Block 34 Week 2 Flashcards
advantages of renal transplantation?
- removes burden of life long dialysis
- improves renal clearance - dialysis only provides GFR of around 10ml/min
- improves life expectancy
+ of transplantation - renal clearance?
- improves renal clearance - dialysis only provides GFR of around 10ml/min
disadvantages of renal transplantation?
- sig perioperative mortality risk - largely cardiovascular mortality or sepsis
- 2% of perioperative mortality
- new onset post transplant diabetes (NODAT) - 10-20%
- assoc w sig inc risk of graft loss and early death
disadvantages of renal transplantation - immune related?
- lifelong burden of immunosuppression
- risk opportunistic infections - espec viral, pneumocystitis
- cancer risk - non-melanoma skin cancer, cervical, lymphoma
absolute CI for renal transplants?
- active infections
- active cancer - wait 2-5 yrs following cure
- active drug misuse
- uncontrolled major psychiatric disease that would disrupt ability to take meds
- active non-concordance w treatment
- short life expectancy - under 5 yrs
organ transplantation is governed by?
- Human Tissues Act 2004
- main change to prev legistlation - facilitated live donor transplantation between unrelated ppl
Human tissues act 2004?
- regulates activities concerning the removal, storage, use and disposal of human tissue
- consent is the fundamental principle
key points of the HTA?
- Reg storage, removal and use of human tissues
- makes it lawful to take minimum steps to preserve the organs of a deceased person for use in transplantation while steps are taken to determine the wishes of the deceased
offences under the HTA?
- removing storring or using human tissue without consent
- storing or using donated tissue for a scheduled purpose for something else
- trafficiking in human tissue for transplant purposes
types of transplants from cadaveric donors?
- heart beating - DBD
- non-heart beating - DCD
heart beating (DBD) transplant?
- heart beating (DBD) - donation after brain death. Traditionally the more common one
non heart beating donation?
- non-heart beating (DCD) - donation after cardiac death, organs no longer perfused at the time of transplantation
main diff between heart beating and non heart beating transplants?
- main difference between DBD and DCD is that in DBD the kidneys are still perfused at the time of retrieval but aren’t in DCD
- With DCD youre more likely to get delayed graft function which means that the kidneys dont intially work on implantation
changes in donation overtime?
- increase in donations from living donors over time up until 2014/2015 and then has tailed off - may be due to increased risk in end stage CKD in live donors
- DBD donors stayed the same
- DCD increased
live donors?
- related - blood or emotional relation
- unrelated
- paired or pooled donor - organs exchanged between pairs to overcome incompatibility to obtain best immunological match
- altruistic donor - person donates to anyone
how are live donations done?
- in paired or pooled transplants the organs are exchanged between donor-recepient pairs to overcome blood group or HLA incompatibility
blood groups
the independent assessor?
- All donors and organ recipients are required to see an Independent Assessor (lA) who is trained and accredited by the HTA.
- The lA interviews the donor and recipient both separately and together on our behalf and is independent of the healthcare teams who are involved with the medical parts of the process.
independent assessor interviews?
- The purpose of the interviews is to ensure that donors are not forced to do something against their wishes, to ensure that no reward has been sought or offered and to ensure that the donor has the capacity to make an informed decision.
- Donors and recipients will be asked to bring along proof of their identity and proof of their relationship.
- It is a criminal offence to carry out a transplant operation between two living people if the conditions of the HT Act are not met.
blood supply for the transplanted kidney?
- blood supply for the transplanted kidney is usually from the external iliac artery and vein usually, into the iliac fossa
- only the upper 1/3 of the ureter can be implanted when the kidney is transplanted bc its supplied by the renal artery
types of organ rejection?
- hyperacute rejection: blood group incompatbility
- acute rejection or chronic rejection MHC antigens
what is the MHC?
- genes coding for HLA, inherited
Class 1 HLA?
- Class I antigens (HLA-A, B, Cw) - expressed on all nucleated cells
Class II HLA?
- Class ll antigens (HLA-DR, DQ, DP) - expressed on antigen presenting cells, B lymphocytes and activated T cells
- can also be expressed on endothelial cells of BVs especially in the kidney
HLA and renal transplantation?
