What are the key clinical features to assess in a patient with suspected hyponatremia?

When assessing a patient with suspected hyponatremia, key clinical features to evaluate include the severity and onset of symptoms, neurological status, volume status, and potential underlying causes. Neurological assessment is critical because hyponatremia can cause symptoms ranging from mild confusion, headache, nausea, and vomiting to severe manifestations such as seizures, reduced consciousness, and coma, reflecting cerebral oedema risk ¹ (Hoorn and Zietse, 2008). Volume status assessment helps differentiate between hypovolemic, euvolemic, and hypervolemic hyponatremia, guiding management; signs include orthostatic hypotension, tachycardia, peripheral oedema, ascites, and jugular venous pressure ¹ (Martín-Llahí et al., 2006). History and examination should focus on recent fluid losses (vomiting, diarrhoea), medication use (diuretics, antidepressants), comorbidities (heart failure, liver cirrhosis, renal disease), and symptoms suggestive of endocrine disorders (e.g., hypothyroidism, adrenal insufficiency) ¹ (Sumi et al., 2025). Severity and acuity of hyponatremia influence clinical presentation; acute drops in sodium often cause more pronounced neurological symptoms than chronic hyponatremia ¹ (Hoorn and Zietse, 2008). Additional features such as signs of infection or systemic illness should also be assessed to identify precipitating factors ¹. This integrated clinical evaluation is essential to guide appropriate investigations and treatment decisions in hyponatremia management.