Dialysis is a treatment for patients with end-stage renal failure (ESRF) whereby toxins and excess fluid are removed from the body by filtration devices either in the form of peritoneal or haemodialysis.
These can be broken down into:
Signs of current renal replacement such as:
- AV fistula – always comment on whether this is functioning
- Tunnelled central venous line
- Peritoneal dialysis catheter
Signs of previous renal replacement such as:
- Scars on thorax indicating previous tunnelled lines
- Abdominal scars which may represent previous peritoneal catheter sites
- Non-functioning AV fistulae
Look for evidence of complications of ESRF or dialysis such as:
- Abdominal scars – laparotomy scar may signify previous peritonitis associated with peritoneal dialysis
- Parathyroidectomy scar – for secondary/tertiary hyperparathyroidism
- Pallor indicating anaemia
Look for clues as to the aetiology of ESRF such as:
- Fingerprick marks on the hands from diabetes CBG testing
- Other features of diabetes such as necrobiosis lipoidica diabeticorum
- Lipodystophy associated with membranoproliferative glomerulonephritis
- Enlarged liver/spleen may suggest polycystic kidney disease
Lastly, comment on the adequacy of current mode of renal replacement
- Signs of uraemia
Symptoms of ESRF include:
Reduced urine output
Oedema – may be perceived as weight gain
- Autosomal Dominant Polycystic Kidney Disease
Investigations for patients with AKI/CKD of unknown cause:
Urine dipstick– blood/protein
PSA if male with possible obstructive uropathy
Blood cultures if pyrexial
CXR ?Infection ?pulmonary haemorrhage
Renal USS – ?obstruction, ?size of kidneys, ?renal cysts
Renal biopsy if cause remains unclear
Management of CKD/ESRF:
Treatment is focused on:
Treatment to address any underlying or reversible causes e.g. diabetes, hypertension or glomerulonephritis
Treatment to prevent progression – BP control with ACEi/ARB
Treatment of complications – renal osteodystrophy (osteomalacia/osteoporosis), anaemia, secondary or tertiary hyperparathyroidism
Treatment to reduce proteinuria – ACEi
Early dialysis and transplant planning – patients are often seen in a ‘predialysis clinic; where these treatments can be planned early with appropriate support and counselling from specialist physicians, dialysis nurses, dieticians and renal psychologists if necessary.
To gain most marks in the renal replacement therapy station try to work out why they have developed ESRF. To complete the examination state that you would want to perform fundoscopy to assess for either diabetic or hypertensive retinopathy.
It is important to be aware of the different modes of dialysis and potential complications associated with both. The following questions frequently come up in the renal replacement therapy station.
What is the difference between haemodialysis and peritoneal dialysis?
Haemodialysis takes place using either an AV fistula or tunnelled venous line which is usually a temporary measure whilst waiting for an AV fistula to mature. Dialysis can also take place via a femoral line and these are usually inserted as an emergency measure for patients requiring urgent haemodialysis. Once patients are established on haemodialysis they usually dialyse 3 times a week and sessions generally last 4 hours.
Peritoneal dialysis takes place through a peritoneal catheter which is a permanent catheter leading into the abdominal cavity. Fluid is infused into the catheter and into the abdomen. Toxins then diffuse across the peritoneum and into the dialysate fluid. This is then removed either whilst the patient sleeps (known as automatic peritoneal dialysis) or at various points up to 6 times throughout the day (known as continuous ambulatory peritoneal dialysis).
Why might a patient have a tunnelled venous line for dialysis rather than AV fistula?
Tunnelled venous lines are generally used as a temporary means of haemodialysis whilst waiting for an AV fistula to mature, or can sometimes be created if emergency access for haemodialysis is needed. They are not ideal for long term haemodialysis as they are more prone to infection, have a short lifespan and have lower blood flow rates which means that dialysis sessions take longer.
What are the potential complications of dialysis?
Dialysis washout – removal of too much fluid can cause hypotension, chest pain, headache and nausea
Infection – especially the tunnelled venous catheters,
Bleeding – heparin is used as an anticoagulant during dialysis and can lead to bleeding
Amyloidosis – accumulation of b2-microglobulin
Infection – peritonitis
Local complications – hernias, catheter site infections
Written by Jo Corrado
Resources used to write this document are listed in the references section of this webpage