The treatment of chronic renal failure

A chronic loss of kidney function may be caused by a number of factors, these commonly include diabetes, glomerulonephritis, chronic hypertension and familial polycystic renal disease (see ‘Diabetes mellitus’ and ‘Hypertension’). A decline in renal function causes a gradual accumulation of the body's waste products and this is indicated by increasing levels of urea and creatinine in the blood. The metabolic disturbance accompanying renal failure leads to a number of physical symptoms, most notably lethargy and drowsiness, nausea and vomiting, as well as anorexia (see ‘Vomiting and nausea’).

The point at which patients are offered dialysis as a treatment for renal failure can vary according to the different policies of renal units, but treatment is typically instituted when the patient's renal symptoms reach a level that interferes with their ability to carry out their work or normal daily functions. Earlier treatment is associated with better survival and a preservation of nutrition. Some patients with a particularly poor medical prognosis, or with other major health problems that interfere with successful adaptation to a life on dialysis, may be advised against treatment.

Haemodialysis and continuous ambulatory peritoneal dialysis (CAPD) are the two types of dialysis treatment used to correct the on-going effects of kidney failure. In haemodialysis, the patient's blood is passed through an artificial kidney machine that removes waste products by passing the blood across a semi-permeable membrane. Most patients on haemodialysis must dialyse three times a week for between four and six hours.