Urea and Electrolytes

Question 1

What is the use of measuring creatinine blood concentration?

Answer 1

It is specific for determining kidney injury

Question 2

What are some causes of changes in urea?

Answer 2

Non-specific
High urea - Dehydration, GI bleed, increase protein breakdown (surgery/trauma/infection/malignancy), high protein intake or drugs.
Low urea - Malnutrition, liver disease and pregnancy,

Question 3

List some causes of hyponatremia

Answer 3

• Diuretics,
• Addison’s disease,
• Diarrhoea/vomiting,
• Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH),
• Hypothyroidism,
• Congestive HF,
• Hypalbuminaemia

Question 4

What are some causes of hypernatremia?

Answer 4

• Hypovolaemia causing low urine output,
• Cushing’s disease
• Iatrogenic

Question 5

What are some causes of hypokalaemia?

Answer 5

• Increased renal excretion (Diuretics, Cushing’s disease, renal tubule acidosis)
• Intestinal fluid loss (Diarrhoea/vomiting),
• Increased cellular uptake (Alkalosis, insulin and salbutamol)

Question 6

What are some causes of hyperkalaemia?

Answer 6

• Reduced renal excretion (Kidney injury, drugs, Addison’s disease).
• Excessive K+ load (iatrogenic or massive blood transfusion),
• Increased cellular release (acidosis)

Question 7

What are some causes of hypocalcaemia?

Answer 7

• Increased renal excretion,
• PTH related,
• Increased deposition/reduced uptake (bisphosphonates or vitamin D deficiency)

Question 8

What are some causes of hypercalcaemia?

Answer 8

• Reduced renal excretion,
• Increased release from bones,
• Excess PTH,
• Excessive vitamin D

Question 9

What are the stages of AKI?

Answer 9

Stage 1 - Serum cretinine over 1.5x baseline
Stage 2 - Serum creatinine over 2x basline
Stage 3 - serum creatinine over 3x baseline or over 354