Renal Transplant Flashcards
A transplanted kidney is placed where?
Iliac fossa and anastomosed to the iliac vessels
What happens to native kidneys during a renal transplant?
Usually remain in situ
What are the indications for native nephrectomy?
Size (polycystic kidneys)
Infection (chronic pyelonephritis)
What is the Supply-Demand deficit for kidney transplants like currently?
Take on rate for end stage renal failure is increasing
Demand for transplantation is increasing
Marginal increase in transplant rate
Ever increasing size of waiting list and length of wait to first offer
How are countries dealing with increased kidney dornor demand?
More education
-Increase people willing to donate
More ABO incompatible
-Transplants of differing blood types
More dead donors
What are the different organ sources that can increase our donor pool?
Cadaver “brain dead” donors
-Standard/ extended criteria
Non heart beating donors
-Donation after cardiac death
Living Related donor
Living Unrelated donors
- Spousal
- Altruistic
- Paired/pooled
What are the brain death criteria?
Coma, unresponsive to stimuli
Apnoea off ventilator (with oxygenation) despite build up of CO2
Absence of cephalic reflexes
Body temperature above 34 degrees celcius
Absebce of drug intoxication
- Ethanol
- Anaesthetic drugs
- Paralysing drugs
What do we mean by abcence of cephalic (brainstem) reflexes in brain death criteria?
- Pupillary
- Oculovestibular
- Oculocephalic
- Corneal
- Gag
- Purely spinal reflexes may be present
How are deceased donor kidneys selected?
Standard criteria (DBD)
Extended criteria (ECD)
- Donor aged >60 years
- Donor aged >50 years with history of hypertension
- Stroke as a cause of death
Donation after cardiac death (DCD)
What are the different systems for living kidney donation?
Live related donor
Live unrelated donor (e.g. spousal)
Live unrelated donor - altruistic, non- directed
Paired/ pooled
ABO incompatible/ HLA incompatible
What are the positives and negatives of live unrelated kidney donation?
Negatives:
- Usually poorly matched
- Heavier immunosuppression
- Higher rate of sensitisation if it fails
Positives:
- High degree of donor/ recipient satisfaction
- Same survival as living related, better than cadaveric
What is paired donation?
Imagine 2 recipients.
Recipient 1 has a wife willing to donate but they have a cross-match incompatibility
Recipient 2 has a brother willing to donate but they have a blood type incompatibility.
With paired donation wife or recipient 1 can donate to recipient 2 and brother of recipient 2 can donate to recipient 1
Allowa sensitive individuals to find the correct pair and undergo transplant.
What is pooled donation?
Same principle as paired donation but more people involved -> potentially better match
Some dont want to enter a pool donation
What is the relative risk of death post op?
Is surgery worth it?
Higher risk of death around time of surgery
As this goes on -> around maybe 4 months the survival risk will decrease below relative risk
Transplant isnt without risk but long term seems to be worth it
What is the survival rate for kidney donors compared to the general population?
Vertually just as high as controls from the general population
Donation isnt associates with decreased survival as long as donors aren’t inactive, bad diet etc
What complications can occur after a renal transplant?
REJECTION
Cardiovascular
Infective
Malignancy
What rejection complecations can occur after renal transplantation?
Cell mediated
Humoral (Ab mediated)
What cardiovascular complications may occur after renal transplantation?
Underlying renal disease Chronic Renal Failure Hypertension Hyperlipidaemia PT diabetes
What malignancy complications may occur after renal transplantation?
Skin
Lymphoma
Solid cancers
Why does hyperacute rejection occur?
Pre-existing alloreactivity to donor
What are the two types of acute rejection?
Acute T cell mediated rejection
-Acute cellular rejection
Acute antibody mediated rejection
-Acute humoral rejection, C4D+
What does Type I acute rejection involve?
Lymphocytic infiltrate
Tubulitis
What does Type II acute rejection involve?
Endarteritis
Endothelialitis
What does humoral rejection involve?
Neutrophil infiltration
- Glomeruli
- Peritubular capillaries
- > Endothelial swelling
Positive C4D
-peritubular capillaries
How does rejection come about?
Rediculously basic version
Antigen-presenting cells of host or donor origin migrate to T-cell areas of secondary lymphoid organs. These T cells ordinarily circulate between lymphoid tissues.
4 APCs present donor antigen to naive and central memory T cells. Antigen triggers T-cell receptors and synapse formation.
Describe immunosuppression agents and their action briefly
Non-specific
- Prednisolone
- Azathioprine
T-cell activation specific
- Cyclosporin
- Tacrolimus
mTOR inhibitors
-Rapamycin (sirolimus)
Anti-IL2 receptor antibodies
T cell antibodies
- ATG
- OKT3
What infection do you need to keep an eye out for in transplant patients?
CMV
Most common opportunistic infection after transplantation
High mortality if untreated
What are the primary effects of CMV infection?
- CMV syndrome
- Gastroenteritis
- Nephritis
- Hepatitis
- Pneumonitis
- Retinitis
how do you avoid CMV in renal transplant patients?
Prophylaxis for CMV shows increased survival
Usually given for 6 months
What problem can Human polyomaviruses cause?
Human polyomaviruses infect many types of cells, including kidney, brain, liver, retinal, lung, blood, lymphoid, heart, muscle, and vascular endothelial cells.
Viral particles bind a specific cell-surface receptor on a permissive cell type and produce T antigens early in the infection cycle. These antigens bind intracellular proteins to promote viral replication and block tumor-suppressor proteins (p53 and p105).
What viruses are included in polyomaviruses?
BK virus
JC virus
Murine polyoma virus
SV40
Why do we need to look out for BK virus?
BK virus (BKV) causes nephropathy in renal-transplant recipients and hemorrhagic cystitis in patients with AIDS and those who have undergone bone marrow transplantation
What is JC virus associated with
JC virus (JCV) is associated with progressive multifocal leukoencephalopathy (PML), primarily in patients with AIDS
How do you treat BK virus infection?
Antiviral therapy
- Cidofovir (+/- probenicid)
- Leflunomide
Modification of immunosuppression
