Renal Transplant Flashcards
Most common technical (surgical) complication of renal transplants
related to the ureteric anastomosis.
Graft survival is directly related to what “time”?
“warm ischaemic time”
=> Long warm ischaemic times increase the risk of acute tubular necrosis
Name the 3 types of organ rejection which can occur following renal transplant
Hyperacute
- immediate
- pre-formed antibody (e.g. ABO incompatibility)
Acute
- in first 6 months
- T cell mediated
- causes tissue infiltrates and vascular lesions
Chronic
- after the first 6 months
- Vascular changes predominate
Risk factors for hyperacute rejection of renal transplant
- major HLA mismatch
- ABO incompatibility.
Describe the appearnce of a hyperacute rejection after completion of the vascular anastomosis and removal of clamps.
- kidney becomes mottled/dusky
- vessels will thrombose
Treatment of hyperacute rejection
- removal of the graft
If you leave the renal transplant in situ following a hyperacute rejection, what will occur?
abscess formation
What increases the risk of a chronic organ rejection
- Previous acute rejections
- other immunosensitising events
What is the most common cause of a chronic graft rejection? How does this occur?
Vascular changes
=> myointimal proliferation leading to organ ischaemia
What technical complication is described below?
Sudden complete loss of urine output
renal artery thrombosis
What technical complication is described below?
Uncontrolled hypertension, allograft dysfunction and oedema
Renal artery stenosis
What technical complication is described below?
Pain and swelling over the graft site, haematuria and oliguria
renal vein thrombosis
What technical complication is described below?
Diminished urine output, rising creatinine, fever and abdominal pain
urine leaks
What technical complication is described below?
Common complication (occurs in 15%), may present as a mass, if large may compress ureter
lymphocele
Management of transplant associated renal artery thrombosis
Immediate surgery may salvage the graft
delays >30 mins = high rate of graft loss
Management of transplant associated renal artery stenosis
Angioplasty
Management of transplant associated renal vein thrombosis
Management options poor, graft often lost
Findings on investigation of suspected urine leak following renal transplant
US-perigraft collection
necrosis of ureter tip
Management of urine leak in renal transplant
anastomosis revision
Management of a lymphocele following renal transplant
percutaneous drainage and sclerotherapy
OR intraperitoneal drainage
What is HLA?
human leucocyte antigen (HLA) system is the name given to the major histocompatibility complex (MHC) in humans.
Which chromosome codes for HLA?
Chromosome 6.
give examples of class 1 and class 2 HLA antigens
class 1 antigens: A, B and C. Class 2 antigens: DP,DQ and DR
Importance of Class 1 vs class 2 HLA antigens in renal tranplsant
DR>B>A
Rate of graft survival in renal transplants
Cadaveric transplants:
1 year = 90%, 10 years = 60%
Living-donor transplants:
1 year = 95%, 10 years = 70%
Post-op problems following renal transplant
ATN of graft
vascular thrombosis
urine leakage
UTI
What type of graft rejection occurs in mins-hours?
Hyperacute
Cause of hyperacute graft rejection
- pre-existing antibodies against ABO or HLA antigens
(Type II hypersensitivity)
=> widespread thrombosis of graft vessels → ischaemia and necrosis of the transplanted organ
how is a hyperacute graft rejection managed?
no treatment is possible and the graft must be removed
For how long after transplant is still considered an acute graft rejection?
6 months
What causes an acute graft rejection?
- mismatched HLA
- Cell-mediated (cytotoxic T cells)
- other causes e.g. CMV
how can an acute graft rejection be identified?
- picked up by a rising creatinine, pyuria and proteinuria
how is acute graft rejection treated?
may be reversible with steroids and immunosuppressants
What is considered chronic graft rejection?
> 6 months post transplant
Cause of chronic graft rejection
- antibody and cell-mediated
fibrosis - OR recurrence of original renal disease e.g. MCGN > IgA > FSGS
What original renal disease is most likely to represent as chronic graft rejection?
MCGN > IgA > FSGS
give an example of a usual intial and maintenance immunosuppression regime following transplant
Initial:
- Ciclosporin/tacrolimus + MAB
Maintenance:
- ciclosporin/tacrolimus with Mycophenolate Mofetil or sirolimus
Calcineurin inhibitor,
(Calcineurin is a phosphotase involved in T cell activation)
Ciclosporin
Tacrolimus has a lower incidence of acute rejection compared to ciclosporin
TRUE/FALSE
TRUE
Tacrolimus causes less hypertension and hyperlipidaemia than ciclosporin. TRUE/FALSE?
TRUE
Tacrolimus has a higher incidence of what side effects compared to ciclosporin?
impaired glucose tolerance and diabetes
Which immunosuppressant blocks purine synthesis by inhibition of IMPDH?
=> inhibits proliferation of B and T cells
Mycophenolate mofetil
Common side effects of mycophenolate mofetil?
GI and marrow suppression
Which immunosuppressant blocks T cell proliferation by blocking the IL-2 receptor?
Sirolimus (rapamycin)
Side effect of sirolimus
hyperlipidaemia
Which monoclonal antibodies (IL2 inhibitors) are used in renal transplant immunosuppression?
daclizumab
basilximab
What should be monitored when patients are on long term immunosuppression following a renal transplant?
Cardiovascular disease - (due to s/e of hyperlipidaemia and hyperglycaemia)
Renal failure - look for graft faillure
Malignancy - risk of squamous cell carcinomas and basal cell carcinomas when on immunosuppression
