09.3 Renal replacement therapy

Renal Replacement Therapy Overview

• Renal Replacement Therapy (RRT) replaces kidney function in End-Stage Renal Disease (ESRD) patients.
• Methods include hemodialysis, peritoneal dialysis, and renal transplantation.
• Dialysis focuses on solute clearance and homeostasis.
• Transplantation offers a more complete restoration, including endocrine function.

Learning Objectives

• Objective 1: Understand the definition and clinical scope of RRT.
• Objective 2: Describe the principles of dialysis.
• Objective 3: Differentiate between hemodialysis and peritoneal dialysis.
• Objective 4: Explain the advantages and complications of renal transplantation.

Key Concepts

• Renal Replacement Therapy (RRT): Medical treatments for ESRD patients.
• Hemodialysis: Extracorporeal blood filtering through a dialyzer to remove toxins and correct imbalances.
• Peritoneal Dialysis: Intracorporeal dialysis, using the peritoneal membrane as a natural filter.
• Renal Transplantation: Surgical kidney replacement for ESRD patients.
• End-Stage Renal Disease (ESRD): Chronic kidney disease stage, where kidney function is insufficient without RRT.

Clinical Applications

• Case Study: 55-year-old ESRD patient transitioning from peritoneal dialysis to hemodialysis.
• Diagnostic Approach: Assessing eGFR (5-7 mL/min/1.73 m²) and symptoms like hyperkalemia, acidosis, or fluid overload.
• Treatment Options: Hemodialysis, peritoneal dialysis, and renal transplantation, based on patient needs.
• Complications/Management: Sepsis, vascular access failure (hemodialysis), and peritonitis (peritoneal dialysis) require preventive and management strategies.

Pathophysiology

• Mechanism: Dialysis works through diffusion and osmosis. Solutes move from higher to lower concentration across a semipermeable membrane.
• Hemodialysis: Blood is drawn, filtered through a dialyzer with countercurrent dialysate flow, enhancing solute clearance.
• Peritoneal Dialysis: Dialysate is introduced into the peritoneal cavity, using the peritoneal membrane as a filter to remove waste and excess fluid.

Pharmacology (Transplant Patients)

• Immunosuppressive Drugs: Calcineurin inhibitors (e.g., Cyclosporine, Tacrolimus), Corticosteroids (e.g., Prednisone), and Antiproliferative Agents (e.g., Mycophenolate Mofetil, Azathioprine).

Differential Diagnosis

• Chronic Kidney Disease (CKD): Progressive decline in kidney function, initially managed with lifestyle and medication.
• Acute Kidney Injury (AKI): Sudden kidney function loss, often temporary, requiring fluid resuscitation and, when necessary, temporary RRT.
• Polycystic Kidney Disease: Genetic disorder causing fluid-filled cysts in kidneys, managed with dialysis or transplantation in severe cases.

Investigations

• Blood Tests: Monitor serum creatinine, urea, potassium, bicarbonate, and hemoglobin.
• Imaging: Renal ultrasound or CT to evaluate kidney size, structure, and obstructions.
• Biopsy: Performed to assess rejection in kidney transplant patients.

Key Diagrams and Visuals

• Diagrams illustrate hemodialysis and peritoneal dialysis equipment, highlighting the process.

Summary and Key Takeaways

• Three main RRT methods: hemodialysis, peritoneal dialysis, and renal transplantation.
• Hemodialysis uses an extracorporeal dialyzer.
• Peritoneal dialysis uses the peritoneal membrane.
• Transplantation offers most comprehensive kidney function restoration, requiring lifelong immunosuppression.

Further Reading/References

• Brenner & Rector's The Kidney
• Nephrology Textbook
• National Kidney Foundation (NKF) Resources

This quiz focuses on Renal Replacement Therapy (RRT) for End-Stage Renal Disease (ESRD) patients. You will explore various methods of RRT, including hemodialysis, peritoneal dialysis, and renal transplantation, and examine their principles, advantages, and complications. Test your understanding of these vital kidney replacement methods.