hyponatraemia

Question 1

broad subtypes of hyponatraemia

Answer 1

hypovolaemic, euvolaemic, hypervolaemic hyponatraemia

Question 2

ddx for hypovolaemic hyponatraemia (6)

Answer 2

epithelial surface fluid loss

• diarrhoeal illness
• burns
• vomiting

drugs
- thiazide diuretics

endocrine

• hypopituitarism
• primary adrenal insufficiency

Question 3

ddx for euvolaemic hyponatraemia

Answer 3

SIADH
- drugs
- cerebellar pathology
- malignancy
secondary adrenal insufficiency
hypothyroidism

psychogenic polydipsia
pain
nausea

Question 4

ddx for hypervolaemic hyponatraemia

Answer 4

CKD
CCF
Liver cirrhosis
nephritis syndrome

Question 5

define hyponatraemia

Answer 5

< 135mmol/L

Question 6

define severe hyponatraemia

Answer 6

< 120mmol/L

Question 7

how to examine extracellular volume status in hyponatraemmia

Answer 7

• blood pressure (lying, standing)
• presence of oedema
• jugular venous pressure
• pulse rate
• skin turgor
• mucous membrane hydration

Question 8

diagnostic criteria for SIADH

Answer 8

serum Na+ < 130mmol/L
serum osmolality < 275
urine osmolality > 100
urine sodium > 30

Question 9

what is SIADH, and brief description of its effect

Answer 9

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

Question 10

hyponatraemia - indications for hospital management

Answer 10

Na+ < 120mmol/L

hyponatraemia with cerebral signs

Question 11

hyponatraemia - outpatient management

Answer 11

• 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

Question 12

hyponatraemia treatment - target correction rate

Answer 12

10mmol/24h

18mmol/48h

Question 13

neurological symptoms of hyponatraemia

Answer 13

• altered conscious state
• dizziness
• seizure