Renal: Renal Replacement Therapy Flashcards
What are the different types of renal replacement therapy?
Haemodialysis
Haemofiltration
Peritoneal Dialysis
Renal transplantation
Describe haemodialysis
Blood passed over semi-permeable membrane against dialysis fluid flowing in the opposite direction
Blood meeting a less concentrated solution = diffusion of small solutes down conc gradient
Larger filtrates do not clear as effectively
Describe Haemofiltration
Water is cleared across the dialysis membrane using positive pressure to drag small/large solutes into the waste by convection
Ultrafiltrate replaced with appropriate vol either before (pre-dilution) or after (post-dilution) the membrane
Less haemodynamic instability than HD
Outline peritoneal dialysis
Use the peritoneum as a semi-permeable membrane
Tenckhoff catheter is inserted into the peritoneal cavity and fluid is infused, solutes diffuse slowly across
Ultrafiltration can be achieved by adding osmotic agents (glucose)
Simple to perform
Can be carried out continuously at home
SE = peritonitis, exit site infection, loss of membrane function over time
Describe renal transplantation
Treatment of choice for end-stage renal failure
Types = DCD (donor after cardiac death), DBD (donor after brainstem death), LD (living donor)
Requires immunosuppression
Indications = • Kidney failure • Improves QoL • Horseshoe kidney • Polycystic kidney disease
What are the possible complications of renal replacement therapy?
Mortality ~20%
Protein-calorie malnutrition
Renal bone disease
Infection
Amyloid accumulates
Malignancy
What are the indications for RRT?
Hyperkalaemia not responding to medical treatment
Metabolic acidosis not responding to medical treatment
Uraemia
Fluid overload not responding to medical management
Oliguria/Anuria
What are the advantages versus disadvantages of different RRT options?
HD
- A = 4 days HD free a week
- D = larger filtrates so not clear as effectively, hypotension
HF
- A = enhanced removal of solutes over HD
- D = requires an extra step, anticoagulation of the blood circuit
PD
- A = simple to perform, can be done at home
- D = loss of membrane function over time
Excluding corticosteroids, name 2 immunosuppressant drugs commonly given to kidney transplant patients for maintenance therapy? What monitoring of the patient is required?
IL-2 inhibitor at time of transplant for 6 weeks - adaport
IL-2 synthesis inhibitor - tacrolimus (SE = nephrotoxic)
MMF (mycophenolate mofetil) - prevent cloning of lymphocytes against transplant, bone marrow suppression, GI symptoms (SE = diarrhoea)
Steroids - require low dose due to CVS risk
Monitoring = neurological (tremor, confusion), new onset diabetes after transplant (NODAT), gum hypertrophy, hepatitis (antimetabolites)
Why do pts with ESRD/CKS get secondary hyperparathyroidism?
2nd hydroxylation of Vit D = active form
CKD = low vit D
= low Ca absorption from the gut
Low Ca = signs to parathyroid to release PTH
What are the possible complications from a kidney transplant?
DM = due to tacrolimus + steroids (cortisol increases gluconeogensis = high glucose = insulin resistance) (need omit steroid + do morning cortisol test to see if adrenals still work - if high not addisonian)
Typical + atypical infections (tend to be in first 6 months) = CMV, pneumocystis
High risk of infection - immunosuppression
Increased risk of lymphoma - immunosuppression
• Nearly always EBV driven, either re-activation or new acquired, EBV causes DNA changes to lymphocytes - decreased immunosuppression to treat