- as we have 2 copies of each HLA type, 6 different HLA antigens need to match (2 A, 2 B and 2 DR)
- If HLA types are all the same, there’s a 0,0,0 mismatch
- if 1 A, 1 B and 2 DR are the same there is a 1,1,0 mismatch
- if none of the antigens are the same theres a 2,2,2 mismatch
Triggering an immune response in transplants?
- donor antigen is presented to recepient T cells by APCs - commonly dendtitis
- the APC may be of donor origin (direct) or recipient origin (indirect)
- antigen must be presented in association w a class 2 MHC w co-stim molecules in order to initate an immune response
what are the 3 signals in the immune response?
- -> T cell activation via recognition of the antigen by the CD3 receptor - signal 1
- -> associated w costimulatory molecule CD80,86 and CD28: signal 2
- -> T cells undergo IL-2 mediated clonal proliferation
- -> CD25 is the IL2 receptor - signal 3
- -> production of cytokines to recruit more inflammatory cells
summary of the 3 signals?
- signal 1: CD3
- signal 2: CD28, CD80
- signal 3: IL2, CD25
What are costim molcules?
CD40 and CD154
what are the calcineurin inhibitors?
Cyclosporin and tacrolimus:
axathioprine?
purine synthesis inhibitor
leflunomide?
pyridimine synthesis inhibitor
anti CD52?
alemtuzumab - depletes T cells
what is hyperacute rejection?
- Hyperacute rejection occurs when the recipient has pre-formed antibodies to the donor kidney (for example with a blood group incompatible transplant) - occurs immediately
what happens during hyperacute rejection?
- Antibody binds directly to antigens on the endothelium lining the capillaries of the kidney
- Complement activation and inflammatory cell infiltration result in endothelial damage
- Platelet adhesion and vascular thrombosis lead to renal infarction
hyperacute rejection is?
immediate
what is acute rejection?
- Antigen presentation leads to T cell activation
- Activated T cells undergo clonal proliferation and infiltrate tubules -> ATI -> cell death
- ‘Helper’ T cells recruit
- Cytotoxic T cells leading to direct cellular toxicity - Predominantly tubular rejection
- B cells leading to donor specific ab production - predom vascular rejection
what are the major causes of late graft loss?
- chronic rejection
- recurrent disease
- death w a functioning graft
what is the definition of kidney failure?
- reduction in kidney function
- usually identified from: decrease in urine output, increase in serum creatinine, decrease in eGFR
AKI =
sudden decrease in kidney function over days to weeks
CKD =
- CKD: there has been a persistent decline in kidney function over a longer time
Acute on C kidney failure
means that there has beena sudden decrease in kidney function in someone with chronic kidney disease
end stage kidney disease
End stage kidney disease means that there is insufficient kidney function to maintain life without renal replacement therapy
reversibility of kidney disease
- AKI or acute on chronic kidney disease -> potential to restore kidney function to normal (acute) or baseline abnormal (acute on chronic) function
stage 1 of CKD?
normal GFR
Stage 2 of CKD?
60-89 ml/ min
Stage 3 of CKD?
3a) 45-59 ml/min
3b 30-44 ml/min
Stage 4 of CKD?
15-29ml/min
stage 5 of CKD?
<15 ml/ min or RRT
RIFLE classification of CKD
Oliguria =
- Oliguria is an abnormally low urine output
- in adults <400mls/day or <0.5ml/kg body weight/hour)
anuria =
- Anuria is no urine output
- <50mls/day
Pre-renal injury?
- this implies decreased blood flow either because of a fixed obstruction (renal artery stenosis) or far more commonly a decreased circulating volume or blood pressure
site of intra-renal injury?
- This means that the injury is within the kidney itself
site of post-renal injury?
- This means that there is an obstruction somewhere between the
renal pelvis and the urethra - obstruction has to affect both kidneys to cause renal failure
causes of pre-renal failure - true hypovolaemia?
– History of volume loss
* GI – diarrhoea and/or vomiting diarrhoea and/or vomiting
* Burns
* Haemorrhage
causes of pre renal failure - relative hypovolaemia?
– Heart failure
– Septic shock
– Hepatorenal failure
Clues for pre-renal failure?
