# Lecture 9: Chronic Kidney Disease ## Unit 2.1: Renal System --- ## Learning Objectives By the end of this lecture, students will be able to: 1. Define chronic kidney disease and its staging criteria 2. Describe the epidemiology and major causes of CKD 3. Explain the pathophysiology of CKD progression 4. Describe the systemic complications of CKD 5. Explain the management strategies for CKD and its complications 6. Describe indications for renal replacement therapy --- ## Definition and Staging Chronic kidney disease represents a progressive and often irreversible decline in kidney function that affects millions of people worldwide. The Kidney Disease Improving Global Outcomes (KDIGO) guidelines establish clear diagnostic criteria requiring either a glomerular filtration rate below 60 mL/min/1.73m² or the presence of kidney damage markers persisting for at least three months. This duration requirement distinguishes CKD from acute kidney injury and ensures that transient changes do not result in misdiagnosis. Kidney damage markers encompass several categories beyond simple GFR reduction. Albuminuria at or above 30 mg/g creatinine indicates glomerular barrier dysfunction. Urine sediment abnormalities such as hematuria or casts suggest ongoing parenchymal disease. Electrolyte disturbances from tubular disorders, structural abnormalities detected on imaging, histologic changes on biopsy, and a history of kidney transplantation all qualify as damage markers that establish CKD diagnosis even when GFR remains above 60. The GFR staging system divides kidney function into six categories. Stage G1 represents normal or high GFR at 90 mL/min/1.73m² or above, though CKD is still diagnosed if damage markers exist. Stage G2 indicates mildly decreased function at 60-89, while G3a and G3b represent mild-moderate (45-59) and moderate-severe (30-44) decreases respectively. Stage G4 signifies severely decreased function at 15-29, and G5 defines kidney failure with GFR below 15. Albuminuria staging adds prognostic refinement beyond GFR alone. Category A1 represents normal to mildly increased albumin excretion below 30 mg/day or albumin-to-creatinine ratio below 30 mg/g. Category A2 indicates moderately increased albuminuria at 30-300, while A3 represents severely increased excretion above 300. The combination of higher GFR stage and higher albuminuria category predicts worse outcomes, creating a risk matrix that guides monitoring frequency and intervention intensity. Panel A: GFR staging on the vertical axis showing G1 (90 or above), G2 (60-89), G3a (45-59), G3b (30-44), G4 (15-29), and G5 (below 15) with decreasing kidney function indicated downward. Panel B: Albuminuria staging on the horizontal axis showing A1 (below 30 mg/g), A2 (30-300 mg/g), and A3 (above 300 mg/g) with increasing albuminuria indicated rightward. Panel C: Heat map color coding progressing from green (low risk) in upper left through yellow and orange (moderate risk) to red and dark red (high/very high risk) in the lower right. Panel D: Monitoring recommendations in each cell showing increased frequency of evaluation as risk category worsens from annual to multiple times per year. --- ## Epidemiology and Causes The global burden of CKD affects approximately 10-13% of the world's population, with prevalence in the United States reaching nearly 15% of adults. Despite these striking numbers, awareness remains dismally low, with fewer than 10% of affected individuals knowing they have CKD. This lack of awareness delays intervention and allows preventable progression. End-stage renal disease requiring dialysis or transplantation affects approximately 750,000 people in the US alone, with enormous personal and healthcare system costs. Diabetes mellitus stands as the leading cause of CKD, accounting for 40-50% of all cases. Diabetic nephropathy develops through a predictable sequence of hyperfiltration, microalbuminuria, overt proteinuria, and progressive GFR decline. Hypertension ranks second at 25-30%, causing nephrosclerosis through chronic vascular injury. Glomerulonephritis accounts for approximately 10%, encompassing both primary glomerular diseases and systemic conditions affecting the kidney. Polycystic kidney disease represents 3-5% of CKD cases, with its genetic basis distinguishing it from acquired causes. Other etiologies including obstructive uropathy, chronic pyelonephritis, and various systemic diseases comprise the remaining 10-15%. Several factors accelerate CKD progression beyond the underlying cause. Proteinuria represents the most important modifiable risk factor, with higher levels predicting faster decline. Uncontrolled