ELECROLYTE ABNORMALITIES

Question 1

Low potassium treatment

Answer 1

Mild:

• Sando K PO
• Daily measurement of serum K

Moderate/severe (<2.5)

• 0.9% NaCl plus 40mmol KCL over 4h
• Cardiac monitoring
• Senior review/advice

Question 2

Hyperkalaemia treatment

Answer 2

1. Calcium gluconate IV
2. Insulin plus dextrose

Recheck K on VBG/bloods

Can also give nebulised salbutamol (10-20mg)

Question 3

Hyponatraemia assessment

Answer 3

Assess serum osmolality FIRST to determine whether it is a true hyponatraemia

• Low sodium and low osmolality - true hyponatraemia
• Low sodium and normal osmolality - pseudo-hyponatraemia
• Low sodium and increased osmolality could be due to HHS

Then assess fluid status:

• Hypovolaemic e.g. diuretics, burns, D+V
• Euvolaemic - can be due to SIADH
• Hypervolaemic - likely CCF, low albumin (e.g. liver disease, nephrotic syndrome), or renal failure

Then check urine sodium/osmolality to see if it is a kidney problem:
- High urine sodium or osmolality - shows loss of sodium is from kidneys

Question 4

Hyponatraemia treatment

Answer 4

Hypovolaemic - 0.9% saline

Hypervolaemic - treat underlying cause

Euvolaemic - Check plasma and urine osmolality and sodium, may require fluid restriction if SIADH suspected

Severe hyponatraemia - can consider hypertonic saline - but would want senior advice

Question 5

Why can’t sodium be corrected quickly?

Answer 5

Can cause central pontine myelinolysis

Na should not rise by >6mmol/L in the first 6hrs or >10mmol in the first 24hrs

Question 6

What is central pontine demyelination?

Answer 6

Extravascular volume becomes concentrated – fluid drawn from brain and osmotic balance in myelin becomes disrupted

This causes demyelination of neurones

Can cause:

• Acute paralysis
• Speech/swallowing
• Mortality

Question 7

Hypernatraemia treatment

Answer 7

Oral rehydration

5% dextrose - Na shouldn’t be corrected by >10mmol/L in 24h

Check glucose - could be due to HHS

Hold diuretics and laxatives

Check urine osmolality - could be Diabetes insipidus

Question 8

Hypercalcaemia signs and symptoms

Answer 8

Thirst
Polyuria
Anorexia
Nausea
Constipation
Confusion
Renal Stones
Peptic ulcers
Muscle weakness

Question 9

Hypercalcaemia treatment

Answer 9

Treat underlying cause

0.9% NaCl

IV pamidronate can be given (20mg/hr (30-90mg))

Question 10

Hypocalcaemia signs and symptoms

Answer 10

Paraesthesia
Muscle cramps
Chvostek’s sign
Trousseau’s sign
Convulsions
Palpitations
Arrythmias

Question 11

Hypocalcaemia treatment

Answer 11

Mild - Adcal D3

Severe or symptomatic:
- 10ml 10% calcium gluconate in 100ml 5% Dextrose over 10mins