measurement of renal function

Question 1

Why measure renal function

Answer 1

1) identification of renal impairment in your patient

2) modification of dosages of drugs which are cleared by the kidneys

Question 2

What patients are at risk of renal failure

Answer 2

1) neonates and the elderly
2) polypharmacy
3) transplant patients
4) drug therapy
5) patients undergoing imaging procedures
6) specific disease states e.g. diabetes

Question 3

What are 3 ways of monitoring a patient’s renal function

Answer 3

1) patients clinical condition
2) modern imaging techniques
3) biochemical data e.g. sCr or BUN

Question 4

What factors affect plasma creatinine

Answer 4

Large muscle mass, some drugs e.g. cephalosporins,
ketoacidosis and ethnicity (increase)

reduced muscle mass, starvation, immobility, pregnancy and severe liver disease (decrease)

Question 5

What factors affect BUN

Answer 5

high protein diet, hypercatabolic conditions, GI bleeding, muscle injury, hypovolaemia (increase)

malnutrition, liver disease, sickle cell anaemia (decrease)

Question 6

What is renal clearance

Answer 6

the volume of plasma completely cleared of a given substance in unit time. compares the rate at which glomeruli filter a substance with the rate at which the kidneys excrete it via the urine.