Lecture 20: Renal Replacement Therapy Flashcards
list the functions of the kidneys
- excretion of nitrogenous waste products
- maintenance of acid and electrolyte balance
- control of blood pressure
- drug metabolism and disposal
- activation of vitamin D
- production of erythropoietin
clinical features of advanced CKD
- until CDK stage 4 or 5 the patient may be asymptomatic.
- the syndrome of advanced CDK is called uraemia.
- uraemic symptoms can involve almost every organ
what eGFR value is renal replacement therapy indicated?
usually indicated when eGFR < 10ml/min
list the types of renal replacement therapy
- renal transplant
- haemodialysis: home or satellite/hospital
- peritoneal dialysis: continuous ambulatory peritoneal dialysis (CAPD) or intermittent peritoneal dialysis (IPD)
- conservative kidney management
what is dialysis?
Dialysis is a process whereby the solute composition of a solution, A, is altered by exposing solution A to a second solution, B, through a semipermeable membrane (artificial kidney in haemodialysis or peritoneal membrane).
pre-requisites for dialysis
- semipermeable membrane (artificial kidney in haemodialysis or peritoneal membrane)
- adequate blood exposure to the membrane (extracorporeal blood in haemodialysis, mesenteric circulation in PD)
- dialysis access: vascular in haemodialysis, peritoneal in PD
- anticoagulation in haemodialysis
list permanent and temporary haemodialysis access types
permanent:
- arteriovenous fistula
- AV prosthetic graft
temporary:
- tunnelled venous catheter
- temporary venous catheter
list the restrictions for dialysis patients
fluid restriction:
- dictated by residual urine output
- interdialytic weight gain
dietary restriction:
- sodium
- potassium
- phosphate
describe peritoneal dialysis
- a balanced dialysis solution is instilled into the peritoneal cavity via a tunnelled, cuffed catheter, using the peritoneal mesothelium as a dialysis membrane.
- after a dwell time the fluid is drained out and fresh dialysate is instilled.
what is the most common osmotic agent for ultrafiltration of fluid in peritoneal dialysis?
glucose
what are the complications of peritoneal dialysis?
- exit site infection
- ultrafiltration failure
- encapsulating peritoneal sclerosis
PD peritonitis:
- gram positive - skin contaminant
- gram negative - bowel origin
- mixed - suspect complicated peritonitis e.g. perforation
what are the indications for dialysis in end-stage renal disease?
- advanced uraemia, (GFR 5-10ml/min)
- severe acidosis (bicarbonate < 10mmol/l)
- treatment resistant hyperkalaemia (K > 6.5mmol/l)
- treatment resistant fluid overload
discuss the fluid balance in haemodialysis and peritoneal dialysis patients
i.e. how much fluid can they consume
Haemodialysis:
- usually restricted to 500-800 ml/24hrs
- intake allowed = urine output + insensible loss
Peritoneal:
- usually more liberal intake as continuous ultrafiltration is often achieved
list some dialysis related drugs
Anaemia:
- erythropoietin injections
- IV iron supplements
Renal bone disease:
- activated vitamin D (e.g. calcitriol)
- phosphate binders with meals (CaCO3)
- heparin to prevent blood clotting
- water soluble vitamins
- ?antihypertensives
list the complications of haemodialysis
CV problems:
- intra-dialytic hypotension and cramps
- arrhythmias
Coagulation:
- clotting of vascular access
- heparin related problems
Other:
- allergic reactions to dialysers and tubing
- catastrophic dialysis accidents (rare)
list the complications of peritoneal dialysis
Infection:
- exit site infection
- tunnel infection
- peritonitis
Mechanical:
- tube malfunction
- abdominal wall hernia
Ultrafiltration problems
what does conservative kidney management involve?