hypertension perpetuates vascular injury and glomerular stress. Ongoing diabetic injury continues to damage nephrons if glycemic control remains poor. Episodes of acute kidney injury, once thought to resolve completely, now are recognized to increase CKD risk with each occurrence. Nephrotoxin exposure from NSAIDs, contrast agents, and other medications inflicts additional damage. Smoking accelerates progression through vascular effects, while obesity promotes hyperfiltration injury. Panel A: Pie chart of CKD etiologies showing diabetes as the largest segment (40-50%), followed by hypertension (25-30%), glomerulonephritis (10%), polycystic kidney disease (3-5%), and other causes (10-15%). Panel B: Global burden statistics showing approximately 10-13% worldwide prevalence, 15% US adult prevalence, and fewer than 10% awareness among affected individuals. Panel C: Vertical bar chart of modifiable risk factors for progression with proteinuria as the tallest bar, followed by hypertension, diabetes, AKI episodes, nephrotoxins, smoking, and obesity. Panel D: Risk factor icons showing protein droplet for proteinuria, blood pressure cuff for hypertension, glucose meter for diabetes, kidney with lightning bolt for AKI, pill bottle for nephrotoxins, cigarette for smoking, and weight scale for obesity. --- ## Pathophysiology of Progression The common pathway of CKD progression operates independently of the initial insult, explaining why diverse etiologies ultimately converge on similar outcomes. Initial nephron loss from any cause triggers compensatory changes in surviving nephrons that paradoxically contribute to further damage. This maladaptive response transforms a localized injury into progressive whole-kidney disease. Following nephron loss, remaining nephrons undergo hypertrophy and increase their individual filtration rates to maintain overall kidney function. This single-nephron hyperfiltration initially succeeds in preserving GFR but generates mechanical stress on glomerular capillaries. Elevated intraglomerular pressure injures the filtration barrier, promotes protein leakage, and triggers mesangial expansion. Over time, hyperfiltration-induced injury causes glomerulosclerosis in previously healthy nephrons, perpetuating a cycle of nephron loss and compensatory hyperfiltration. The renin-angiotensin-aldosterone system plays a central role in this destructive sequence. Angiotensin II preferentially constricts the efferent arteriole, raising intraglomerular pressure and exacerbating hyperfiltration injury. Beyond hemodynamic effects, angiotensin II promotes mesangial cell contraction, increases proteinuria, stimulates inflammatory cytokines and growth factors including TGF-β, and directly promotes collagen deposition. These actions explain why RAAS blockade provides renoprotection beyond blood pressure lowering alone. Proteinuria functions as both a marker and mediator of kidney damage. Filtered proteins that escape into the tubular fluid undergo uptake by proximal tubular cells. This abnormal protein load triggers inflammatory responses within tubular epithelium, releasing cytokines and chemokines that recruit inflammatory cells to the interstitium. Chronic tubulointerstitial inflammation progresses to fibrosis, with collagen deposition replacing functional nephrons with scar tissue. The degree of interstitial fibrosis on biopsy correlates more strongly with prognosis than glomerular findings alone. Panel A: Initial nephron loss leading to compensatory hyperfiltration in remaining nephrons shown as enlarged glomeruli with increased single-nephron GFR. Panel B: Destructive cycle showing increased intraglomerular pressure causing glomerular injury and proteinuria, leading to tubular protein uptake, interstitial inflammation, and fibrosis that causes further nephron loss. Panel C: RAAS activation pathway showing angiotensin II mediating efferent vasoconstriction, TGF-beta release, mesangial contraction, and pro-fibrotic effects that amplify injury. Panel D: Disease progression color gradient from yellow (early injury) through orange (inflammation) to brown (fibrosis), illustrating the convergent final pathway regardless of initial insult. --- ## Uremia and Systemic Complications As kidney function declines, the accumulation of uremic toxins produces a multisystem syndrome affecting virtually every organ. Neurologic manifestations range from subtle cognitive impairment to frank encephalopathy, with asterixis and confusion indicating severe uremia. Peripheral neuropathy causes sensory symptoms and weakness, while restless leg syndrome disrupts sleep and quality of life. Gastrointestinal