hyponatraemia Flashcards
broad subtypes of hyponatraemia
hypovolaemic, euvolaemic, hypervolaemic hyponatraemia
ddx for hypovolaemic hyponatraemia (6)
epithelial surface fluid loss
- diarrhoeal illness
- burns
- vomiting
drugs
- thiazide diuretics
endocrine
- hypopituitarism
- primary adrenal insufficiency
ddx for euvolaemic hyponatraemia
SIADH - drugs - cerebellar pathology - malignancy secondary adrenal insufficiency hypothyroidism
psychogenic polydipsia
pain
nausea
ddx for hypervolaemic hyponatraemia
CKD
CCF
Liver cirrhosis
nephritis syndrome
define hyponatraemia
< 135mmol/L
define severe hyponatraemia
< 120mmol/L
how to examine extracellular volume status in hyponatraemmia
- blood pressure (lying, standing)
- presence of oedema
- jugular venous pressure
- pulse rate
- skin turgor
- mucous membrane hydration
diagnostic criteria for SIADH
serum Na+ < 130mmol/L
serum osmolality < 275
urine osmolality > 100
urine sodium > 30
what is SIADH, and brief description of its effect
syndrome of inappropriate anti-diuretic hormone secretion
- excess ADH secretion
- water gets retained in body
- electrolytes are lost (mainly sodium)
- > hyponatraemia with high urine salt content
hyponatraemia - indications for hospital management
Na+ < 120mmol/L
hyponatraemia with cerebral signs
hyponatraemia - outpatient management
- address the cause of hyponatraemia
- patient to monitor fluid input, urine output
- fluid restriction
day 1 - 0.8-1.2L in 24 hours
day 2+ - urine output - 500mL - daily review with UECs
hyponatraemia treatment - target correction rate
10mmol/24h
18mmol/48h
neurological symptoms of hyponatraemia
- altered conscious state
- dizziness
- seizure