Electrolyte Imbalance

Question 1

Common causes of hypernatraemia?

Answer 1

Fluid losses without replacement

• Diarrhoea
• Incorrect IV fluid replacement
• Diabetes insipidus
• Osmotic diuresis

Salt retention/ingestion

• Primary aldosteronism (Conn’s)
• Ingestion table salt, IVI NaHCO3
• Increased glucocorticoids (cushings), ectopic ACTH

Question 2

What are the two types of diabetes insipidus?

Answer 2

Central

Nephrogenic

Question 3

How to management hypernatraemia?

Answer 3

Stop ongoing water losses

Correct water deficit

Correct sodium deficit if hypovolaemic

Question 4

What is the normal K?

Answer 4

3.5-5

Question 5

What are some causes of hyperkalaemia?

Answer 5

Excessive exogenous K load

• K supplements

Excession endogenous K load

• Rhabdomyolysis (K release from cell death)
• Tumour lysis syndrome
• Haemolysis

Redistribution

• Lactic acidosis (K is swapped for H)
• Hyperglycaemia (insulin deficiency)

Diminished K excretion

• Acute or chronic renal failure
• Drugs

Question 6

How does heparin impact K levels?

Answer 6

Increases it by aldosterone suppression, natriuresis and reduced K secretion

Question 7

What are the ECG changes with hyperK

Answer 7

Peaked T waves

Widened QRS

Sine wave QRS

Question 8

How do you manage hyperkalaemia?

Answer 8

Correct serious conduction abnormalities

• Calcium chloride (10%, 10mL)
• Calcium gluconate (10%, 10mL)
• Mg

Drive K into the cell

• Insulin (rapid) and glucose (avoid hypo)
• Sodium bicarbonate
• Salbutamol (beta-agonist > draw K into cell)

Eliminate K from the body

• Resonium - decrease gut absorption
• Frusemide
• Normal saline (flush it out)
• Dialysis

Question 9

How does hyperkalaemia present?

Answer 9

Muscle weakness

Arrhythmia

Cardiac arrest