Dialysis & transplantation Flashcards
What is dialysis?
Semipermeable membrane based on diffusion removes toxins from the blood
During dialysis which chemicals are being removed?
K+
Urea
Na
During dialysis what is added to the blood?
Bicarbonate
Glucose
What is the minimum treatment times for dialysis?
4 hours
3 times per week
What restrictions does dialysis put on patients?
Fluid (1L per day)
Low salt
Low potassium
Low phosphate
Pros of areteriovenous fistula
Good blood flow
Unlikely to cause infection
Cons of arteriovenous fistula
Requires surgery
6 weeks to mature
Can limit blood flow to distal arm
Can block
Pros of tunneled venous catheter
Easy to insert
Can be used immediately
Cons of tunneled venous catheter
High risk of infection
Can cause damage to veins making placing replacements difficult
Complications of tunneled venous catheter infection
Endocarditis
Discitis
Death
What is the most commonly used antibiotic for tunneled venous catheter
Vancomycin
Complications of dialysis
Fluid overload
Blood leaks
Loss of vascular access
Hypokalaemia & cardiac arrest
How does peritoneal dialysis work?
Solute removal by diffusion of solutes across the peritoneal membrane
Water removal by osmosis driven by high glucose concentration in dialysafe fluid
How many changes a day are needed for CAPD?
4 bag exchanges per day
Complications of PD
Infection
Membrane Failure
Hernia’s
Investigation for PD infection
Culture PD fluid
Treatment of membrane failure in peritoneal dialysis
Switch to haemodialysis (inabiklity to remove enough water so become fluid overload)
Why are patients on PD more prone to hernias?
Increased intraabdominal pressure
What are the bone metabolic complications of ESKD?
Phosphate retention
Low hydroxylated Vit D
Hypocalcaemia
Raised PTH
Metabolic complications in ESKD
Bone mineral metabolism
Anaemia
Sodium & water retention
Accelerated CV disease
Biochemical indications to start dialysis
Resistant hyperkalaemia
GFR 45
Unresponsive acidosis
What are HLAS?
Cell surface proteins expressed on cells
Why is HLA important?
Rejection
What causes hyperacute rejection?
Due to +ve X match
Treatment of hyperacute rejection
Remove kidney (unsalvagable)
What mediates acute rejection?
T cells or B cells
Management of acute rejection
Increased immunosupression
Examples of calcineurin inhibitors
Cyclosporin
Tacrolimus
Mechanism of action of calcineurin inhibitors
Inhibit activation of T helper cells by reducing NK clls activation and reduce cytotoxic T cell activation
Side effects of calcineurin inhibitors
Renal dysfunction
Hypertension
Diabetes
Tremors
What are azathioprine & mycophenolate?
Antimetabolites by blocking purine synthesis leads to suppression of prolieration of lymphocytes and B cells
Side effects of azathioprine & mycophenylate
Leucopaenia
Anaemia
GI side effects
Which drug does azathioprine interact with badly?
Aloopurinol
Side effects of steroids
Osteoporosis
Weight gain
Infection
Diabetes
What factors make a patient suitable for transplantation?
> 5 year life expectancy
within 6 months of HD
Tissue typing
What is assessed in a patient before transplant?
CVS risk Virology CXR Bladder assessment Co-morbidities
Absolute contraindcationf ro renal transplant
Malignancy Untreated TB Severe IHD Severe airways disease Active vasculitis Severe PVD
Surgical complications of transplant
Bleeding Aterial stenosis/thrombosis Venous stenosis/thrombosis Ureteric stricture and hydronephrosis Wound Infection
Signs of immediate graft function
Urine output good
Falling creatinine & urea
Signs of delayed graft function
Post-op acute tubular necrosis
Management of delayed graft function
Haemodialysis for 10-30 days till transplant works
What happens if a transplant fails?
Patient back on dialysis
Can get another transplant
Within what time frame is a rejection considered acute?
6 months
What is the most common cause of viral infection in solid organ transplants?
Cytomegalovirus
Treatment of cytomegalovirus
Ganciclovir
