Renal replacement therapy

Question 1

Renal replacement therapy modalities

Answer 1

active treatment:
- dialysis - haemodialysis/peritoneal dialysis
- kidney transplantation

conservative management

Question 2

What is chronic kidney disease?

Answer 2

patients with reduced eGFR and/or urinary abnormalities detected on at least 2 occasions 3 months apart

Question 3

How can patients with eGFR>60 be considered to have CKD?

Answer 3

only if they have concomitant evidence of kidney damage:
- urinary abnormalities (proteinuria, haematuria)
- structural abnormalities (abnormal renal imaging)
- genetic disease
- histologically established disease

Question 4

CKD causes

Answer 4

T2DM
Hypertension
Glomerular diseases
Unknown
T1DM
Cystic/hereditary
Nephritis
Tumours

Question 5

Functions of the kidney

Answer 5

salt and balance
excrete waste products of metabolism
acid-base balance
erythropoietin secretion
activation of vitamin D
blood pressure control (fluid/renin secretion)
excrete drugs

Question 6

Complications of CKD

Answer 6

sodium retention + fluid overload
hyperkalaemia
metabolic acidosis
hyperphosphataemia, high PTH, hypocalcaemia, low calcitriol
anaemia

Question 7

How does haemodialysis work?

Answer 7

during dialysis blood is exposed to dialysate (with physiological conc of electrolytes) across a semi-permeable membrane

small molecules (urea, creatinine) and electrolytes pass through pores in membrane
large molecules (albumin, Igs) and blood cells do not

conc differences across the membrane allow molecules to diffuse down a gradient
waste products are removed and desirable products replaced

Question 8

What is needed for haemodialysis?

Answer 8

dialysis membrane
dialysate
effective control + safety mechanisms
vascular access
anticoagulation

Question 9

What is the optimal form of vascular access for haemodialysis?

Answer 9

fistula (radiocephalic, brachocephalic, brachobasilic)

Question 10

How often is haemodialysis needed?

Answer 10

3 times a week
4 hours each time

Question 11

How does peritoneal dialysis work?

Answer 11

solutes and fluid move between the fluid-filled peritoneum via 3 pore model:
- large pores allow macromolecules (protein) to be filtered

• small pores responsible for transport of small solutes (sodium, potassium, urea, creatinine)
• ultra small pores transport water alone (aquaporin 1)

Question 12

Advantages of peritoneal dialysis

Answer 12

preservation of residual function
no need for vascular access
mobility (no dialysis centre needed for holidays)
patient engagement in treatment
home-based therapy - maintains independence
less expensive
lower risk of transmission of blood-borne viruses

Question 13

Contraindications to peritoneal dialysis

Answer 13

patient or carer unable to adequately train in technique
inguinal, umbilical or diaphragmatic hernias
ileostomy/colostomy
abdominal wall/intra-abdominal infections
previous extensive surgeries/radiotherapy (adhesions/fibrosis)

Question 14

Renal transplantation benefits

Answer 14

improved survival
improved quality of life
more physiological and complete correction of uraemic milieu, anaemia, and mineral bone disease (secondary hyperparathyroidism)
improved sexual function + fertility - chance for successful pregnancy
economics - cheaper in long term

Question 15

How long does a living donor kidney function on average?

Answer 15

12-20 years

Question 16

How long does a deceased donor kidney function on average?

Answer 16

8-12 years