effects include anorexia, nausea, vomiting, and dysgeusia that contribute to malnutrition. Uremic gastritis and colitis increase bleeding risk, compounded by platelet dysfunction. Cardiovascular disease represents the leading cause of death in CKD patients, far exceeding the risk from progression to dialysis. Traditional cardiovascular risk factors including hypertension, diabetes, and dyslipidemia occur with increased frequency. However, non-traditional factors unique to CKD amplify cardiovascular risk beyond what these conventional risks predict. Hyperphosphatemia, elevated FGF-23, chronic inflammation, and accumulated uremic toxins promote vascular calcification and accelerate atherosclerosis. Volume and pressure overload from sodium retention and hypertension lead to left ventricular hypertrophy that predisposes to arrhythmias and sudden death. Dermatologic manifestations include pruritus that can be debilitating, caused by calcium-phosphate deposition in skin, uremic toxins, and altered opioid receptor activity. In severe uremia, urea crystallizes on the skin as uremic frost, though this finding has become rare with earlier dialysis initiation. Skin hyperpigmentation results from retained urochrome pigments. Panel A: Neurologic manifestations showing encephalopathy with confusion and asterixis in the brain, peripheral neuropathy, and restless leg syndrome. Panel B: Cardiovascular manifestations showing pericarditis, left ventricular hypertrophy, accelerated atherosclerosis, and vascular calcification. Panel C: Gastrointestinal and dermatologic manifestations showing nausea, anorexia, uremic bleeding, pruritus with scratch marks, and skin hyperpigmentation. Panel D: Musculoskeletal and other manifestations showing renal osteodystrophy with fracture-prone bones, small scarred kidneys in center, and uremic red eye with band keratopathy. --- ## Mineral and Bone Disorder CKD-mineral and bone disorder encompasses the biochemical abnormalities, bone disease, and vascular calcification that develop as kidney function declines. This syndrome begins early in CKD but produces clinical consequences primarily in advanced stages. The interconnected pathophysiology involves vitamin D deficiency, phosphorus retention, hypocalcemia, and secondary hyperparathyroidism. The kidney's 1α-hydroxylase enzyme converts 25-hydroxyvitamin D to active 1,25-dihydroxyvitamin D (calcitriol). As functional renal mass declines, calcitriol production falls, reducing intestinal calcium absorption and causing hypocalcemia. Simultaneously, reduced nephron mass limits phosphorus excretion, leading to hyperphosphatemia. Both hypocalcemia and hyperphosphatemia stimulate parathyroid hormone secretion, producing secondary hyperparathyroidism. Elevated PTH maintains serum calcium by mobilizing calcium from bone but at the cost of progressive skeletal damage. FGF-23 emerges as an early marker of disturbed mineral metabolism, rising before detectable changes in calcium, phosphorus, or PTH. This phosphaturic hormone, secreted by osteocytes in response to phosphorus loading, initially maintains normal serum phosphorus by increasing fractional excretion. However, FGF-23 also suppresses calcitriol synthesis, contributing to vitamin D deficiency. Elevated FGF-23 independently predicts cardiovascular events and mortality in CKD. Renal osteodystrophy describes the spectrum of bone disease in CKD. High-turnover disease (osteitis fibrosa cystica) results from sustained PTH elevation, with increased osteoclast and osteoblast activity causing bone resorption and abnormal formation. Low-turnover disease includes adynamic bone disease, where oversuppression of PTH leaves bone formation inadequate to replace normal resorption. Osteomalacia results from defective mineralization of newly formed bone matrix. The distinction matters because treatment differs: high-turnover disease requires PTH suppression, while low-turnover disease may worsen with aggressive PTH lowering. Panel A: Central declining kidney function with decreased 1-alpha-hydroxylase leading to low calcitriol and decreased intestinal calcium absorption. Panel B: Phosphorus retention from reduced renal excretion combined with hypocalcemia stimulating parathyroid glands to secrete PTH, producing secondary hyperparathyroidism. Panel C: FGF-23 rising early from osteocytes in response to phosphorus loading, maintaining serum phosphorus initially but suppressing calcitriol synthesis. Panel D: Downstream effects showing osteitis fibrosa with ragged bone resorption surfaces, vascular calcification with calcium deposits in arterial walls, and fracture-prone skeleton. --- ## Hematologic