Acute Kidney Injury and the Overview of Renal Diseases

Question 1

What is Acute Kidney Injury (AKI)?

Why is it an important problem?

Answer 1

• An abrupt/sudden decrease in kidney function, normally due to illness, drugs, or injury. It results in the build up or urea and other nitrogenous waste products, like ammonia. There will be a rise in urea and creatinine due to the quick decline in GFR, and there will be a loss of water and solute homeostasis. However, AKI is REVERSIBLE.
• High mortality rate and expensive.

Question 2

What are the factors involved in producing the glomerular filtrate?

How do ACEi and ARBs affect glomerular filtration?

Answer 2

• • High perfusion pressure and renal blood flow
  • Pressure gradient across Bowman’s capsule
• Vasodilate efferent arteriole = ↓pressure gradient = ↓Glomerular filtration

Question 3

What are the four indications for initiating RRR (renal replacement therapy, like dialysis)?

Answer 3

1. Hyperkalaemia
2. Acidaemia
3. Pulmonary Oedema
4. Uraemia (High blood [urea]) - can lead to encephalopathy

Question 4

What is Polyuric AKI?

Answer 4

The excessive/abnormal production of urine due to an abrupt decrease in renal function (AKI).

This only occurs in some cases as a result of a disturbance in tubular reabsorption. Na+ stays in filtrate, so water moves into it = ↑↑Urine output.

Question 5

What are the main functions of the Kidney?

Answer 5

1. Excrete waste substances
2. BP controlRegulate ECF minerals
3. Acid-base balance
4. Water balance
5. RBC production - erythropoietin
6. Vitamin D activation
7. Regulate ECF minerals

Question 6

What are the types of causes of Kidney Disease?

Answer 6

• Pre-renal causes – Hypovolaemia, ↓Perfusion, Drug toxicity
• Intrinsic renal disease – Glomerular disease, Nephritis, Necrosis (measure the urine Albumin:Creatinine and Protein:Creatinine ratios)
• Post-renal causes – Obstruction and stones in the kidney/ureter, causing hydronephrosis/hydroureter.

Question 7

How is AKI classified?

Which stage requires RRT?

Answer 7

• Put into 3 stages, depending on their Serum Creatinine levels and Urine output
• Only Stage 3 AKI requires Renal Replacement Therapy

Question 8

How is AKI managed?

How will it be treated?

Answer 8

• • Relieve any obstruction and correct any pre-renal factors.
  • Maintain fluid and electrolyte balance.
  • Gastric protector drugs given, being careful with what’s being prescribed, and avoiding sepsis
• • Treat underlying condition and endocrine issues
  • Slowly control BP
  • For Stage 3 AKI, RRT is given (e.g. dialysis, transplant)

Question 9

What are the 2 types of dialysis and outline their mechanisms

Answer 9

1. Haemodialysis: dialysate is flowing in opposite direction to blood. It removes the waste, corrects the electrolytes and acid-base balance by diffusion through a semi-permeable membrane.
2. Peritoneal Dialysis: substances are exchanged between the peritoneal fluid and blood. The dialysate is pumped into the peritoneal cavity, diffusion of the substances occurs, and the dialysate is drained out.

Question 10

Describe the complications associated with Chronic Kidney Disease (CKD)?

Answer 10

• CKD is recognised as a marker for cardiovascular disease - leads to ↑ECFV, calcification, anaemia.
• Poor survival rate as age increases for patients needing RRT.