Kidneys: Dialysis and Transplantation Flashcards
How would you use Renal Replacement Therapy
- what is the gold standard
- what are the other forms
When would you use RRT
Ideally a living donor, can be deceased
Haemodialysis
- requires AV fistula formation
- can be done in home or hospital
Peritoneal dialysis (CCP/CAPD)
- allows independence
- not ideal for 5+ years
Preemptive transplantation
- uremic symptoms (fatigue, poor appetite, nausea)
- difficulty in controlling K, acidic pH, fluid volume
Indications for dialysis
Stage 4 => considered
Stage 5 => started as kidneys not compatible with life
Acidosis - refractory
Electrolyte imbalances - refractory hyperkalemia K
Ingestion of toxins
Overload - pulmonary edema resistant to diuretics
Uremia - pericarditis, encephalitis
What does dialysis do
Remove waste products, extra fluid => reverse uremia, hypervolemia
Maintain electrolyte, pH balance => address hyperkalemia, acidosis
No changes in hormones, must be managed separately
- EPO
- Vitamin D
Describe hemodialysis
- types of entry point
- pros and cons
Hemodialysis (attends for 3 4hour sessions per week)
- hospital, satellite unit, home
- heparinised system
- countercurrent dialysis and filtration
- air trap prevents air embolism
AV fistula - RC/BC/BB
- 1-2month maturation
- flow rate can vary with elasticity of vessel
- risk of blows, stenoses, thromboses
Graft - plastic tube connects artery and vein (DM affects vessels)
- no maturation
- risk of blows, stenoses, thromboses, infection
Central line - IJV
- plastic tube limits flow rate
- high infection risk
Describe peritoneal dialysis
- how is it done
- pros and cons
Peritoneal (continuous ambulatory, automated)
- home based, better QOL
- needs residual kidney function, ability to lift dialysate bags
- compliance hard to monitor
Set up
-catheter inserted into abdo (lateral right to umbilicus)
1. dialysate => peritoneum from a height
2. dialysis occurs within peritoneal cavity
3. waste drained into bag at lower height when saturated
CAPD
-machine free, set up dialysis fluid yourself
-can do ADLs
-3-4x a day, 30mins each
APD
-machine does this for you
-normally done in the night
However not everyone is suited for peritoneal dialysis
-morbidly obese
-multiple abdo surgeries
Complications of
- hemodialysis
- peritoneal dialysis
Hypotension, anuria => loss of too much fluid
Regular access to blood compartments => sepsis
Heparinised system => bleeds
Stenoses => clots
Dialyser reaction => inflammation
Air pumped into circuit => air embolus
Peritonitis => scars membrane
Leaks => pleural effusion, hydrocele
Membrane may not be suitable for complete toxin clearance
Pros and cons of transplant vs dialysis
Transplant - Gold standard
:) QOL
:( immunosuppresants for life
:( infection, malignancy risk
Dialysis
:) no shortages
:) no need for immunosuppresants
:( limit salt and protein
:( time consuming, exhausting
ABO compatibility
ABO Ag on donor
Recipient must not have ABO AB
O => universal donors
AB => universal recipients
HLA compatibility
HLA C6
-order of important DR, B, A
- Determine HLA type of patient and donor
- ideally, you want all 6 AG pairs to match (zero mismatch) - Patient HLA AB testing
May be found due to
-blood product use
-pregnancy
-past transplant use
If HLA AB found => find a donor without the complementary AG
The significance of cold ischemia time
Ischemia triggers innate immune system => increased rejection risk
Immunosuppresion
- induction
- maintenance
Induction - risk of rejection highest in 1st 3 months
-basiliximab
-methylpred
Given around time of operation
Maintenance TRIPLE THERAPY - calcineurin inh + antiproliferative + CS
-Aim to balance SE against rejection due to SE
Calcineurin inh
-ciclosporin
-tacrolimus
Antiproliferative agents for B and T cells
-MMF
Inhibitor of DNA, RNA synthesis
-azathiopurine
Steroid - reduce cytokine and inhibit Tcell activation
Complications post transplant
Hyperacute - mins
-recipient AB against donor kidney
-rarely seen due to AB cross-reactivity testing
-REMOVE TRANSPLANT KIDNEY
Acute - within 3 months
Cell mediated rejection - treated with CS
AB mediated rejection - presence of graft dysfunction, histological tissue injury, presence of donor-specific AB, positive staining for C4d
Chronic - 3 months+
Gradual decrease in kidney function
-HTN, proteinuria
Complications of immunosuppresion
Cardiovascular complications
-underlying disease/immunosuppresion => HTN, hyperlipidemia
Malignancy
-increased risk of SCC skin
Long term steroid use
-high glucose, HTN
-thin skin
-obesity
-confusion
-peptic ulcers
-poor wound healing
Opportunistic infections
-CMV, BK
-fewer symptoms
-REFER TO TRANSPLANT UNIT IF FEBRILE
-PROMPT TREATMENT NEEDED, PATIENTS CAN DETERIORATE QUICKLY
Donor and recipient workup and investigations
Donor workup
-screen for transmissible diseases
-renal function
-crossmatch ABO, HLA type
Recipient workup
-crossmatch ABO, HLA type
-virology (HepB, C, CMV)
-urinalysis, culture
-cardiovascular assessment - high mortality from CVD
-psychology input - ensure that you will be ready to manage life with a transplant
Renal transplantation
-indications
-prognosis
-what it would involve after surgery
ESKF to improve QoL and long term survival
-diabetic nephropathy
-HTN
-glomerulopnephritis
-PKD
-chronic pyelonephritis
Lifelong risk of rejection - lifelong immunosuppression
Increased risk of infection, malignancy
Survival rate is very good
-10 year survival for 1st grafts 70-80%
Live related recipients are more successful than cadaveric transplants
Reduced or eliminated needs for dialysis
