Scenario 18 - hyponatraemia

Question 1

What is the first question to ask yourself in a case of hyponatraemia?

Answer 1

Are they hyponatraemic/euvolaemic/hypervolaemic?

Question 2

Describe the urine sodium in hypovolaemic, euvolaemic and hypervolaemic hyponatraemia?

Answer 2

Hypovolaemia –> low urine sodium
Euvolaemia –> high urine sodium
Hypervolaemia –> low urine sodium

Question 3

Recall 3 causes of hypovolaemic hyponatraemia

Answer 3

Diuretics
Diarrhoea
Vomiting

Question 4

Recall 3 possible causes of euvolaemic hyponatraemia

Answer 4

These are ENDOCRINE

1. SIADH
2. Hypothyroidism
3. Adrenal insufficiency

Question 5

Recall 3 possible causes of hypervolaemic hyponatraemia

Answer 5

1. Cardiac failure (causes excess water)
2. Cirrhosis (causes renal insufficiency which in turn causes excess water)
3. Nephrotic syndrome

Question 6

Recall 5 drugs that may cause SIADH

Answer 6

SSRIs
TCAs
PPIs
Carbamazepine
Opiates