Renal replacement therapy

Question 1

What are the symptoms that renal replacement therapy is usually started to manage?

Answer 1

• Hypervolaemia despite treatment
• Ureamia
• Refactory acidosis
• electrolyte abnormalities
• Pruritus
• cognitive impairment

Question 2

What is haemodialysis and how does it differ to haemofiltration?

Answer 2

Haemodialysis is when blood is passed over a semi permeable membrane with dialysis fluid flowing in the opposite direction. Diffusion allows solutes to move across and hydrostatic gradient is used to clear excess fluid
Haemofiltration is when water is cleared by positive pressure that drugs solutes into the waste by convection. This has a decreased risk of haemodynamic instability so can be used in ITU on patients who are not able to tolerate haemodialysis.

Question 3

What are the problems that can occur in haemodialysis/

Answer 3

Can have access problems e.g. fistula thrombosis, stenosis, infection of tunneled lines
Dialysis can cause cerebral oedema
Hypotension
Time consuming

Question 4

What problems occur in peritoneal dialysis?

Answer 4

Catheter site infection
Peritonitis
Peritoneal fibrosis
Membrane becomes less affective over time
Hernia

Question 5

How does dialysis cause infection other than directly through the acess sites?

Answer 5

Ureamia causes granulocyte and T cell dysfunction which leads to increased sepsis related mortality

Question 6

What are some of the other side effects of dialysis?

Answer 6

Causes:

• cardiovascular effects - increased BP, vascular stiffness, inflammation
• Bone effects - renal osteodystrophy and high bone turnover

Question 7

What are the absolute contraindications to kidney transplant?

Answer 7

Cancer with mets

Question 8

What are the temporary contraindications to kidney transplant?

Answer 8

Active infection, HIV with viral replication, unstable CVD

Question 9

What are the relative contraindications to renal transplant?

Answer 9

Congestive heart failure, CVD

Question 10

What are the types of graft for renal transplant?

Answer 10

Living donor - best function and survival
Deceased donor:
-Brainstem death
-Expanded criteria donor (poor quality kidney, better than dialysis
-Donor after cardiac death

Question 11

What drugs are used to reduce risk of rejection in renal transplant and how do they work?

Answer 11

• Monoclonal antibidies e.g. daclizumab selectively block T cells and are used at time of transplant to decrease chances of rejection
• Calcineurin inhibitors e.g. tacrolimus or ciclosporin are used to inhibit T cell activation
• Antimetabolites e.g. mycophenolic acid
• Glucocorticoids decrease the transcription of inflammatory cytokines

Question 12

What are some of the complications of renal transplant?

Answer 12

Surgical - bleed, infection, thrombosis
Delayed graft function - up to 40% of grafts
Rejection - acute or chronic
Infection
CVD - 3-5x increased compared to general population

Question 13

What are the types of renal transplant rejection? How is it treated?

Answer 13

There is acute rejection:
-Antibody mediated (rare)
-Cell mediated (most common)
-Treat with steroids and increased immunosupression
Chronic rejection is usually a reaction by donor specific antibodies