Potassium

Question 1

ECG changes in hyperK:

Answer 1

1- Peaked T
2- PR prolong
3- Flat P wave
4- Bradyarrythmias (sinus brady, blocks, escapes)
4- Widening QRS
5- Sine

Question 2

ECG changes in HyPOK:

Answer 2

Bigger P waves
T wave flattening/inversion
ST depression + U waves
QT prolongation

Question 3

Hyperkalaemia Management:

Answer 3

We want to “C BIG K Drop”
_________________________

Calcium gluconate
–> (cardioprotection)

Beta agonists
Bicarb (if acidotic)
Insulin
Glucose
–> (Intracell shift)

Kayexelate/ Resonium (polystyrene)
Diuretics (K wasting: eg. frusemide)
Dialysis
–> Excretion

Question 4

Classify hyperkalaemia:
- Mild
- Mod
- Severe

Answer 4

Mild > 5.2
Mod >6
Severe >7

Question 5

What ECG changes would you expect for what K levels?

Answer 5

5-6: T waves
6-7: P waves, PR
7-9: Bradys, blocks, widening
9+: …..Sine wave, asystole/ VF.

Question 6

Causes of HYPERkalaemia:

Answer 6

INPUT
- Medication error
- Iatrogenic

PRODUCTION
- TLS
- Crush
- Rhabdo
- Burns
- Ischaemia
- Haemolysis

LOSSES
- Renal failure (non-diuresing, chronic)
- Missed dialysis
- HyPOaldolsteronism
–> Primary, Addisons
- K-sparing medication
–> Spirinolactone, ACE, ARB

SHIFT
- Acidosis

OTHER
- Digoxin
- Sux

Question 7

Causes of HYPOkalaemia:

Answer 7

INPUT
- Starvation
- Anorexia
- Iatrogenic

LOSSES
- Sweating ++
- Burns
- Vomiting, diarrhoea, laxatives
- Fistula, stoma
- Diuresis
- Dialysis

SHIFT
- Alkalosis
- Beta agonists
- Insulin

OTHER
- Mg depletion
- Hyperaldosteronism
–> Conn’s, Licorice, Renin-producing tumour< Bartter/ Liddle

Question 8

ECG in HYPOkalaemia:

Answer 8

No ECG changes until mod/sev (<3)

T wave flattening, TWI
U wave
ST depression
QT prolongation –> Torsades
VT/ VF

Question 9

Management of life-threatening HYPOkalamia:

Answer 9

• RESUS
• CVC +-
• 10-20mmol K over 10mins
  or
• 0.5mmol/kg/hr (less urgent)
  +
• MgSO4

_____________

RATE is about cardiac safety, CONC is about need for CVC
—> In emergency, fine to run minibags peripherally if monitored. If fluid restricted, will need concentrated- CVC

________
If Mg low, K will be refractory to replacement (exac. ongoing renal wasting)

Question 10

Calcium: General
- Metabolism
- Functions

Answer 10

Vit D
–> Intestinal absorption

PTH
–> Renal resorption
–> Vit D synthesis
–> Release from bone

Calcitonin
–> Tones it down- regulatory
–> Inhibits the above

______________________
Muscle contraction (incl smooth muscle- vessels, bronchs)
Inotrope
Coagulation
Neurotransmitter release

Question 11

Symptoms of hypercalcaemia:

Answer 11

Stones, bones, psychic groans, abdominal moans

Neuropsych
Hyporeflexia, weakness
Dehydration+
Renal stones
Bradyarrythmia, AV block, AF, VT
Bone pain

Question 12

Management of hypercalcaemia:

Answer 12

Excrete/ stop resorption
- Fluids
- Frusemide
- Haemodialysis

Inhibit mobilisation:
- Bisphosphonate
–> Eg. Pamidronate 90mg IV
- Calcitonin

Other
- Correct K, Mg
- Med rec
- Treat cause