Complications Anemia develops in virtually all patients with advanced CKD and significantly impairs quality of life. The primary mechanism involves decreased erythropoietin production by diseased kidneys. Erythropoietin, synthesized by peritubular interstitial cells in response to hypoxia, stimulates erythroid progenitor proliferation in bone marrow. As functioning renal mass declines, erythropoietin production becomes insufficient to maintain normal red cell mass. Multiple factors compound erythropoietin deficiency. Iron deficiency occurs frequently in CKD due to reduced absorption, chronic blood loss from uremic bleeding tendency and dialysis, and impaired iron utilization. Functional iron deficiency describes a state where iron stores appear adequate but cannot be mobilized effectively due to inflammation-induced hepcidin elevation. Uremic toxins directly suppress bone marrow erythropoiesis and shorten red blood cell survival. The resulting anemia is typically normocytic and normochromic, becoming clinically significant when GFR falls below 30-45 mL/min. Treatment begins with iron repletion, targeting ferritin above 100 ng/mL and transferrin saturation above 20%. Intravenous iron often proves necessary due to impaired oral absorption. Erythropoiesis-stimulating agents (ESAs) including epoetin alfa and longer-acting darbepoetin alfa effectively raise hemoglobin but carry risks of hypertension, thrombosis, and potentially accelerated tumor growth. Current guidelines recommend conservative hemoglobin targets of 10-11.5 g/dL rather than normalization. Newer hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI) such as roxadustat offer oral administration and may provide more physiologic erythropoietin stimulation. Beyond anemia, uremia impairs hemostasis through platelet dysfunction. Uremic toxins interfere with platelet adhesion and aggregation, while impaired von Willebrand factor function reduces interaction with exposed collagen. This bleeding tendency manifests as easy bruising, prolonged bleeding from cuts, and increased surgical bleeding risk. Desmopressin (DDAVP) provides temporary hemostatic improvement by releasing vWF from endothelial stores, while dialysis removes uremic toxins affecting platelet function. Panel A: Primary mechanism showing kidney cross-section with peritubular interstitial cells highlighted and decreased erythropoietin production as functional renal mass declines. Panel B: Contributing factors including iron deficiency (depleted stores), functional iron deficiency from hepcidin elevation, uremic toxin suppression of marrow, and shortened RBC lifespan. Panel C: Laboratory assessment showing ferritin target above 100 ng/mL and transferrin saturation target above 20%, with normocytic normochromic anemia pattern. Panel D: Treatment algorithm starting with iron repletion (IV often needed), progressing to ESA therapy (epoetin alfa or darbepoetin alfa) targeting hemoglobin 10-11.5 g/dL, with HIF-PHI agents (roxadustat) as an alternative oral pathway. --- ## Management: Slowing Progression The cornerstone of CKD management involves interventions that slow progression toward kidney failure. Blood pressure control provides fundamental renoprotection, with current guidelines recommending targets below 130/80 mmHg for most CKD patients. Even lower targets may benefit those with significant proteinuria, though excessive lowering risks hypoperfusion in patients with renovascular disease. RAAS blockade with ACE inhibitors or angiotensin receptor blockers provides benefits beyond blood pressure reduction alone. By blocking angiotensin II-mediated efferent arteriolar constriction, these agents reduce intraglomerular pressure and decrease proteinuria. The antiproteinuric effect represents a key mechanism of renoprotection, as reducing filtered protein decreases tubular injury and downstream fibrosis. Monitoring for hyperkalemia and creatinine elevation is essential, though small increases in creatinine (up to 30%) are expected and acceptable. Combination RAAS blockade with both ACE inhibitors and ARBs is not recommended due to increased adverse events without additional benefit. SGLT2 inhibitors have emerged as transformative agents for CKD management. Originally developed as diabetes medications, drugs like empagliflozin, dapagliflozin, and canagliflozin demonstrate remarkable renoprotection in both diabetic and non-diabetic CKD. Their mechanisms extend beyond glucose lowering to include reduced intraglomerular pressure through tubuloglomerular feedback modulation, decreased proteinuria, favorable metabolic effects, and reduced volume overload. Major trials