L3 - Kidney Failure

• The presence of blood cells or protein the the urine indicates kidney disease
• To test for protein use a biuret reagent
• If protein is present biuret reagent changes colour from blue to lilac
• Kidney failure can be treated by dialysis or kidney transplant
• A diseased kidney may be replaced by a healthy one by transplant from a donor of a similar 'tissue type' to the recipient. Usually a family member.
• The donor kidney may be rejected by the body, attacked by the immune system, unless immunosuppressant drugs are taken which suppress the immune response.
• Dialysis involves filtering and cleaning the blood
• A dialysis machine uses counter current flow
• Diffusion of urea, excess salts and water occurs across the whole of the machine because it maintains a concentration gradient
• The dialysis fluid contains the same concentration of glucose and amino acid as the blood to ensure that diffusion of these useful substances does not occur
• Kidney transplant:

  • Tissue typing required
  • Risk of rejection
  • Immunosuppressant drugs must be taken
  • Donor kidneys only last around 8 years
  • Can be hard to find donors
  • Can lead a normal life after the operation
• Dialysis:

  • Limited diet of protein and salt
  • Regular dialysis sessions impact on the patient's lifestyle
  • Available straight away
  • Expensive for the NHS
  • No immunosuppressant drugs need to be taken