Understanding Chronic Kidney Disease

Sep 21, 2024

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Chronic Kidney Disease (CKD)

Definition

  • Chronic kidney disease: A condition with a decrease in kidney function over a minimum of three months.
  • Acute kidney injury: A deterioration in kidney function that occurs in less than three months.

Kidney Functions

  • Regulate blood content
    • Remove waste
    • Maintain electrolyte balance
    • Regulate water amount
    • Hormone production

Blood Flow & Filtration

  • Blood enters via the renal artery
  • Filtration occurs in glomeruli
  • Filtrate moves into the renal tubule
  • Glomerular filtration rate (GFR): Normal is 100-120 mL/min/1.73 m²

Causes of CKD

  • Hypertension

    • Thickening of artery walls -> narrow lumen -> ischemic injury
    • Macrophages & foam cells -> secrete growth factors -> glomerulosclerosis

  • Diabetes

    • Excess glucose -> non-enzymatic glycation -> hyaline arteriosclerosis
    • Hyperfiltration -> glomerulosclerosis

  • Other causes

    • Systemic diseases: Lupus, rheumatoid arthritis
    • Infections: HIV
    • Long-term medications: NSAIDs
    • Toxins: Tobacco

Effects & Complications

  • Azotemia: Accumulation of urea
    • Causes nausea, loss of appetite
    • Severe cases: Encephalopathy, hand tremors, coma, death
  • Pericarditis: Inflammation of heart lining
  • Bleeding tendency: Due to reduced platelet adhesion
  • Uremic frost: Urea crystal deposits in skin

Electrolyte & Hormone Imbalance

  • Hyperkalemia: Excess potassium, risk of cardiac arrhythmias
  • Hypocalcemia
    • Decreased vitamin D activation -> low calcium absorption
    • Leads to renal osteodystrophy (weak bones)
  • Hormonal Effects
    • Increased renin secretion -> hypertension
    • Reduced erythropoietin -> anemia

Diagnosis

  • GFR levels
    • Suspected CKD: GFR < 90 mL/min/1.73 m²
    • Irreversible damage: GFR < 60 mL/min/1.73 m²
  • Kidney biopsy: Check for glomerulosclerosis

Treatment

  • Managing underlying causes
  • Severe cases: Dialysis or kidney transplant

Summary

  • CKD is a decrease in GFR below 90 mL/min/1.73 m² over three months
  • Mainly caused by diabetes and hypertension
  • Complications include electrolyte imbalances, toxin accumulation, hypertension, bone abnormalities