Chronic Kidney Disease Overview

Approach to Chronic Kidney Disease

• Chronic kidney disease (CKD) often progresses to end-stage renal disease (ESRD), requiring renal replacement therapy (RRT).
• Patients with CKD frequently die from non-renal causes, particularly cardiovascular events.
• Early diagnosis of CKD is crucial to delay progression and prevent cardiovascular complications.

Defining CKD

• Kidney disease improving global outcomes (KDIGO) defines CKD as abnormalities in kidney structure or function lasting for ≥3 months, impacting health.
• National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (KDOQI) also defines CKD.
• CKD is diagnosed if kidney damage (structural or functional abnormality) persists for ≥3 months, with or without decreased glomerular filtration rate (GFR). This damage is confirmed through urinalysis, imaging studies, or renal biopsy.

CKD Criteria

• CKD is characterized by kidney damage or reduced kidney function, lasting ≥ 3 months.
• GFR must be less than 60 mL/minute/1.73 m2, with or without kidney damage.
• Also characterized by structural or functional abnormalities other than decreased GFR.

Pathophysiology of CKD

Initiating Mechanism

• CKD initiating factors vary with the underlying cause.
• Genetic abnormalities in kidney development contribute to some cases.
• Immune complex deposition during glomerulonephritis inflammation plays a role.
• Toxin exposure in renal tubules and interstitium can initiate disease.

Progressive Mechanism

• Nephron number reduction, influenced by hormones, cytokines, and growth factors, occurs.
• Initial short-term compensatory responses include hyperfiltration and hypertrophy of remaining functioning nephrons.
• These responses become maladaptive, leading to glomerular damage, sclerosis, and further nephron loss.
• A cascade of events including increased renin-angiotensin activity is involved.
• These factors contribute to the ultimate reduction in renal mass and progressive decline in renal function.

CKD Epidemiology

• In 2017, 850 million people globally had CKD, with a prevalence of 11.1%.
• Prevalence of CKD is significantly associated with diabetes, cancer, and HIV. In 2017:
  • Diabetes: 422 million
  • Cancer: 42 million
  • HIV/AIDS: 36.7 million
• CKD is an increasingly significant cause of death, now ranked in the top 19th, 11th and 5th positions globally (1990, 2019, 2040).

Etiology of CKD

• Diabetic glomerular disease
• Hypertensive nephropathy
• Primary glomerulopathy with hypertension
• Vascular and ischemic renal disease
• Glomerulonephritis
• Urinary tract disease
• Polycystic kidney disease
• Lupus & analgesic nephropathy
• Tubulointerstitial nephropathy

Risk Factors of CKD

Susceptibility

• Advanced age
• Reduced kidney mass
• Low birth weight
• Racial or ethnic minority status
• Family history
• Low socioeconomic status

Initiation

• Diabetes
• Hypertension
• Autoimmune disease
• Polycystic kidney disease
• Drug toxicity

Progression

• Hyperglycemia
• Elevated blood pressure
• Proteinuria
• Smoking

Significance of GFR and Albuminuria

• Glomerular Filtration Rate (GFR):
  • A measure of kidney function, reflecting the overall health of the kidneys.
  • Decreases in GFR correlate with worsening kidney disease symptoms and metabolic abnormalities.
  • GFR values less than 60 mL/min/1.73m2 indicate a high risk of CKD complications, including metabolic and cardiovascular issues, and possibly death.
• Albuminuria (or proteinuria):
  • A marker of chronic kidney damage.
  • The prognostic value of Albuminuria is in indicating the progression of CKD.
  • Albuminuria is an independent cardiovascular risk factor.
  • Methods such as the urine albumin to creatinine ratio (ACR) are used in diagnosis.

Normal GFR

• Normal GFR in young adults: 120-130 mL/min/1.73 m2
• GFR declines with age.
• GFR varies based on gender and body size.
• The annual mean GFR decline with age is approximately 1 mL/min/year/1.73 m2.
• Adult mean GFR of 70 mL/min/1.73m2 is achieved by age 70.