demonstrate reduced CKD progression and cardiovascular events across a broad range of patients with albuminuric CKD. Glycemic control in diabetic CKD targets hemoglobin A1c around 7%, balancing benefits against hypoglycemia risk that increases as GFR declines. Metformin use becomes limited below GFR of 30 due to lactic acidosis risk. Lifestyle modifications including moderate dietary protein restriction (0.8 g/kg/day), sodium restriction below 2 g/day, smoking cessation, and weight management provide additional benefits in slowing progression. Panel A: Blood pressure control with target below 130/80 mmHg and RAAS blockade using ACE inhibitor or ARB showing mechanism of reduced efferent arteriolar constriction and lower intraglomerular pressure. Panel B: SGLT2 inhibitors showing reduced hyperfiltration through tubuloglomerular feedback modulation, with benefits in both diabetic and non-diabetic CKD. Panel C: Glycemic control targeting hemoglobin A1c around 7% with notation of metformin limitation below GFR of 30. Panel D: Lifestyle modifications including sodium restriction below 2 g/day, moderate protein intake (0.8 g/kg/day), smoking cessation, and weight management, with arrows pointing to reduced proteinuria and slowed GFR decline outcomes. --- ## Management of Complications Effective CKD management requires attention to the multiple complications that develop as kidney function declines. CKD-MBD management aims to control phosphorus, maintain calcium balance, and prevent excessive PTH elevation. Dietary phosphorus restriction provides first-line control, though compliance proves challenging given phosphorus ubiquity in processed foods. Phosphate binders taken with meals prevent intestinal phosphorus absorption. Calcium-based binders (calcium carbonate and calcium acetate) are inexpensive but risk hypercalcemia and may promote vascular calcification. Non-calcium binders including sevelamer and lanthanum avoid these risks and are increasingly preferred. Vitamin D supplementation addresses deficiency, with native vitamin D (cholecalciferol or ergocalciferol) appropriate for early CKD and active vitamin D (calcitriol) or analogs necessary when 1α-hydroxylase activity becomes insufficient. Calcimimetics such as cinacalcet lower PTH by increasing parathyroid calcium receptor sensitivity, useful when hyperparathyroidism persists despite other measures. Metabolic acidosis develops in CKD due to reduced ammonium excretion and buffering capacity. When serum bicarbonate falls below 22 mEq/L, oral sodium bicarbonate supplementation maintains acid-base balance and may independently slow CKD progression. Typical doses range from 0.5 to 1 mEq/kg/day. Volume management becomes increasingly challenging as kidney function declines. Sodium restriction and loop diuretics address volume overload, though diuretic efficacy diminishes as GFR falls. Thiazide diuretics lose effectiveness below GFR of 30, making loop diuretics the preferred agents in advanced CKD. Cardiovascular risk reduction follows general principles with some CKD-specific considerations. Statin therapy benefits patients not yet on dialysis, though data for dialysis patients are less compelling. Aspirin use follows standard cardiovascular guidelines while acknowledging increased bleeding risk. Smoking cessation receives strong recommendation given accelerated vascular disease in CKD. Panel A: CKD-MBD management showing phosphate binder options (calcium carbonate, sevelamer, lanthanum) taken with meals, vitamin D supplementation, and calcimimetics for PTH control. Panel B: Acidosis management with oral sodium bicarbonate targeting serum bicarbonate above 22 mEq/L, with typical doses of 0.5-1 mEq/kg/day. Panel C: Volume management showing sodium restriction and loop diuretics as preferred agents in advanced CKD, with thiazides losing effectiveness below GFR of 30. Panel D: Cardiovascular risk reduction showing statin therapy for non-dialysis CKD, aspirin per standard guidelines with bleeding risk awareness, and smoking cessation recommendation. --- ## Medication Considerations in CKD Safe prescribing in CKD requires systematic attention to altered drug pharmacokinetics. The CKD-EPI equation provides GFR estimates for dose adjustment decisions. Renally cleared drugs require reduced doses or extended intervals to prevent accumulation. Active metabolites of hepatically metabolized drugs may also accumulate, requiring adjustment even when parent drugs undergo non-renal elimination. Published dosing guidelines and pharmacy consultation assist with complex regimens. Several drug classes require particular caution or avoidance in CKD. NSAIDs