lunes, 4 de marzo de 2019

What is a kidney transplant?

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

A kidney transplant is an operation where a healthy kidney from one person (the donor) is transferred to a person who has little or no kidney function (the recipient).

Normal kidneys and their function

The kidneys are two bean-shaped organs located on each side of the body, just below the ribcage. These organs work continuously to filter waste products from the blood and convert the waste into urine.

When is a kidney transplant needed?

Loss of kidney function means these waste products can build up in the body leading to life threatening complications. Normally a kidney can function with small amount of damage. With progressive damage it may reach a point of no return called “End Stage Renal Disease” or ESRD. This is also called chronic renal failure. This is the most common condition that may require a kidney transplant.

At initial phases before a donor kidney is available the functions of the kidney are replicated by an artificial blood filtering procedure called dialysis. But dialysis can be inconvenient, expensive and time-consuming and the treatment of choice for end stage chronic kidney disease remains kidney transplant.

Types of kidney transplant

There are two kidneys in the body and a person only needs one kidney to survive. Thus, unlike other organ donations like heart and liver, living donors may donate a kidney. This ideally should be a close relative so that the blood group and tissue types match. This type of donation is known as a living donation. A similar blood and tissue type ensures that there is less risk of the body rejecting the kidney.

Kidney donations are also possible from donors who have recently died. These may not match the recipient in tissue and blood group type and face the risk of being rejected by the body. The body perceives the new kidney as foreign object and mounts an immune attack against it. This can be suppressed by using long term immunity suppressing drugs.

Kidney transplant procedure

The surgery is commonly performed under general anesthesia. The abdomen is opened and the surgeon places the new kidney inside the lower abdomen and connects the artery and vein of the new kidney to the existing renal artery and vein after removing the diseased kidney. The blood flows through the new kidney, which makes urine like the original kidney.

Risks of kidney transplant

A kidney transplant is a major surgical procedure and common risks include risk of pain, bleeding, infections and formation of blood clots. Long term risks are associated to the donor organ rejection by the recipient’s body. The immunity suppressing medications also have side effects which may be cumbersome on long term use.

Life after kidney transplant

Lifestyle after kidney transplant should be healthy with no smoking, eating a healthy diet, losing weight and exercise regularly. These measures prevent the onset of kidney disease in the donated organ as well for as long as possible in most cases.

The outlook is generally good for those who have had a living donation, or one from a close relative or someone with the same tissue type, the age and general state of health of the recipient etc.

Over 90% of transplants should be working 1 year after surgery. Around 8 out of 10 of people who receive a live donation will live for at least five years after receiving the donation.

Young people and children live much longer. The success rate (at least five year survival) of recipients of kidneys from dead donors is 7 in 10. In general, a transplant from a deceased donor has a mean survival rate of 15 years, and a living transplant about 18-20 years.