Chronic Kidney Disease (CKD)
Definition | Classification | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Patient Advice
Definition
Chronic Kidney Disease (CKD) is a long-term condition defined as the presence of kidney damage or reduced kidney function (eGFR < 60 mL/min/1.73 m²) for a duration of at least 3 months. It is associated with an increased risk of cardiovascular disease and progression to kidney failure.
Classification
CKD is classified based on a combination of estimated glomerular filtration rate (eGFR) and urinary albumin:creatinine ratio (ACR):
| eGFR Category | eGFR (mL/min/1.73 m²) | ACR A1 (<3 mg/mmol) |
ACR A2 (3–30 mg/mmol) |
ACR A3 (>30 mg/mmol) |
|---|---|---|---|---|
| G1: Normal or High | ≥ 90 | Low Risk | Moderate Risk | High Risk |
| G2: Mild Reduction | 60–89 | Low Risk | Moderate Risk | High Risk |
| G3a: Mild to Moderate Reduction | 45–59 | Moderate Risk | High Risk | Very High Risk |
| G3b: Moderate to Severe Reduction | 30–44 | High Risk | Very High Risk | Very High Risk |
| G4: Severe Reduction | 15–29 | Very High Risk | Very High Risk | Very High Risk |
| G5: Kidney Failure | < 15 | Very High Risk | Very High Risk | Very High Risk |
Aetiology
- Diabetes Mellitus: Leading cause of CKD globally.
- Hypertension: Second most common cause, leading to chronic ischaemia.
- Glomerulonephritis: Chronic inflammation of glomeruli.
- Polycystic Kidney Disease: A genetic cause of CKD.
- Recurrent Urinary Tract Infections (UTIs): Leading to scarring.
Pathophysiology
CKD results from a combination of structural and functional damage to nephrons, leading to:
- Loss of filtration capacity, causing reduced GFR.
- Accumulation of toxins such as urea and creatinine.
- Progression to end-stage renal disease if untreated.
Risk Factors
- Diabetes and hypertension.
- Age over 60 years.
- Family history of CKD.
- Obesity and smoking.
Signs and Symptoms
- Fatigue and weakness.
- Swelling of the ankles, feet, or hands (oedema).
- Shortness of breath due to fluid overload.
- Persistent or worsening high blood pressure.
Investigations
- eGFR: Measure kidney function; repeat after 2 weeks if abnormal.
- Urinary ACR: Identify albuminuria; repeat if 3–70 mg/mmol, or manage if ≥70 mg/mmol.
- Blood Tests: Serum creatinine, HbA1c, lipid profile.
- Renal Ultrasound: Indicated if structural abnormalities are suspected.
Management
Primary Care:
- Optimise blood pressure control (target <140/90 mmHg).
- Prescribe ACE inhibitors or ARBs for proteinuria.
- Advise on lifestyle changes, including smoking cessation and weight loss.
When to Refer to Secondary Care:
- eGFR <30 mL/min/1.73 m² (G4 or G5).
- ACR ≥70 mg/mmol.
- Persistent haematuria with no identifiable cause.
- Rapidly declining kidney function (eGFR decline >5 mL/min/1.73 m² in 1 year).
Patient Advice
- Adhere to prescribed medication and follow dietary advice (e.g., low salt).
- Monitor blood pressure regularly at home.
- Attend annual reviews to monitor kidney function and cardiovascular risk.
- Report signs of worsening, such as swelling, reduced urine output, or breathlessness.
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