Function of Kidneys:
The kidneys are a pair of bean shaped organs, whose essential function is to remove excess fluids, minerals and waste products from the blood and regulate fluid levels. When kidneys become non-functional, harmful excretory products accumulate in the blood and the body may retain excess fluid, which could become life threatening.
Kidney Disease and Indication for Transplant:
Kidney diseases may be categorized into acute kidney disease and chronic kidney disease.
Acute kidney disease (AKD): is a temporary, reversible kidney disease, which can be corrected through medications and hydration. However kidney function may take several weeks to return to normal.
Chronic kidney disease (CKD): refers to a permanent, irreversible loss of kidney function. The last stage (Stage-5) of CKD is known as end stage renal disease (ESRD). Renal transplantation has become the treatment of choice for patients suffering from chronic irreversible kidney disease, which has failed to respond to other medications or surgical treatments.
Non-Functional Kidneys can be Treated by one of the Following Three Procedures:
- Peritoneal Dialysis
- Kidney Transplant
What is Kidney Transplantation?
Kidney transplantation, also known as renal transplantation, is a surgical procedure that involves transplanting (implanting) a healthy kidney into a patient with ESRD.
Classifying Kidney Transplantation:
Kidney transplantation has been classified into two categories based on the source of the donor organ.
Cadaveric Donor: In this case the kidney of a deceased person is used in transplantation. Cadaveric donors can be further categorized into two groups:
- Brain dead donors (BD)
- Donation after cardiac death donors (DCD)
Living Donor: In this case the kidney of a living person is used in transplantation. Living donors may be the classified into:
- Living blood related: Siblings, parents, aunts, uncles, children over the age of 18, cousins or grandparents, etc.
- Emotionally related: Friends, relatives, spouses, in-laws, etc.
- Altruistic Donors: Anonymous donors who voluntarily donate a kidney as an act of philanthropy.
Amongst these types of kidney donors, living blood related donors are regarded the best option as they have a greater chance of matching due to genetic factors.
Matching and Compatibility:
Three tests are conducted to evaluate the eligibility of a suitable kidney donor for transplantation.
Blood and Tissue Types: For kidney transplantation to take place, the donor blood type must be compatible with the recipient. The four blood types are A, B, AB or O. The same rules apply for transplantation as they do for blood transfusion. Blood type O is considered the universal donor; they can give blood or an organ to a person with any blood type and AB is regarded as the universal recipient; they can receive an organ or blood from a person with any blood type.
HLA Typing / Tissue Typing: HLA or human leukocyte antigens are proteins found on the cells in the human body. Of the 100 different antigens which have been identified, six antigens are very important in organ transplantation. Of these six antigens, we inherit three from each parent. Since the HLA type is inherited, related living donors have the maximum likelihood of being compatible.
Cross Match Test: This is an important test where blood from the donor and the recipient are mixed. If a reaction occurs between the recipient’s blood and the donor's blood, the cross match is considered positive, indicating that the recipient has generated antibodies “against” the donor’s blood cells. If no such reaction occurs the cross match is classified as negative and the pair are considered compatible.
The Transplantation Process:
A kidney transplant is done under general anaesthesia. A long incision (cut) is made in the recipient's abdomen and the donor kidney is implanted in the lower right or left side of their abdomen. The vein and artery of the donor kidney are surgically connected to the renal artery and vein of the recipient and the ureter is attached to the bladder.
The non-functional kidney will not be removed unless it's causing complications. In such a case, the kidney can be removed during transplantation.
Advantages of Transplantation:
- Improves quality of life
- Fewer dietary restrictions
- Freedom from regular dialysis
Risks and Complications of Transplant: Kidney transplantation is associated with certain risks and complications.
Practical Complications: Complications that tend to occur immediately after surgery are:
- Blood clots in the blood vessels to the kidney
- Blockage of the urinary drainage from the kidney to the bladder
- Urine leak
Risk of Rejection: Rejection happens when the body recognises the transplanted kidney as a foreign object and attempts to attack it. To prevent rejection the patient is kept on immunosuppressant medications, which help to suppress the immune system and decrease the chances of rejection.
Infection: Immunosuppressant medications suppress the defence system so as to prevent organ rejection, however they also decrease the body’s ability to fight disease, thereby increasing the patient's risk of infection. The risk of infection is at its maximum during the early period post-transplantation, when dosages of immunosuppressant medications are at their highest. Thus it becomes important to protect the patient from exposure to infection.
Malignancy: Kidney transplant patients have a higher risk of getting cancer; skin cancer being the most common type.
Donor Risk Factors: Although donor organs are screened for various diseases prior to transplantation, transplant recipients may be at risk of contracting certain diseases from the organ donor, such as infectious diseases and cancers that were not detected during the screening process.