Chronic Kidney Disease

Question 1

Define

Answer 1

Impaired renal function for >3 months based on abnormal structure or function, or GFR <6mL/min/1.73m2 for >3 months With or without evidence of kidney damage

• 5 stages (symptoms usually occur only once stage 4 is reached)

Classification of CKD

Stage 1: Normal

eGFR > 90 ml/min per 1.73 m2 with other evidence of CKD (microalbuminuria, proteinuria, haematuria, structural abnormalities, biopsy showing glomerulonephritis)

Stage 2: Mild Impairment

eGFR 60-89 ml/min per 1.73 m2 with other evidence of CKD

Stage 3a: Moderate Impairment

eGFR 45-59 ml/min per 1.73 m2

Stage 3b: Moderate Impairment

eGFR 30-44 ml/min per 1.73 m2

Stage 4: Severe Impairment

eGFR 15-29 ml/min per 1.73 m2

Stage 5: Established Renal Failure

eGFR < 15 ml/min per 1.73 m2 or on dialysis

Question 2

Causes

Answer 2

In developed countries it is mainly associated with:

• Age
• Diabetes mellitus
• Hypertension
• Obesity
• Cardiovascular disease

Other risk factors:

• Arteriopathic renal disease
• Nephropathies
• Family history
• Neoplasia
• Myeloma
• Systemic disease (e.g. SLE)
• Smoking
• Chronic use of NSAIDs

Question 3

Causes

Answer 3

• DM, HTN, CV disease (IHD, peripheral vascular disease
• Structural renal disease, e.g. stones or BPH
• Recurrent UTIs or childhood history of vasicoureteric reflux Multisystem disorders which could involve kidney (e.g. SLE) FHx of ESRF or hereditary disease e.g. APKD

Question 4

Epidemiology

Answer 4

>110 per million per year Higher incidence in Asian immigrants

Question 5

Symptoms

Answer 5

Identify possible causes: e.g. previous UTIs, LUTS, PMH of ↑BP/DM/IHD, systemic disorder, renal colic
Check FHx and drug history

• Uremic symptoms → anorexia, vomiting, restless legs, fatigue, weakness, pruritus, bone pain
• Later: diarrhoea, drowsiness, convulsions, coma
• Amenorrhea in women, impotence in men
• ±Oliguria, dyspnoea, ankle swelling

Question 6

Signs

Answer 6

Physical examination rarely reveals many clues

May show signs of underlying disease (e.g. SLE)

May show complications of CKD (e.g. anaemia)

Signs of CKD:

Skin pigmentation

Excoriation marks

Pallor

Hypertension

Peripheral oedema

Peripheral vascular disease

Question 7

Investigations

Answer 7

Assessment of Renal Function

• Urea - not ideal because it varies massively depending on hydration status and diet
• Creatinine - useful but has limitations. Renal function can drop considerably with minimal change in serum creatinine
• Isotopic GFR - GOLD STANDARD but expensive

Biochemistry

• Glucose - check for undiagnosed diabetes and diabetic control
• Potassium - raised
• Also check sodium, bicarbonate, calcium, phosphate

Serology

• Antibodies
• ANA - SLE
• c-ANCA - granulomatosis with polyangiitis (Wegener’s)
• Anti-GBM - Goodpasture’s syndrome
• Hepatitis serology
• HIV serology

Urinalysis

• Check for proteinuria/haematuria
• 24 hr urine collection
• Serum or urine protein electrophoresis - check for multiple myeloma

Imaging

Ultrasound - check for structural abnormalities

CT/MRI

X-Ray KUB - check for stones

Renal Biopsy