Lecture 3 - Assessing Renal Function in AKI

Question 1

Name the functions of the kidney

Answer 1

Regulation of extracellular fluid volume and blood pressure
regulation of blood osmolarity
Maintenance of ion balance
Homeostatic regulation of plasma pH
Excretion of metabolic and other wastes
Hormone activity
Activation of vitamin D
Production of erythropoietin
Production of urine
Production of renin
Regulation of electrolytes
Regulation of acid/base balance

Question 2

Define creatinine

Answer 2

a metabolic waste product of creatine metabolism in the muscles
it is higher in patients with higher muscle mass

Question 3

Name the 3 algorithms to measure kidney

Answer 3

Cockcroft and Gault Formula
Modification of diet in renal disease (MDRD)
CKD-EPI

Question 4

What is the most accurate measurement for kidney function?

Answer 4

CKD-EPI - so is used to monitor disease progression, classify and identify renal impairment in CKD

Question 5

What are the signs and symptoms of AKI?

Answer 5

Acidosis, oedema, reduced urine output, hyperkalaemia, toxicity of medicines with narrow therapeutic window. reduced urine output

Question 6

What are the common risk factors for AKI?

Answer 6

CKD, HF, liver disease, diabetes, previous AKI, oliguria, neurological impairment, hypovolaemia, physical disability, cognitive impairment, use of nephrotoxic drugs, sepsis and age over 65

Question 7

When is eGFR likely to be overestimated?

Answer 7

The elderly, those on a low protein diet, amputees, those with a muscle wasting disorder

Question 8

When is eGFR likely to be underestimated?

Answer 8

High muscle mass, high protein diet, muscle breakdown

Question 9

How to prevent an AKI in a hospital setting?

Answer 9

Hold ACEi/ARB should be discontinued on day of administration of bowel prep and consider withholding for 72 hours
Diuretics should be discontinued on day of administration of oral bowel preparations and withheld for 24 hours
monitor fluid balance - ensure good hydration
Withhold metformin in patients undergoing CT scans

Question 10

How should AKIs be managed?

Answer 10

Treat CAUSE
optimise medications - stop nephrotoxins, stop medications which exacerbate consequences of renal impairment
Review doses for other renally excreted drugs
Maintain good hydration
Treat electrolyte abnormalities and acidosis
Renal Impairment therapy if necessary