Renal System >
Chronic Kidney Disease (CKD)

“Chronic reduction in renal function (over 3 months). Progressive and generally irreversible.”

Risk Factors
  • Modifiable:
    • Smoking
    • Medications that affect Kidney function
  • Non-Modifiable:
    • Older Age
    • Hypertension
    • Diabetes
    • Underlying Kidney disease – Polycystic kidney disease, chronic glomerylonephritis, chronic pyelonephritis.
Aetiology
  • Commonly caused by co-existing underlying conditions, including:
    • Diabetes (diabetic nephropathy)
    • Hypertension
    • Chronic glomerulonephritis
    • Autosomal dominant polycystic kidney disease (ADPKD)
    • Chronic pyelonephritis
Pathophysiology

Nephron loss → nephron hypertrophy & ­↑ arterial pressure → ­­↑ glomerular pressure & hyperfiltration → glomerulosclerosis → further nephron loss (vicious cycle)

Clinical Presentation
  • Usually diagnosed on routine testing and symptoms occurring by stage 4:
    • Uraemia – Pruritis, weight loss, confusion, paresthesia, lethargy, pale skin
    • Protein loss & Na retention – polyuria, polydipsia, oliguria, shortness of breath
    • Hyperkalaemia – palpitations, arrhythmias (tall T waves and widened QRS)
    • Acidosis – SOB, confusion, Kussmaul’s respiration for compensation
    • Anaemia – SOB, lethargy, faintness, tinnitus, pallor, tachycardia
    • Vitamin D deficiency – renal osteodystrophy, bone pain, osteomalacia
    • Hypercalcaemia – bone pain, excessive thirst, digestive problems, weakness
Investigations
  • Bloods:
    • Urea and Electrolytes – eGFR used to diagnose and stage CKD. 2 tests over 3 months required.
  • Imaging:
    • Bone X-Ray – Any renal osteodystrophy?
    • Abdominal X-Ray – any calcification from stones?
  • Special:
    • Urinalysis – assess for haematuria (1 + significant)
    • Albumin: creatinine ratio (ACR) – assess for proteinuria (dipstick not sufficient).
      • ACR 30-300mg/g for >3 months indicates CKD
Diagnosis
CDK StageGFR range (ml/min)Kindey Damage
Stage 1>90Some sign of kidney damage on other tests
Stage 260-90Some sign of kidney damage on other tests
Stage 3a45-59Moderate Reduction
Stage 3b30-44Moderate Reduction
Stage 415-29Severe Reduction
Stage 5<15Establised Renal Failure → Dialysis or Kidney transplant may be needed.

If there is no sign of kidney damage (e.g. no proteinuria or haematuria) and eGFR is only slightly reduced (eGFR 60-90) then there is no CKD.

Management
  • Conservative:
    • Lifestyle advice – exercise, good diet and weight control
    • Stop smoking
  • Medical:
    • Optimise control of diabetes/hypertension and treat underlying causes
    • Treat complications:
      • Oral sodium bicarbonate for metabolic acidosis
      • Iron for Anaemia
      • Active vitamin D
    • Dialysis treatment
  • Surgical:
    • Kidney Transplantation
Complications
  • Metabolic acidosis (decreased H+ excretion & HCO3- reabsorption)
  • Hyperkalaemia (↓ K loss from nephron), anaemia (decreased EPO)
  • Renal bone disease (low calcitriol & secondary hyperparathyroidism)
  • Hypertension (fluid overload)
  • Peripheral neuropathy (electrolytes imbalance)

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