Supportive care:
- priority for symptomatic management
- holistic multi-professional approach
- anticipatory care planning
do patients on dialysis have increased or decreased morbidity and mortality?
increased
describe the process of renal transplantation
- transplanted kidney is placed into the iliac fossa and anastomosed to the iliac vessels
- native kidneys usually remain in situ
what are the indications for removing native kidney/s when performing renal transplantation?
- size (polycystic kidneys)
- infection (chronic pyelonephritis)
what are the surgical complications of a renal transplant?
vascular complications:
- bleeding: usually anastomotic sites, perirenal haematoma can be arterial or venous
- arterial thrombosis
- venous thrombosis
- lymphocele
Ureteric:
- urine leak
- Infections
what are the side-effects of corticosteroids?
used for immunosuppression after kidney transplant
- hypertension
- hyperglycaemia
- infections
- bone loss
- GI bleeding
what are the side effects of Tacrolimus?
Calcineurin inhibitor used for immunosuppression after kidney transplant
- hyperglycaemia
- AKI
- tremor
what are the side-effects of cyclosporin?
Calcineurin inhibitor used for immunosuppression after kidney transplant
- hirsutism
- hypertension
- AKI
- gout
what are the side effects of mycophenolate mofetil?
anti-proliferative used for immunosuppression after kidney transplant
cytopenia
GI upset
what are the side effects of Sirolimus?
mTOR inhibitor used for immunosuppression after kidney transplant
- lipidogenic
- diabetogenic
- pneumonia
what are the side effects of Belatacept?
Costimulatory signal blocker used for immunosuppression after transplant
- infections
- malignancy
what are the side effects of anti-thymocyte globulin (ATG)?
depleting agent used for immunosuppression after kidney transplant
infections
PLTD
describe a common immunosuppression protocol after kidney transplant
- induction: Basiliximab
- maintenance: Tacrolimus + Mycophenolate + steroids
- steroid free is possible
- others: CNI-free using Belatacept
complications after renal transplantation
Rejection:
- cell-mediated
- humoral (Ab mediated)
Infective:
- bacterial
- viral
- fungal
CV:
- underlying renal disease
- CRF
- hypertension
- hyperlipidaemia
- PT diabetes
Malignancy:
- skin
- lymphoma
- solid cancers
describe hyperacute transplant rejection
Hyperacute rejection (within minutes):
- caused by ABO/HLA incompatibility
- presents with graft thrombosis/systemic inflammatory response syndrome (SIRS) within minutes of the transplant and intra-operatively.
- this is managed by immediate graft removal. This can be prevented by pre-treatment ABO and HLA cross-matching.
discuss acute transplant rejection
Acute rejection (within first 6 months):
- may be T-cell mediated and/or antibody mediated.
- Presents with an acute decline in graft. function, and there may also be fever, malaise and graft tenderness
what is the most important transplant-related infection?
Cytomegalovirus:
- affects around 8% of transplant recipients, despite prophylaxis therapy
- high mortality and morbidity if untreated
- recipient affected via: transmission from donor tissue, reactivation of latent virus
cytolomegalovirus viremia, is a tissue invasive disease causing…
the ‘itis’
- pneumonitis
- hepatitis
- retinitis
- gastroenteritis
- colitis
- nephritis
- fever
- deranged LFTs
BK virus can occur as a complication of kidney transplantation, what are its clinical manifestations?
a polyomavirus
- ureteral stenosis
- interstitial nephritis
- ESRF
what are the risk factors for BK virus associated nephropathy (BKAN)?
- intensity of immunosuppression: tacrolimus, mycophenolate mofetil, antithymyocyte globulin
- patient determinants: older age, male gender, white ethnicity, DM, negative BKV serostatus (paediatric)
- organ determinants: graft injury, HLA mismatches, ureteral stents
- viral determinants: changes in epitopes of viral capsid protein protein VP-1
what is the outcome of BKAN?
- allograft dysfunction
- loss of graft in 45-80%
what is the treatment for BKAN?
- reduce immunosuppression
- antiviral therapy: cidofovir +/- IVIG
- leflunomide
