Renal support is the comprehensive medical care provided when the kidneys lose a significant amount of their function, a condition often termed End-Stage Renal Disease (ESRD). Kidneys perform several life-sustaining jobs, including filtering waste from the blood and maintaining the body’s critical balance of fluids, electrolytes (like sodium and potassium), and acid-base levels. They also produce hormones that help control blood pressure and stimulate red blood cell production, which prevents anemia. When this function is lost, waste products and excess fluid build up, leading to life-threatening complications. Renal support encompasses all strategies, from managing disease progression through diet and medication to active replacement therapies, designed to restore these lost functions.
Managing Kidney Disease Progression
Before kidney function requires active replacement, treatment focuses on slowing the disease’s progression and managing complications. This approach, called conservative management, reduces the workload on the remaining functional tissue. Dietary adjustments are a major component, limiting substances difficult for impaired kidneys to clear.
- Restricted protein intake, as protein metabolism creates nitrogenous waste products the kidneys must filter.
- Limited sodium intake to control fluid retention and manage high blood pressure.
- Restriction of foods high in phosphorus, which can lead to bone disease.
- Restriction of foods high in potassium, which can cause heart rhythm disturbances.
Medications control systemic issues that accelerate kidney damage. Blood pressure control is essential, often targeting below 130/80 mmHg, especially for those with diabetes. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) are frequently prescribed because they lower blood pressure and protect kidney tissue. Anemia is managed through iron supplementation or injections of erythropoietin, a hormone healthy kidneys produce to stimulate red blood cell creation.
Mechanical Blood Filtration
When conservative measures are no longer sufficient to sustain life or manage symptoms, mechanical blood filtration, known as dialysis, becomes necessary. Dialysis artificially removes waste products, excess fluid, and balances electrolytes in the blood. There are two primary forms: hemodialysis (HD) and peritoneal dialysis (PD).
Hemodialysis (HD)
HD involves diverting the patient’s blood outside the body to a machine called a dialyzer, often referred to as an artificial kidney. Blood is continuously pumped from the body, usually through a vascular access point, into the dialyzer. Inside, the blood flows on one side of a semipermeable membrane while a cleansing solution called dialysate flows on the other. Waste and excess fluid move across the membrane into the dialysate before the cleaned blood is returned to the body. This procedure is typically performed three times a week, lasting three to five hours per session. Treatments most commonly occur in a specialized dialysis center, but home hemodialysis is also an option.
Peritoneal Dialysis (PD)
PD uses the patient’s own abdominal lining, the peritoneum, as the natural filter instead of an external machine. A catheter is surgically placed into the abdomen, allowing dialysate fluid to be instilled into the peritoneal cavity. Waste and fluid pass across the peritoneal membrane into the dialysate. After a set “dwell time,” the fluid containing the filtered waste is drained and replaced with fresh dialysate. This method allows for more continuous filtration, which is gentler on the body and permits a less restricted diet compared to HD. PD is typically performed at home and offers greater flexibility, including manual exchanges (CAPD) or automated exchanges performed overnight (APD).
Kidney Replacement Surgery
Kidney transplantation involves a surgical procedure to implant a healthy kidney from a donor into the recipient. The new kidney takes over all the functions of the failed organs, offering independence from dialysis and a substantial improvement in quality of life. Donor organs come from two sources: a living donor or a deceased donor.
A living donor may be a family member, friend, or even an altruistic stranger. These transplants generally offer the best long-term patient and graft survival rates compared to deceased donor organs. Receiving a living donor kidney often allows the surgery to be scheduled electively, potentially before the recipient needs to start dialysis. Deceased donors provide kidneys allocated based on complex matching criteria, leading to a waiting period that can last months or years.
Recipients undergo an extensive evaluation to ensure they are healthy enough for the major surgery and to identify factors that could compromise the new organ. Following the transplant, the patient must take immunosuppressive medications for the rest of their life to prevent the immune system from rejecting the new kidney. While transplantation is a goal for many with ESRD, it is not medically appropriate or immediately available for every patient.