Renal Replacement Therapy Flashcards
Functions of the kidneys
Excretion of nitrogenous waste products Maintenance of acid and electrolyte balance Control of BP Drug metabolism and disposal Activation of vit D Production of erythropoietin
Definition of end stage renal disease
Irreversible damage to a persons kidney so severely affecting their ability to remove or adjust blood wastes that, to maintain life, he or she must have either dialysis or a kidney transplant
Until what stages of CKD may the patient be asymptomatic?
4 or 5
What is the syndrome of advanced CKD called?
Uraemia
What is the earliest cardinal symptom of uraemia?
Malaise and fatigue
What is renal replacement therapy (RRT)?
The means by which life is sustained in patients suffering from end-stage renal disease
When is RRT usually indicated?
eGFR < 10ml/min
Types of RRT
Renal transplant
Haemodialysis
Peritoneal dialysis
Conservative kidney management
Types of PD
Continuous ambulatory peritoneal dialysis (CAPD)
Intermittent peritoneal dialysis
Definition of dialysis
A process by which the solute composition of solute A, is altered by exposing solution A to a second solution B, through a semipermeable membrane
Pre-requisites for dialysis
Semipermeable membrane
Adequate blood exposure to the membrane
Dialysis access
Anticoagulation in haemodyalsis
What is the semipermeable membrane in haemodialysis?
Artificial kidney
What is the semipermeable membrane in PD?
Peritoneal membrane
How does adequate blood exposure to the membrane occur in HD?
Extracorpeal blood
How does adequate blood exposure to the membrane occur in PD?
Mesenteric circulation
What type of dialysis access is used in haemodyalsis?
Vascular
What type of dialysis access is used in PD?
Peritoneal
What must be given in haemodialysis?
Anticoagulation
Dialysis access in HD
Permanent; - AV fistula - AV prosthetic graft Temporary - tunnelled venous catheter - temporal venous catheter
What restrictions do dialysis patients have?
Fluid restriction
Dietary restriction
What is the fluid restriction of dialysis patients dictated by?
Residual urine output
What dietary restrictions are in place for haemodialysis patients?
Potassium
Sodium
Phosphate
How does PD work?
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 swell time the fluid is drained out and fresh dialysate is instilled
What does the PD fluid contain?
Dialysate contains a balanced concentration of electrolytes
In PD, what is the most common osmotic agent for ultrafiltration of fluid?
Glucose
Complications of PD
Exit site infection Tunnel infection PD peritonitis Ultrafiltration failure Encapsulating peritoneal sclerosis Tube malfunction Abdominal wall herniae
Causative organisms of PD peritonitis and their origins
Gram +ve = skin contaminant
Gram -ve = bowel origin
Mixed; suspect complicated peritonitis e.g. perforation
Indications for dialysis in ESRD
Advanced uraemia (GFR 5-10ml) Severe acidosis (bicarbonate < 10mmol/l) Treatment resistant hyperkalaemia (K>6.5mmol/l) Treatment resistant fluid overload Nephrologists judgement
What is the usual fluid restriction in HD?
500-800ml/24 hours intake
What does intake allowed =?
Urine output + insensible losses
Why is there a more liberal intake of fluid allowed in PD compared to HD?
As continuous ultrafiltration is often achieved
Complications of HD
CVS problems - intra-dialytic hypotension and cramps - arrhythmias Coagulation - clotting of vascular access - heparin related problems Allergic reactions to dialysers and tubing Catastrophic dialysis accidents (rare)
What is the most important factor in choosing modality of dialysis?
Patient choice
Where is a transplanted kidney placed?
Into the iliac fossa and anastomosed to the iliac vessels
What happens to the native kidneys?
They remain in situ
Indications for a native nephrectomy
Size (polycystic kidneys)
Infection (chronic pyelonephritis)
Why must the donor kidney be preserved?
Minimises oedema
Preserves the integrity of the tissues
Buffers free radicals
Complications of transplant
Vascular - bleeding - arterial and venous thrombosis - lymphocele Ureteric - urine leak Infections
What immunosuppressive agents can be used in kidney transplant?
Corticosteriods Calcineurin inhibitors (TACROLIMUS, CYCLOSPORIN) Anti-proliferatives - mycophenolate mofetil - azathioprine mTOR inhibitors - sirolimus Costimulatory signal blockers - belatacept Depleting agents - basiliximab - rituximab
S/Es of corticosteriods
HTN Hyperglycaemia Infections Bone loss GI bleeding
S/Es of tacrolimus
Hyperglycaemia
AKI
Tremor
S/Es of cyclosporin
Hirsutism
AKI
HTN
Gout
Immunosuppression protocols in kidney transplant
Induction = basiliximab Maintenance = tacrolimus + mycophenolate + steroids
S/Es of mycophenolate
Cytopenia
GI upset
Types of donors
Deceased donors
Living donors
Types of deceased donors
Donation after brain death (DBD)
Donation after cardiac death (DCD)
Types of living donors
Living related Living unrelated - spousal - altruistic - paired/pooled
Brain death criteria
Coma Unresponsive to stimuli Apnoea off ventilator (with oxygen) despite build up of CO2 Absence of cephalic reflexes Body temp above 34C Absence of drug intoxication
What are the cephalic reflexes?
Pupillary Oculocephalic Oculovestibular (caloric) Corneal Gag
Complications after renal transplant
Rejection CVS - CRF - HTN - Hyperlipidaemia - PT diabetes Infective Malignancy - skin - lymphoma - solid cancers
Types of acute rejection
Hyperacute rejection
Acute rejection
What is hyperacute rejection?
Pre-existing alloreactivity to donor
Pathology of acute rejection
T cell mediated rejection - tubulointerstital (Banff I) - arteritis / endothelialitis (Banff II) - arterial fibroid necrosis (Banff III) Acute antibody mediated rejection (ABMR) - ATN-like (Banff I) - capillaries and or glomerular inflammation (Banff II) - arterial inflammation (Banff III)
What does a T cell mediated rejection consist of?
Lymphocytic infiltration
Tubulitis
Endarteritis
Endotherliathisis
What does an antibody mediated rejection consist of?
Microvascular inflammation - neutrophil infiltration - glomeruli - peritubular capillaries Donor specific antibodies Positive C4d peritubular capillaries
What is the most important transplant related infection?
Cytomegalovirus
What % of transplant recipients are affected by CMV, despite prophylaxis therapy?
8%
How do transplant recipients get CMV?
Transmission from donor tissue
Reactivation of latent virus
What does CMV cause?
Pneumonitis Retinitis Gastroenteritis Colitis Nephritis
Clinical manifestation of the BK virus in renal transplantation
Ureteral stenosis
Interstitial nephritis
ESRF
Risk factors for BKAN (BK virus)
Intensity of immunosuppression Patient - older - male - white - DM - negative BKV serostatus (paediatric recipients) Graft injury HLA mismatches Ureteral stents Viral determinants - changes in epitopes of viral capsid protein VP-1
What % of patients with the BK virus loose their graft?
45-80%
Treatment of BK virus
Reduce immunosuppression
Antiviral therapy
- cidofovir +/- IVIG
- leflunomide
What type of malignancy has the highest risk of developing after renal transplantation?
Non melanoma skin
Kapsoi sarcoma
Non hodgkins lymphoma
What is the best way to treat end stage renal disease?
Kidney transplantation
How long does it take for an AV fistula to develop?
6 - 8 weeks
What is the most common and important viral infection that develops in solid organ transplant patients?
CMV
Treatment for CMV
Ganciclovir
What is the preferred mode of access for haemodialysis?
AV fistula
