Electrolyte abnormalities

Question 1

What is main cause of hypernatraemia

Answer 1

HYPOVOLAEMIC: DEHYDRATION

• elderly and not drinking sufficiently
• GI loss / sweat loss
• diabetes insipidus

if euvolaemic > increase in sodium:

• Medical high intake (hypertonic saline, sodium bicarb)
• Conns
• RAS

Question 2

How do you manage hypernatramemia

Answer 2

IV DEXTROSE 5% 1L/6-8h

remember serial sodium measurements every. 6h

Question 3

What are compolications of hypernatraemia

Answer 3

rapid correction: cerebral oedema

Question 4

How do you manage HYPOnatraemia

Answer 4

HYPOVOLAEMIC
- dehydrated > give 0.9% NaCl

EUVOLAEMIC/HYPERVOLAEMIC
- fluid restrict (e.g. 500ml per day) + treat underlying cause

Question 5

What is a danger in correcting hyponatraemia top quickly

Answer 5

cerebral pontine myelinolysis

Question 6

What are hyperkalaemic changes on ECG

Answer 6

Tall and tented T waves
Broad QRS
Flat P wave
Prolonged PR interval (bradycardia)

Question 7

What are symptoms of hyperkalaemia

Answer 7

muscle weakness and cramps

paraesthesia

Question 8

causes of hyperkalaemia

Answer 8

Insuff renal K+ excretion

1. Low GFR (CKD/AKI)
2. Low renin (T4 RTA, NSAIDS)
3. ACEi
4. ARB

Excess K+ release from cells

• rhabdomyolisis
• acidosis

Question 9

Management of hyperkalaemia

Answer 9

1. 10% 10ml calcium gluconate over 10 mins
2. 10U Actrapid insulin in 100ml 20% dextrose over 30 mins
3. 5mg salbutamol nebulised STAT
4. Treat underlying caus e
5. Repeat K+ in 6 hours
   * * if treatment resistant, discuss with renal team re dialysis

Question 10

What are causes of hypokalaemia

Answer 10

EXCESS K+ loss

• GI LOSSES (diarrhoea, vomiting, fistulas)
• RENAL LOSS

K+ drive into cells

• insulin, insulinoma
• alkalosis

Question 11

How do you manage hypokalaemia

Answer 11

Mild (3.5-3): SandoK BD
Moderate (3-2.5): IV KCl 40mmol /1L / 6hours
Severe (<2.5) IVKCl 40mmol /1L / 4hours