By A/PROFESSOR A. VATHSALA
(Director, Kidney Transplantation, Singapore General Hospital)

The kidneys are a pair of bean shaped organs located in the back of the body on both sides of the spine. The kidneys:
• Remove waste products from the body by producing urine
• Help to regulate the salt and water content of the body
• Control blood volume and blood pressure
• Produce a hormone called Erythropoietin helps to make red blood cells in the bone marrow
• Produce an enzyme that activates Vitamin D which makes bones strong.

When both kidneys fail due to various diseases, waste products accumulate in the body and cause nausea, vomiting, coma etc. High blood pressure and leg swelling and breathlessness occur when the salt and water cannot be excreted by the diseased kidneys.

In addition, the patient becomes anaemic as not enough red blood cells are produced and the bones become weak. Finally, as many other functions of the body cannot be performed, other organs in the body fail and the patient dies without treatment.

TREATMENTS FOR KIDNEY FAILURE
There are two forms of treatment for kidney failure: kidney dialysis and kidney transplantation. Dialysis is the process by which the patient’s blood is cleansed artificially to remove waste products in patients with kidney failure. There are two types of dialysis – blood dialysis (Haemodialysis) or water dialysis (Peritoneal Dialysis).

Unfortunately, dialysis cannot remove all the waste products that accumulate in kidney failure and patients on dialysis continue to suffer many of the complications of kidney failure such as nerve weakness and infertility, to name a few. Patients on dialysis also require treatment with erythropoeitin injections and vitamin D to correct the anaemia and bone disease that occur in kidney failure.

Finally, both types of dialysis require a considerable amount of time and impose restrictions in diet, fluid intake and lifestyle for kidney failure patients. Thus while dialysis is life saving, dialysis does not cure all the problems associated with kidney failure.

Kidney transplantation is a surgical operation by which a kidney from a living or brain-dead donor is removed and then implanted into the patient with kidney failure. During the transplant operation, the surgeon makes a cut in the patient's lower abdomen above the pelvic bone; the artery and vein from the donor kidney are attached to an artery and vein in the patient’s lower abdomen, while the ureter is attached to the patient’s bladder. The patient’s diseased kidneys are left in their usual place unless they are infected or have other problems.

Once the transplanted kidney begins to function, it removes wastes from the body of the patient with kidney failure. The transplant kidney also produces the hormones produced by a normal kidney and the anaemia and bone problems are corrected. Kidney transplant patients can eat a normal but healthy diet, resume a normal lifestyle and even bear children. Thus kidney transplantation reverses nearly all of the problems in kidney failure. In order for the transplant kidney to work well and not be rejected, medicines known as “immunosuppressants” are given to transplant patients.

SOURCES OF KIDNEY TRANSPLANT
There are two sources of kidneys for transplant: live donor or cadaveric donor. In Live Donor kidney transplant, a kidney is removed from a healthy adult and transplanted immediately into the patient with kidney failure. Before an individual is considered suitable to donate a kidney, many tests are done to ensure that he/she is healthy and has normal kidney function. Live donors are generally related to the patient with kidney failure, either by blood (example: parents, brothers and sisters, uncles and aunts, cousins, nieces and nephews, offspring) or through an emotional bond (husband, wife, in-laws, close friend). If there is more than one person who wants to donate a kidney to a patient, the one who is the best match will be chosen to donate the kidney. The most important aspect about Live Donor Kidney Transplant is that it is a voluntary one. He or she can withdraw their decision at any time and their reasons are kept confidential.

After donating a kidney, live donors can return to work within four weeks and resume all their normal activities. Donors have normal kidney function after donating a kidney as the one kidney left behind takes over the job of two kidneys. Donors have no higher incidence of high blood pressure than the general population. Some donors may have some protein in the urine because they have one functioning kidney. This however does not lead to any impairment of kidney function.

As the kidney is donated by an otherwise healthy individual, patients who receive a live donor kidney transplant have few complications. On the average, patients who have undergone a live donor kidney transplant at our hospital have a life span of over 30 years. Another important advantage of a live donor kidney transplant is that such a transplant can be performed in a planned manner; in fact, it can be performed even before the patient needs to start dialysis. This is called “Pre-emptive” kidney transplantation.

In Cadaveric Donor kidney transplantation, kidneys are removed from an individual who had died after either head injury from an accident or after a stroke. In these instances, though the donor is brain dead, the organs (including, kidneys, liver, heart, lungs and corneas etc.) can be sustained in the donor for a short period of time till they are removed for the purpose of transplant. Before a cadaveric donor's kidneys can be removed for transplantation, medical tests are done to determine if they are suitable for transplantation. In addition, checks are made to ensure that they don’t carry infections or cancer. The kidneys are then transplanted into dialysis patients who have been placed on a waiting list for the transplant; usually the kidneys are transplanted into the kidney failure patient who is best matched to the donor, in terms of blood type and tissue type.

Unfortunately due to the shortage of cadaveric kidneys in Singapore, the average waiting time is seven years or more on dialysis before they can receive a kidney transplant from a cadaveric donor. Moreover, as those who have died in hospital of non-accidental causes, generally are older or have medical conditions such as high blood pressure or diabetes, cadaveric kidney transplant patients have more complications and is less successful than live donor kidney transplant patients.

Therefore, living donor kidney transplantation is the best treatment for kidney failure.