Renal replacement therapy 1 + 2 Flashcards
• Describe the principles involved in renal replacement therapy and
The principles of surgical and medical management of renal transplantation including selection for renal transplant, medical and surgical complications will be described
Where is the new transplant kidney placed + what are its vessels anastomosed to
Iliac fossa
Vein joined to iliac vein
Artery joined to iliac artery
Ureter joined to bladder
Are the original damaged kidneys removed in renal transplant
No, left in place unless they’re going to interfere with transplant, e.g. if they’re causing repeated UTIs or persistent hypertension despite on drugs
Indications for nephrectomy before a renal transplant (usually the original damaged kidney is just left in place)
Big size - e.g. polycystic kidney disease
If they’re causing chronic urinary infections
Post transplant complications (4)
Bleeding or clotting of the anastomosed vessels
Leaking of ureter at the anastomosed site or blockage
Increased infection risk due to the need to take immunosuppressants to immune system rejecting kidney
Acute rejection
Long term immunosuppressants post transplant increases the risk of what malignancies (2)
skin - most common
lymphoma
Renal placement therapy involves either … or …
dialysis or transplant
List some immunosuppressant subtypes (4) used post-transplant and give an example of each
Corticosteroids - prednisone
Calcineruin inhibitors - tacrolimus, ciclosporin
Anti-proliferative - mycophenolate mofetil
mTOR inhibitors - sirolimus
Side effects of long term corticosteroid use post transplant
Hypertension
Hyperglycaemia
Bone disease
Increased infection risk
General side effects of any immunosuppressant
increased infection risk
Hypertension
GI discomfort
Weight change
The immunosuppression protocol pre and post post transplant consists of 3 groups of medications, what are they
Induction agent - used either before operation or immediately after
Maintenance agents - lifelong
Rejection agents - used specifically in treatment of rejection episodes
Types of transplant donors (3)
Deceased donors
- donation after brain death
- donation after cardiac death
Living donor
Traditional form of deceased organ donor are those that died from
brain death
The number of what form of deceased donor has been on the rise due to its better long term results
donation after cardiac death
How does paired exchange organ donation work
Donor A gives to recipient B, e.g. husband can’t give to their wife but can give to someone else (recipient B)
Donor B gives to recipient A, e.g. recipient B’s sister can’t give to them but can give to recipient A (donor A’s wife)
Kidney transplant is indicated in those with… (2)
End stage kidney disease on dialysis
Advanced CKD - stages 4 or 5
Acute rejection may be suspected if blood level of what isn’t coming down
creatinine
Acute rejection is usually asymptomatic and the attack on the kidneys is either mediated by … or …
T cells (cellular mediated)
Antibody mediated
What endocrine disorder can develop as a side effect to all the immunosuppressants take post transplant
DM
Most significant infection in post kidney transplant patients is
cytomegalovirus (a common virus that remains latent and asymptomatic once infected)
Most significant infection in post kidney transplant patients is cytomegalovirus, the recipient is affected either by … or …
transmission from donor tissue
or
reactivation of latent virus within the recipient
CMV infection post kidney transplant can manifest in 2 ways (one less serious than the other)
Typical viral infection - classic symptoms of fever, myalgia, malaise, fatigue
or
Tissue invasive disease - affecting specific organs
- Principles of dialysis and its main modalities
* state the social, economic and psychological implications of dialysis and renal transplantation.
.
The syndrome of advanced CKD is called uraemia
Uraemic symptoms can involve almost every organ system but the earliest and cardinal symptoms are (2)
malaise + fatigue
RRT is indicated when eGFR
10ml/min
Modalities of dialysis
Haemodialysis
Peritoneal
How does haemodialysis work
Blood is passed through the dialyser (semi-permeable membrane) which is constantly being bathed/pumped with dialysate fluid surrounding the dialyser
High conc. toxins/small solutes in blood move out into the dialysate fluid by passive diffusion, electrolytes in dialysate fluid will move into blood to equilibrate any differences
Filtered blood then returned to body via second needle
How is haemodiafiltration different to haemodialysis
Haemodiafiltration uses CONVECTION (heat transfer due to bulk movement of molecules) rather than diffusion
Blood is passed through a high flux dialyser creating a high hydrostatic pressure which drives water and BOTH SMALL + LARGE solutes across the membrane into the dialysate fluid
However this means substitution fluid has to be infused into the blood at the same time to account for the high loss of water
A semi-permeable membrane is required for dialysis; what is the semipermeable membrane in haemodialysis and peritoneal dialysis
Artificial kidney (artificial filter) made up fine hollow fibres with pores in their walls
Peritoneal membrane
Haemodialysis requires vascular access - how may this be done (3)
Arteriovenous fistula - artery re-routed to join a vein
If vein too fragile/narrow then arteriovenous graft (synthetic tube used to join artery and vein)
If emergency, then temporary venous catheter placed into e.g. IJV in neck
Restrictions for haemodialysis patients (2) - this doesn’t apply as much to peritoneal dialysis
Fluid restriction - depends on size + weight
Dietary restriction of Na+, K+, PO4^3-
Complications of haemodialysis (4)
Hypotension
Arrythmias
Clotting of vascular access site
Allergic reaction to dialyser and tubing
How does peritoneal dialysis work
Permanent catheter inserted into abdomen
Abdomen first filled with a bag of dialysate (high glucose content) then left for a few hours (DWELL TIME) where waste products and extra fluid pass through the peritoneum from blood into the dialysate, attracted by its high sugar content
Few hours later, old fluid is drained into a waste bad and fresh dialysate is instilled to repeat process
2 types of peritoneal dialysis
Continuous Ambulatory Peritoneal Dialysis (CAPD) - manual exchange of fluid 4 times a day
Automated Peritoneal Dialysis (APD) - machine automatically performs a number of fluid exchanges while you sleep
Complications of peritoneal dialysis (2)
Exit site infection
PD peritonitis
Peritoneal dialysis relies on what process
ultrafiltration due to high glucose content of dialysate creating osmotic gradient for water to move into it from blood
Requirements for haemodialysis (4)
Semipermeable membrane
Adequate blood exposure to the membrane
Vascular access - e.g. AV fistula/graft
ANTICOAGULATION
People receiving haemodialysis may be on what medication (5)
Antihypertensives - beta blockers, CCBs, ACEI, ARBs
Diuretics
Anticoagulants - heparin
Phosphate binders - to lower blood phosphate and prevent bone disease
Erythropoietin stimulating agents/ iron supplements - to overcome anaemia
Principle of haemodialysis v peritoneal dialysis
Haemo - diffusion
PD - ultrafiltration
