Hyponatraemia.


< 135mmol/l.

Usually chronic in GP.

Most often euvolaemic, hypo-osmolar hyponatraemia.


Risk factors

  • Old age / renal disease / hospitalisation /female.


Causes

  • Medications - diuretics, SSRIs, opiods, NSAIDs, antipsychotics
  • CHF / CLF /CRF / Hypothyroidism
  • Dehydration - sport, infirmity.
  • Excessive hydration - polydipsia, ecstacy, iv fluids
  • SIADH - esp small cell lung ca.
  • Adrenal insufficiency - Addisons, 



> 125 correct, slowly

< 125 - admit


Assessment

  • Water load status  - euvolaemic, hypovolaemic, hypervolaemic.
  • Check Serum osmolality (n > 275)
  • Check urinary Na+ and urinary osmolality.