Renal Replacement Therapy

Question 1

What does the term renal replacement therapy encompass?

Answer 1

All forms of dialysis and transplantation.

Question 2

What are the indications for dialysis?

Answer 2

BASED ON BLOODS: Resistant hyperkalaemia, GFR < 7, urea > 40, unresponsive acidosis
BASED ON SYMPTOMS: fatigue, itch, unresponsive fluid overload (pulmonary and peripheral oedema etc), nausea, vomiting, loss of appetite

Question 3

Is there any benefit to starting dialysis early?

Answer 3

No

Question 4

Describe how dialysis works?

Answer 4

Uses principles of diffusion from solutes moving to high to low concentration
Allows removal of toxins and infusion of bicarbonate
As patient has lots of K, urea and Na these diffuse out and bicarbonate diffuses in
Water is removed in haemodialysis by negative pressure filtration/ convection

Question 5

Minimum haemodialysis?

Answer 5

4hrs 3x a week

increases can increase survival but issues with QOL

Question 6

GFR provided by a dialysis machine is? How does this compare to healthy individual GFR?

Answer 6

Dialysis GFR = 10-12

Normal GFR = at least 60

Question 7

2 ways to get access for haemodialysis?

Answer 7

Arteriovenous Fistula

Tunneled venous catheter

Question 8

What is the gold standard of dialysis access?

Answer 8

Arteriovenous fistula

Question 9

Describe what an arteriovenous fistula is?

Answer 9

Joining of an artery and vein in the arm usually to make an enlarged thick wall vein allowing good vascular access for haemodialysis

Question 10

Pros and cons of arteriovenous fistula?

Answer 10

Pros: good blood flow and less likely to cause infection
Cons: Requires surgery, requires maturation of about 6 week before use, can limit blood flow to the distal arm

Question 11

Describe what a tunnelled venous catheter is?

Answer 11

A catheter is inserted into a large vein e.g. jugular, subclavian or femoral

Question 12

Pros and cons of a tunnelled venous catheter?

Answer 12

Pros: easy to insert and can be used right away
Cons: High risk of infection, untreated infection can lead to endocarditis, discitis and death. Can also cause damage to the veins making replacement difficult and the catheters can become blocked.

Question 13

Describe infection of tunnelled venous catheter?

Answer 13

High risk of infection particularly by Staph A. If untreated can lead to endocarditis, discitis and death. Often presents as rigors on dialysis.

Question 14

How does infection of tunnelled venous catheter often present?

Answer 14

Rigors on dialysis

Question 15

Rigors on dialysis?

Answer 15

Infection of tunnelled venous catheter

Question 16

Describe restriction for dialysis patients?

Answer 16

Fluid: If anuric 1 litre per day (including food based fluid)
Salt: Low salt diet to reduce thirst and help with fluid balance
Potassium: low potassium diet no bananas, chocolates, potatoes, avocado
Phosphate: low phosphate diet, phosphate binders with meals (6-12 pills per day), no diet coke!

Question 17

Describe 5 complications of dialysis?

Answer 17

Fluid overload
Blood leaks and exsanguination due to needle that returns blood to arm being dislodged but large volumes of blood still being removed from patient
Loss of vascular access
Hypokalaemia and cardiac arrest
Intradialytic hypotension: removing large volumes of fluid at once vs small volumes constantly

Question 18

Describe how peritoneal dialysis work?

Answer 18

Peritoneal membrane is used as a filter, solute removal is by diffusion of solutes across the peritoneal membrane. Water removal is by osmosis and is driven by high glucose concentration in the dialysate fluid.

Question 19

If a dialysis patient is fluid overloaded?

Answer 19

Don’t give them diuretics- they can’t pee so won’t work

Need dialysis done

Question 20

Is peritoneal dialysis as efficient as haemodialysis?

Answer 20

No

Question 21

Describe the two types of peritoneal dialysis?

Answer 21

CAPD (contiguous ambulatory): 4 bag exchanges per day, fluid drained then fresh fluid instilled. 1/2 hr per exchange.
APD (automated): 1 bag of fluid stays in all day and overnight machine drains in and out fluid for 9-10 hrs per night.

Question 22

3 complications of peritoneal dialysis?

Answer 22

Infection- peritonitis due to contamination or gut bacteria translocation
Membrane Failure- due to sugary solution, patient becomes fluid overloaded as can’t remove enough water, this requires switch to haemodialysis
Hernias- due to increased intrabdominal pressure

Question 23

Is there a survival difference between PD and HD?

Answer 23

No pretty much the same overall
If younger an fitter PD may be better in the beginning
Haemodialysis probably better for older patients

Question 24

Sign someone has had a kidney transplant?

Answer 24

Scar in iliac fossa and a mass

Question 25

Why do a kidney transplant vs dialysis?

Answer 25

Survival and quality of life is better Transplant allows freedom from fluid and diet restrictions Anaemia is corrected

Question 26

What does transplant surgery involve?

Answer 26

Anastamosis of an explanted human kidney either from deceased or living donor on the iliac vessels of the recipient. Ureter from the donor is placed into recipient bladder. Tend to leave old non functioning kidneys in. Unless donor is genetically identical then need life long immunosuppression. Donors generally come to no harm

Question 27

What happens if blood group is not compatible in a transplant?

