SIADH

Question 1

Where is ADH secreted from?

Answer 1

ADH (vasopressin) is secreted from the posterior pituitary

Question 2

What is the role of ADH?

Answer 2

Stimulates water reabsorption in the collecting ducts of the kidneys.

Question 3

What are the 2 sources of potential SIADH?

Answer 3

SIADH (syndrome of inappropriate ADH):

• Increased secretion from posterior pituitary
• Ectopic ADH secretion mostly from small cell lung cancer

Question 4

SIADH causes increased sodium concentration in the blood. True/false?

Answer 4

False, the increased water concentration dilutes the blood leading to decreased concentration of sodium in blood.

High sodium concentration in the urine.

Question 5

Non-specific symptoms of SIADH?

Answer 5

Headache
Muscle aches and pains
Fatigue
Confusion

Question 6

Causes of SIADH?

Answer 6

Malignancy - particularly small cell lung cancer
Lung abscesses
HIV

Question 7

What are some other causes of hyponatraemia (low sodium)?

Answer 7

CKD or AKI
Heart failure
Diuretic use
Excessive water intake