inhibit prostaglandin-mediated afferent arteriolar dilation, reducing GFR and risking acute kidney injury. They also promote hyperkalemia and sodium retention. Metformin accumulation risks lactic acidosis, limiting its use below GFR of 30 (with many practitioners stopping below 45). Gadolinium-based contrast agents risk nephrogenic systemic fibrosis in severe CKD, a progressive fibrosing condition affecting skin and internal organs. Aminoglycosides cause nephrotoxicity through tubular injury. Bisphosphonates may accumulate and are generally avoided below GFR of 30. Oral sodium phosphate bowel preparations can cause acute phosphate nephropathy. Iodinated contrast for CT imaging poses particular challenges. Risk increases significantly below GFR of 45 and especially below 30. Prevention strategies include adequate hydration with intravenous normal saline before and after contrast exposure, using the minimum contrast dose necessary, and temporarily holding potentially interacting medications. Whether holding ACE inhibitors or ARBs reduces risk remains controversial. Panel A: Dose adjustment principle showing kidney with declining GFR and corresponding dose reduction curves for renally cleared drugs and active metabolites. Panel B: Drugs to avoid or use cautiously including NSAIDs (reduce GFR, hyperkalemia), metformin (lactic acidosis below GFR 30), and gadolinium (nephrogenic systemic fibrosis risk below GFR 30). Panel C: Additional caution drugs including aminoglycosides (nephrotoxicity), bisphosphonates (accumulation below GFR 30), and oral phosphate bowel preparations (acute phosphate nephropathy). Panel D: Contrast precaution protocol showing IV hydration before and after exposure, minimum contrast dose, and temporary hold of potentially interacting medications. --- ## End-Stage Kidney Disease End-stage kidney disease (ESKD) is defined by GFR below 15 mL/min/1.73m² or the need for renal replacement therapy. Symptoms prompting dialysis initiation include uremic manifestations such as refractory nausea, encephalopathy, or pericarditis; volume overload unresponsive to diuretics; hyperkalemia or acidosis not controlled with medical management; and declining nutritional status despite adequate intake. Preparation for ESKD should begin well before dialysis becomes necessary. Patient education about treatment options ideally starts when GFR falls below 30, allowing time for informed decision-making. Modality selection between hemodialysis, peritoneal dialysis, and transplantation reflects patient preferences, lifestyle considerations, and medical factors. For patients choosing hemodialysis, arteriovenous fistula creation should occur six months before anticipated need to allow maturation. Transplant evaluation should proceed early in appropriate candidates, as preemptive transplantation (before dialysis) offers the best outcomes. Renal replacement therapy options include hemodialysis, peritoneal dialysis, kidney transplantation, and conservative management. Each approach has distinct advantages, limitations, and requirements. The optimal choice varies among patients based on medical, social, and personal factors. Panel A: GFR 30 milestone showing patient education initiation and modality discussion covering hemodialysis, peritoneal dialysis, transplantation, and conservative management options. Panel B: GFR 20 milestone showing vascular access planning for hemodialysis and transplant referral for appropriate candidates. Panel C: GFR 15-20 milestone showing arteriovenous fistula creation with six months allowed for maturation, and dialysis initiation criteria below GFR 15 including uremic symptoms, refractory volume overload, refractory hyperkalemia, refractory acidosis, and declining nutritional status. Panel D: Conservative management shown as a parallel pathway focusing on symptom management and quality of life for patients with limited life expectancy or personal preference against dialysis. --- ## Dialysis and Transplantation Hemodialysis remains the most common renal replacement modality, using an external circuit to filter blood across a semipermeable membrane. Vascular access options include arteriovenous fistulas (surgically created connections between artery and vein), arteriovenous grafts (synthetic conduits when native fistulas are not feasible), and central venous catheters (for urgent or temporary access). Fistulas provide the best patency, lowest infection rates, and optimal outcomes but require surgical creation and months of maturation. Standard hemodialysis schedules involve three sessions weekly lasting three to four hours each. Complications include intradialytic