Potassium and electrolytes010921

Question 1

What are the stimuli for aldosterone secretion

Answer 1

angiotensin II

potassium

Question 2

causes of hypercalaemia

Answer 2

o	1. reduced GFR 
o	2. reduced Renin
 - 	T4 RTA (diabetic nephropathy)
 -       NSAIDs
o	3. ACE inhibitors
o	4. ARBs (Angiotensin 2 Receptor Blockers)
o	5. Addison’s disease
o	6. Aldosterone antagonists (i.e. spironolactone)

Question 3

RAAS system

Answer 3

o Angiotensinogen converted to Ang-1 [LIVER via renin from JGA]; renin release via…
 Low BP (in renal artery)
 Low Na+ in macula dense by JGA
 SNS beta-1 receptor activation
o Ang-1 converted to Ang-2 [LUNGS via ACE]
o Ang-2 acts on the adrenals to release aldosterone
o Aldosterone excretes K+ and increases Na+ retention
o Trigger for aldosterone release:
 Angiotensin II
 Potassium (high)

Question 4

How do you treat hyperkalaemia

Answer 4

10ml 10% calcium glucoronate
100ml 20% dextrose
salbutamol

Question 5

Causes of potassium loss

Answer 5

GI loss 
renal loss (hyperaldosteronism, increased sodium delivery to distal nephron, osmotic diuresis)
redistribution into the cells (insulin, beta agonists, alkalosis)

Question 6

How would you manage a patient with hypokalaemia in serum potassium 3-3.5

Answer 6

serum potassiumm 3-3.5 mmol/L

- oral potassium chloride (2 SandoK tablets tds for 48 hrs)

Question 7

How would you manage a patient with hypokalaemia <3.0mmol/L

Answer 7

<3.0mmol/L
 IV KCl
 Maximum rate 10mmol/hour (rate >20mmol/hour  irritate peripheral veins)

Question 8

Clinical signs of hypokalaemia

Answer 8

o Muscle weakness
o Cardiac arrhythmias (ECG = ST depression, flat T-waves, U waves)
o Polyuria and polydipsia (nephrogenic DI from low K+ or a high Ca2+)

Question 9

aldosterone leads to potassium loss or gain?

Answer 9

loss