Answer 27

Acute vascular rejection

Question 28

``` O donor can donate to ___1_____ O recipient can receive __2____ A recipient can receive ____3_____ AB recipient can receive ____4_____ B recipient can receive _____5_____ ```

Answer 28

1) any group 2) only from O 3) O or A 4) A, B, AB or O 5) B or O

Question 29

3 important HLA classes for matching in kidney transplant? Describe the matching?

Answer 29

HLA A HLA B HLA DR At each HLA A, B or DR there are 2 HLA types as have inherited one copy from each parent so there are loads of combinations overall.

Question 30

HLA typing is important as recipient could have donor specific antibodies, where might they have got these?

Answer 30

Blood transfusions Previous transplants Pregnancy

Question 31

4 types of transplant?

Answer 31

DBD - deceased brain dead DCD- deceased cardiac death Live donor kidney Kidney pancreas dual

Question 32

Describe a DBD transplant?

Answer 32

Patient has been declared brainstem dead, kidneys removed while person is technically still alive and kidneys go to most suitable match across UK.

Question 33

Describe a DCD transplant?

Answer 33

Patients who die at cardiac arrest but don't meet criteria for brain steam death but would die if ventilator turned off. They have to turn ventilator off and declare the person dead first as only allowed to remove the organs from DBD when alive. Usually these donors only donate kidneys and liver as other organs have not be perfused well enough. Organs are used by local centre due to prolonged ischaemia.

Question 34

Describe a live donor transplant?

Answer 34

Usually by sibling or parent but can be donated by other persons e.g. spouse under strict regulation

Question 35

Describe a kidney pancreas dual transplant?

Answer 35

Suitable for type 1 diabetics with kidney disease as replaces both kidney and pancreas function. Normal T1DM aren't given just pancreatic transplants due to equal risks associated with immunosuppression but if receiving a kidney may as well get a pancreas.

Question 36

Criteria for transplants?

Answer 36

Must have a life expectancy of 5 yrs or more Must be on dialysis or within 6 months of starting Allocation is based predominantly on tissue typing and then time on the waiting list

Question 37

Describe assessment of recipient of a kidney transplant?

Answer 37

Assess CVS risk: ECG, cholesterol, coronary angiogram, echo Virology: HBV, HCV, HIV, CMV, EBV all must be controlled/ treated before transplant CXR Bladder assessment Investigation of any co-morbidity

Question 38

7 Contraindications for kidney transplant?

Answer 38

Untreated malignancy History of solid tumour in last 2 yrs (5yrs for breast and colorectal) Untreated TB Severe IHD Severe Airways Disease Active Vasculitis that could recur in the transplant PVD- would be unable to attach diseased iliac artery to kidney

Question 39

Describe assessment of a live donor?

Answer 39

``` ECG CXR Virology GFR (measured fully) Quantification of proteinuria 24hr BP monitoring Renal angiogram X match against recipient ```

Question 40

3 types of rejection?

Answer 40

Hyperacute Acute Chronic

Question 41

Describe hyperacute rejection?

Answer 41

Occurs in minutes, already have antibodies to the kidney, unsalvageable and must remove kidney, usually due to wrong blood group

Question 42

Describe acute rejection?

Answer 42

T or B cell response, treated with immunosuppression

Question 43

Describe chronic rejection?

Answer 43

Immunological and vascular deterioration, difficult to treat

Question 44

3 groups of drugs used for immunosuppression?

Answer 44

Calcineurin inhibitors Purine Synthesis Inhibitors Steroids

Question 45

Calineurin inhibitors mechanism is _____ 2 examples are __________ Drug reactions are _________ Side effects are __________

Answer 45

Disrupt T cell signalling Cyclosporin and tacrolimus numerous as metabolised by cytochrome p450 renal dysfunction, hypertension, diabetes and a tremor

Question 46

Purine synthesis inhibitors mechanism is_______ 2 examples are _________ Drug reactions are __________ Side effects are ____________

Answer 46

suppression of proliferation of lymphocytes azathioprine and mycophenolate Allopurinol multiplies action of azathioprine 40x leucopenia, anaemia, GI side effects

Question 47

Steroids mechanism is __________ | Side effects are________

Answer 47

Suppress B cell proliferation and T cell activity | Osteoporosis, weight gain, infection, skin thinning and diabetes

Question 48

3 things that can happen post operation of kidney transplant?

Answer 48

Immediate graft function Delayed graft function- need haemodialysis whilst waiting for it to work Primary non-function

Question 49

Kidney transplant patients are usually discharged ______

Answer 49

1 week post surgery

Question 50

Describe follow up after kidney transplant?

Answer 50

``` long term check for acute and chronic rejection hypertension and CVD review UTIs Recurrent primary renal disease Surveillance for skin cancer ```

Question 51

4 reasons a graft may be lost?

Answer 51

Chronic rejection Toxicity of drugs Recurrent disease Ischaemia

Question 52

What happens if a patients transplant fails?

Answer 52

Go back on dialysis | If fit enough can get another kidney