hypotension, access infections and thrombosis, and difficulties achieving adequate volume and solute clearance. Peritoneal dialysis utilizes the peritoneal membrane as the dialysis surface, with dialysate instilled into the peritoneal cavity through a surgically placed catheter. Continuous ambulatory peritoneal dialysis (CAPD) involves manual exchanges performed four times daily, while automated peritoneal dialysis (APD) uses a cycler machine for overnight exchanges. Home-based treatment offers lifestyle flexibility and provides more hemodynamic stability than intermittent hemodialysis. Peritonitis represents the major complication, presenting with cloudy dialysate and abdominal pain. Catheter dysfunction, hernias, and eventual membrane failure limit long-term use. Kidney transplantation provides superior outcomes compared to dialysis, with better survival, quality of life, and cost-effectiveness over time. Living donor transplantation offers the best results, followed by deceased donor transplantation. However, organ shortage results in lengthy waitlist times, and not all patients qualify as transplant candidates. Lifelong immunosuppression carries risks of infection, malignancy, and medication toxicities. Conservative management without dialysis represents a valid choice for some patients, particularly those with limited life expectancy from comorbidities or personal preferences against invasive treatment. This approach focuses on symptom management and quality of life rather than life prolongation. Panel A: Hemodialysis showing patient connected to dialysis machine with vascular access types (AV fistula, synthetic graft, central venous catheter), frequency of 3x/week for 3-4 hours, and complications including intradialytic hypotension and access infections. Panel B: Peritoneal dialysis showing abdominal catheter with CAPD (manual exchanges 4x daily) and APD (overnight cycler), home-based flexibility, and peritonitis as the major complication. Panel C: Kidney transplantation showing surgical placement in pelvis, lifelong immunosuppression, superior outcomes compared to dialysis, and living donor as offering the best results. Panel D: Conservative management showing comfort-focused palliative approach for patients with limited life expectancy or preference against invasive treatment, emphasizing symptom management and quality of life. --- ## Summary Chronic kidney disease is defined by GFR below 60 or kidney damage persisting for at least three months, with staging by both GFR category (G1-G5) and albuminuria category (A1-A3). Diabetes accounts for 40-50% of cases and hypertension for 25-30%, making these the predominant causes worldwide. The universal progression pathway involves nephron loss leading to compensatory hyperfiltration, which causes proteinuria and ultimately fibrosis regardless of the initial insult. Systemic complications include anemia from erythropoietin deficiency, CKD-MBD with secondary hyperparathyroidism, cardiovascular disease as the leading cause of death, and the multisystem uremic syndrome. Management priorities focus on slowing progression through blood pressure control, RAAS blockade, and SGLT2 inhibitors, while also addressing complications with iron and ESAs for anemia, phosphate binders and vitamin D for mineral bone disorder, and bicarbonate for acidosis. End-stage kidney disease is defined by GFR below 15 or the need for dialysis. Treatment options include hemodialysis, peritoneal dialysis, kidney transplantation, or conservative management. Transplantation provides superior outcomes when feasible, and early referral for evaluation is recommended for appropriate candidates. --- ## Key Terms | Term | Definition | |------|------------| | Chronic kidney disease | Kidney damage or GFR below 60 persisting for at least three months | | End-stage kidney disease | GFR below 15 or requiring dialysis | | Uremia | Clinical syndrome resulting from accumulation of uremic toxins | | CKD-MBD | Mineral and bone disorder associated with CKD, including secondary hyperparathyroidism | | Secondary hyperparathyroidism | Elevated PTH secretion in response to hypocalcemia and hyperphosphatemia | | Erythropoietin | Hormone produced by kidneys that stimulates red blood cell production | | RAAS blockade | Treatment with ACE inhibitor or ARB to reduce proteinuria and slow progression | | Hemodialysis | Blood purification using an external semipermeable membrane | | Peritoneal dialysis | Dialysis using the peritoneal membrane as the filtration surface | --- *This content is subject to the [MIT License](https://opensource.org/licenses/MIT). © 2024–2026 Hibbert School of Medicine.*