Clinical Chemistry🥼 Flashcards
what is hyponatraemia
serum sodium concentration<135mmol/L
what are the 3 categories of causes of hyponatraemia
hypovolaemic
euvolaemic
hypervolaemic
hypovalaemic causes of hyponatraemia
burns
sweating
diarrhoea
vomiting
fistulae
addisons
diuretic use
euvolaemic causes of hyponatraemia
SIADH
hypothyroidism
hypervolaemic causes of hyponatraemia
renal failure
heart failure
liver failure
nephrotic syndrome
ix hyponatraemia
may be a clear cause but if cause is unknown number of tests required to exclude SIADH:
U&Es
urine and plasma paired osmolalities
urine sodium
urine dip
TSH & cortisol
mx of hypovolaemic hyponatraemia
IV normal saline
treat underlying cause
mx euvolaemic hyponatraemia
SIADH - fluid restriction
hypothyroidism - levothyroxine
mx hypervolaemic hyponatraemia
fluid restriction
treat underlying cause
complications of treating hyponatraemia
if sodium is corrected too fast, risk of central pontine myelinosis is increased
how to determine if a hyponatraemia is true or pseudo
measure serum osmolality
true - hypo-osmolar
pseudo - iso-osmolar/hyperosmolar
in the patient is unwell due to their hyponatraemia e.g having seizures then what do you do
hypertonic (3%) saline can be given
how to calculate an estimated serum osmolality
2(sodium+potassium) + glucose + urea
what monitoring should hyponatraemic pts undergoing fluid resuscitation other than sodium and other electrolyte levels
urine output
causes of pseudohyponatraemia
hyperlipidaemia
paraproteinaemia as seen in multiple myeloma, high blood glucose levels and use of mannitol or glycine
