Biochemistry

Question 1

What is the function of the kidneys?

Answer 1

• Regulate salt and water in the body (make urine)
• Remove waste products from blood into urine
• Produce hormones to regulate BP
• Create erythropoietin to control production of RBC’s
• Activate Vit D to keep bones healthy
• Help metabolise drugs

Question 2

What are the levels for AKI stage 1?

Answer 2

Serum creatinine - 1.5-1.9 baseline or >25umol/l increase

Urine output criteria - <0.5ml/kg/hr for 6-12 hours

Question 3

What are the levels for AKI stage 2?

Answer 3

Serum creatinine - 2 to 2.9x baseline

Urine output - <0.5ml/kg/hr for >12 hrs

Question 4

What are the levels for AKI stage 3?

Answer 4

Serum creatinine - >3x baseline or increase in serum creatinine >354umol/l
Urine output - <0.3ml/kg/hr for >24 hrs or anuria for >12 hrs

Question 5

What are the risk factors for an AKI?

Answer 5

• Age > 65 years
• History of AKI
• CKD
• Symptoms or history of urological obstruction
• Chronic conditions e.g. HF, liver disease, DM
• Sepsis
• Hypovolaemia
• Nephrotoxic drugs

Question 6

What is the first phase of ATN?

Answer 6

1. Oliguric phase
   Kidneys produce <500ml urine per day, vulnerable to fluid overload and electrolyte imbalance especially K and creatinine.

Question 7

What is the second phase of ATN?

Answer 7

2. Maintenance phase

Increased urinary output which helps maintain fluid and electrolyte balance.

Question 8

What is the third phase of ATN?

Answer 8

3. Polyuric recovery phase
   Kidneys produce large quantities of dilute urine so can lead to hypovolaemia.
   One cause is aquaporin channels in distal tubules and collecting ducts recover last so not as much waster reabsorbed and so high quantities of dilute urine produced. Decrease K and creatinine.