Clinical Evaluation

• History taking (past medical history of pregnancy, infections, drugs impacting kidneys)
• Physical examination (blood pressure, physical findings)
• Clinical evaluation
• Investigations (blood tests, urine analysis)

Investigations

• CBC
• Urinalysis (dipstick and microscopy)
• 24-hour urine protein
• Serum creatinine & Urea
• Coagulation profile
• Electrolytes (Na+, K+, Ca2+, PO4)
• Liver enzymes
• Vitamin B12, folate levels
• HbA1c

Renal USG

• B/L shrunken kidneys
• Asymmetry
• Scar from reflux nephropathy
• CKD with normal/large size kidney
  • Diabetic nephropathy
  • Amyloidosis
  • HIV nephropathy
  • Polycystic kidney disease, Renal biopsy is considered
• c/l in b/l small kidneys
• Uncontrolled hypertension
• Active UTI
• Bleeding diathesis

AKI vs. CKD

• Differentiate by detailed clinical history, sequential creatinine testing, and potentially Renal Ultrasound.
• CKD patients are at higher risk for acute kidney injury (AKI)

AKI on CKD

• AKI superimposed on CKD is associated with potential emergency.
• AKI can lead to rapid progression to end-stage renal disease (ESRD).
• Conditions that may lead to AKI include infections, drugs, hydration issues, or other renal problems.

Screening for CKD

• CKD screening of general population isn't advocated.
• High-risk groups for CKD screening include:
  • Patients with hypertension
  • Patients with diabetes
  • Patients with cardiovascular disease
  • Individuals with hematuria or proteinuria incidentally detected.
  • Patients taking nephrotoxic drugs
  • Patients with structural renal disease
  • A family history of kidney disease

Cardiovascular Complications in CKD

• Albuminuria is a major risk factor for cardiovascular disease.
• CKD frequently leads to cardiovascular events.
• Ischemic vascular disease (ischemia, often exacerbated by hypovolemia) and cardiac dysfunction (often leading to heart failure and fluid buildup), are common consequences.

Hypertension in CKD

• A common complication of CKD, often leading to left ventricular hypertrophy(LVH).
• Hypertension is a progression factor.
• Low blood pressure can also signal underlying issues with worsened prognosis.
• Systolic blood pressure is the recommended target for optimizing treatment.

KDIGO Guideline

• Blood pressure target (<140/90 mmHg or <130/80 mmHg) depends on urine albumin excretion.

Preferred Antihypertensive Agent

• ACE inhibitors or ARBs (angiotensin receptor blockers) are preferred initial agents.
• Add other agents as needed to reach BP goals.
• Consider diuretics if associated edema is present.

Management Of CKD

• Prevent disease progression by addressing contributing factors (diabetes, hypertension).
• Lowering protein and sodium intake.
• Promote lifestyle modifications, like increased physical activity and smoking cessation.
• Management of complications is tailored to Stage of CKD and include adjustments for medications.
• Medications that impact kidney function are chosen and adjusted for effectiveness in each patient scenario

Management of MBD-CKD

• Addressing mineral and bone disorders (MBD) are critical.
• Include Vitamin D supplements and/or analogs like Calcitriol or Paricalcitol
• Calcimimetics (e.g., Cinacalcet) are considered when Vitamin D analogs are insufficient.

Fluid and Electrolyte Abnormalities

• Fluid overload commonly necessitates diuretics.
• Hyponatremia treatment includes hydration restriction and potentially diuretics, if indicated.
• Hyperkalemia management involves dietary restrictions (avoiding high-potassium foods). Various medications may also be needed to lower potassium levels.

Metabolic Acidosis

• Impaired kidney function can lead to metabolic acidosis.
• Often co-occurs with other abnormalities such as hyperkalemia.
• Bicarbonate replacement is part of the treatment process.

Drug Dosing in CKD

• Drug selection and dosing are vital to reduce toxicity
• Drug dosing adjustments are critical for CKD patients.
• Factors for consideration include stage of CKD and presence (or not) of renal replacement therapy.

Anemia in CKD

• Reduced erythropoietin production by diseased kidneys is the most common cause of anemia.
• Management of anemia often involves erythropoiesis-stimulating agents.

Glycemic Control

• HbA1c target is <7% for those with diabetes.
• Insulin dose adjustments are required as kidney function worsens, and Metformin may need to be discontinued in patients with reduced kidney function.

Dialytic Therapy

• Dialytic therapies are implemented when conservative treatments are insufficient.
• Conditions like electrolyte imbalances, uremia, and fluid overload are managed through dialysis.
• Patients with CKD Stage 5 are often candidates for various dialysis procedures, including hemodialysis, continuous renal replacement therapy, or peritoneal dialysis.

This quiz covers the approach to chronic kidney disease (CKD), including its definitions, diagnostic criteria, and its implications on patient health. Understand the importance of early diagnosis and the risks associated with CKD, including cardiovascular complications. Test your knowledge on key concepts and definitions relevant to CKD.