- cause for volume depletion
- signs of hypovolaemia - tachycardia, hypotension - espec postural hypotension
clues to renovascular disease?
- Atherosclerotic vascular disease elsewhere
- Hypertension
- Vascular bruits on abdominal examination
* Deteriorating renal function with ACE-inhibition
causes of intra-renal failure - glomerular?
Glomerulonephritis
tubular causes of intrarenal failure?
- Ischaemic ATN (prolonged pre‐renal/contrast nephropathy)
- Nephrotoxic ATN (gentamicin/amphotericin/paracetamol)
- Intratubular obstruction (crystals/myoglobin/myeloma)
intersitial causes of tubular renal failure?
– Acute pyelonephritis
– Acute interstitial nephritis (drugs/infection)
vascular causes of intra-renal failure?
- Vasomotor (drugs including NSAID’s/ACE‐I’s)
- Malignant hypertension, scleroderma
- Vasculitis
- Microvascular obstruction (atheroemboli/cholesterol emboli/HUS/ TTP)
volume depletion and ACE
NSAIDs
features suggestive of intra-renal AKI?
- proteinuria - suggestive of glomerular disease
- haematuria
proteinuria - microalbuminuria?
- Microalbuminuria (measured by an albumin:creatine ratio) is an indicator of early diabetic nephropathy and capillary injury indicator of early diabetic nephropathy and capillary injury secondary to hypertension or vascular disease
- The urine dipstick test will be negative
proteinuria ?
- Proteinuria (measured by a protein:creatinine ratio) is an indicator of glomerular disease (glomerulonephritis)
- The urine dipstick test will be positive
visible haematuria?
- visible (macroscopic) - more commonly indicates bleeding within the urinary tract
invisible haematuria?
- invisible - more commonly indicates glomerular haematuria
post-renal renal failure - in order to cause renal failure?
- in order to cause renal failure, the obstruction needs to be bilateral or affect a single functioning kidney e.g. kidney transplants
sites of obstruction - PUJ?
- Bilateral pelvicoureteric junction (PUJ)
- Bilateral ureteric - tumour /retroperitoneal fibrosis / bilateral stones / bilateral sloughed papilla
Sites of obstruction - bladder outflow?
- Prostatic hypertrophy / stone / tumour / neurogenic bladder
sites of obst- urethra?
- Tumour / valves / stricture/ foreign body
clues to obstructive picture
history of:
- urinary tract surgery
- pelvic malignancy/radiotherapy - bladder symptoms
- polyuria (early obstruction)
- anuria (very late obstruction
clues to obstructive picture:
Signs of
- palpable bladder - prostatic enlargement
- abnormal rectal or vaginal examination
absence of ? makes obstruction unlikely
hydronephrosis on renal US
roles of the normal kidney
signs and symptoms of uraemia
Treatment of severe renal failure?
- dialysis
- transplantration
- conservative care of ESRF - symptom management
cautions of ACE/ ARB
- hyperkalaemia
- fall in GFR
- renal artery stenosis
- volume depletion
Tx of water/ sodium retention?
- dietary salt restriction
- loop diuretic
anemia?
- less EPO -> anaemia
- treat w recombinant EPO if sympptomatic
- target hb: 100-120
- avoid overcorrection - risk of excess cardiovascular mortality
pathophys of sodium retention?
consequences of severe hyperkalaemia?
- can cause cardiac arrest
Pathophys of bone disease
pathophys of acidosis and hyperkalaemia
Staging of CKD
- Stage 1: Normal GFR; GFR >90 mL/min/1.73 m2 with other evidence of chronic kidney damage
- Stage 2: Mild impairment; GFR 60-89 mL/min/1.73 m2 with other evidence of chronic kidney damage
- Stage 3: Moderate impairment; GFR 30-59 mL/min/1.73 m2
- Stage 3 CKD should be split into two subcategories defined by (2):
- GFR 45-59 ml/min/1.73 m2 (stage 3A)
- GFR 30-44 ml/min/1.73 m2 (stage 3B)
- Stage 4: Severe impairment: GFR 15-29 mL/min/1.73 m2
- Stage 5: Established renal failure (ERF): GFR < 15 mL/min/1.73 m2 or on dialysis