Dialysis and Transplantation Flashcards
Which toxins can dialysis remove that build up in end-stage kidney disease?
Urea
Potassium
Sodium
Creatinine
Which ion can be infused using dialysis?
Bicarbonate
List the components of dialysate
Pure water Sodium Bicarbonate Potassium Glucose
How is water removed from the body in dialysis?
Create negative pressure across membrane to suck water out (filtration)
Dialysis is very efficient. True/False?
False
Not very efficient; longer treatment equals better efficiency
What is the time schedule for haemodialysis?
4 hours, 3 times a week
How much fluid, salt, potassium and phosphate is allowed during dialysis?
Restrict fluid - 1 litre water a day
Low salt diet
Low potassium diet
Low phosphate diet and phosphate binders with meals
What is the gold standard for dialysis access?
Arteriovenous fistula, usually in arm joining brachial artery and cephalic vein
What are the drawbacks of an AV fistula?
Requires maturation of 6 weeks before use
Can limit blood flow to distal arm
Thrombosis/ stenosis
Creates a shunt
What is the alternative access for dialysis whilst the AV fistula is maturing?
Tunnelled venous catheter inserted into jugular/subclavian/femoral vein
What are the drawbacks of tunnelled venous catheters?
High risk of infection (usually SA endocarditis/ discitis)
Damage vein
Thrombosis/ stenosis
What can go wrong with dialysis?
Hypotension (underfilling of intravascular space due to removal of water)
Blood leaks
Reduced vascular access
Hyperkalaemia - cardiac arrest
What is the alternative to haemodialysis and how does it work?
Peritoneal dialysis
Use peritoneal membrane for diffusion of solutes, water removal by osmosis and glucose conc. in dialysate which drains into bag afterwards
What is the time schedule for peritoneal dialysis?
Continuous: 4 times a day
OR
Autonomous: Overnight (1 bag a day)
What is the advantage of peritoneal dialysis over haemodialysis?
Portable - less restrictive
What are the disadvantages of peritoneal dialysis?
Infection (peritonitis/ exit site due to contamination and gut bacteria translocation) Membrane failure (can't remove water causing fluid overload) Hernias (increased intrabdominal pressure)
When is dialysis started based on bloods?
Resistant hyperkalaemia
GFR less than 5 (following preparation!)
Unresponsive acidosis
Uraemia (UR >40)
Which syndrome can result in the short-term following haemodialysis?
Disequilibrium syndrome involving cerebral oedema and seizures
In end-stage kidney disease, survival with dialysis decreases with increasing age. True/False?
True
Kidney is taken out in transplant. True/False?
False
Leave kidneys and put new kidney in lower iliac fossa/pelvis
Which donor blood groups are compatible with recipient with blood group O?
O
Which donor blood groups are compatible with recipient with blood group A?
O
A
Which donor blood groups are compatible with recipient with blood group B?
O
B
Which donor blood groups are compatible with recipient with blood group AB?
O
AB
People with blood group O have which antibodies? What is the effect of this?
Anti-A and anti-B antibodies, so can only receive donor from person with blood group O
What are HLA proteins? List the main types
Cell surface proteins that activate the immune system in graft rejection
HLA A, B and DR
Which HLA are class 1?
HLA A
HLA B
Which HLA are class 2?
HLA DR
1 HLA is inherited from each parent. True/False?
True
A patient who has been exposed to non-self HLA Ag forms antibody to it and this leads to rejection. What are the main ways HLA Ag exposure can occur?
Blood transfusion
Pregnancy
Previous transplants
Outline the process of graft rejection
HLA antigen binds to dendritic cell which expresses MHCII that activates CD4 cells, which enable B cell proliferation (produce antibodies to graft) and CD8/NK production which directly attack graft
Describe the 3 forms of graft rejection
Hyperacute: preformed Ab to transplant, minutes (black kidneys)
Acute: T/B-cell mediated, early on
Chronic: immune/vascular deterioration of transplant
Acute graft rejection may be treatable with immunosuppression. List some medication
Steroids
MMF
Cyclosporin
Tacrolimus
Which class of drug includes cyclosporin and tacrolimus? How do they work?
Calcineurin inhibors
Inhibit activation of CD4 cells (thus reduce NK/CD8/B-cell proliferation)
List some side effects of calcineurin inhibitors
Renal dysfunction Hypertension Diabetes Tremors Drug interactions
How do azathioprine and mycophenolate help in immunosuppression?
Block purine synthesis - suppress proliferation of B and T cells
Can cause leucopenia, GI upset, anaemia
Which drug does azathioprine notably, infamously, dangerously interact with?
Allopurinol
List the main types of donor kidney
Brain dead patient
Cardiac dead patient
Live donor (familial)
Kidney-pancreas dual transplant (diabetics)
Allocation of kidneys in UK is based on tissue typing and then time on donor list. True/False?
True
List absolute contraindications to transplantation of kidney
Malignancy (active or within last 2-5 years) Active HCV/ HIV Untreated TB Severe IHD/ airway disease/ PVD Active vasculitis Hostile bladder
List people at risk of progression to dialysis
Inheritable renal conditions CKD/AKI CVD/ hypertension Proteinuria Diabetes Smoking Chronic NSAID use Untreated UT obstruction
What are the 3 key principles of dialysis?
DIFFUSION: movement of solutes from high to low conc.
CONVECTION: movement of water in response to pressure gradient (ultrafilitration)
ADSORPTION: plasma proteins to membrane and absorb protein-bound solutes
What is the difference between haemodialysis and haemodiafiltration?
Increased connective force, increased volume of pressure driven ultrafiltrate (SOLUTE DRAG)
How do you explain haemodialysis to a patient?
Insert fistula to act as an artifical kidney putting good things in (nutrients, vitamins) and taking waste out, involves minor procedure
How do you explain peritoneal dialysis to a patient?
Insert tube into tummy which connects to a machine overnight - puts fluid in which is left for a few hours and drained - can do it at home, giving patients more freedom
How long after transplantation does a patient get the survival benefit?
3 months
List complications of renal transplantation
Bleeding Arterial or venous stenosis Wound infection Lymphocele Ureteric stricture
State the main side effect of immunosuppression and list types
Bacterial (UTI/ URTI)
Prophylaxis for PCP
Fungal
Viral (CMV, HSV, BK)
