmotic demyelination. The practical goal is therefore not a normal sodium. It is prompt improvement in dangerous symptoms followed by a deliberately limited rise, with the entire correction trajectory tracked from the lowest pretreatment value. Severe symptomatic hyponatremia is an emergency for a monitored setting, with continuous neurological observation and frequent sodium measurement. In Canada, an NP’s authority to initiate, prescribe and titrate therapy is governed by the relevant provincial regulator, employer privileges, formulary and emergency protocols. Clinical urgency does not remove those jurisdictional and institutional requirements.
