Hyponatraemia — a serum sodium concentration below 135 mmol/l — becomes an acute management priority when it presents with neurological and constitutional symptoms. The pattern of confusion, headache, or persistent nausea without vomiting defines a moderately severe clinical picture that warrants immediate, structured treatment.
Serum sodium <135 mmol/l with moderately severe symptoms: nausea without vomiting, confusion, or headache. This degree of symptom burden is present at any biochemical level of hyponatraemia and signals the need for prompt intervention.
Management combines addressing the underlying cause with an immediate intravenous hypertonic saline intervention — administered as a single infusion — followed by close sodium monitoring at defined intervals. The complete infusion protocol, correction-rate limits, and monitoring schedule are contained in the full regimen.
The aim is a controlled rise in serum sodium of 5 mmol/l per 24 hours, continuing until a serum sodium of 130 mmol/l is reached — with care taken to avoid overcorrection.