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 Stage | GFR range (ml/min) | Kindey Damage |
---|---|---|
Stage 1 | >90 | Some sign of kidney damage on other tests |
Stage 2 | 60-90 | Some sign of kidney damage on other tests |
Stage 3a | 45-59 | Moderate Reduction |
Stage 3b | 30-44 | Moderate Reduction |
Stage 4 | 15-29 | Severe Reduction |
Stage 5 | <15 | Establised 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)