Chronic kidney disease

Question 1

Define chronic kidney disease

Answer 1

A pathological abnormality of the kidney such as haematuria and or proteinuria

Or

A reduction in the GFR to 60mL/minute/1.73m² for >3months

Question 2

What is the most common cause of CKD?

Answer 2

Diabetes

1/3 of patients with diabetes will develop kidney disease

Second to DM is hypertension

Other causes: PKD, obstructive uropathy, nephrotic and nephritic conditions

Question 3

Discuss the pathophysiology of CKD

Answer 3

Renal injury causes an icnreased in intra-glomerular pressure and causes hypertrophy

• Hyalinisation of the glomeruli occurs
• Renal injury results in angiotensin II production which causes TGF beta upregulation - this ptomotes collagen synthesis and scarring
• All forms of CKD are associated with tubulo-interstitial disease due to hypoxia and infiltration of inflammatory mediators

Question 4

Discuss clinical classification of CKD

Answer 4

• Evidence of kidney damage based on pathological diagnosis
• Abnormalities in radiological imaging
• Laboratory evidence of kidney damage e.g. haematuria and proteinuria
• Redcution in GFR to <60ml/min/1.73m² for >3months

Question 5

What are the stages of CKD?

Answer 5

1. Kidney damage + normal GFR >90
2. Kidney damage + mild decrease in GFR 60-89
   3a. Kidney damage + moderate decrease in GFR 45-59
   3b. Kidney damage + moderate decrease in GFR 30-44
3. Kidney damage + severe decrease in GFR 15-29
4. Failure (ESRD) with a GFR of <15

Question 6

Discuss diagnosis of CKD

Answer 6

Most are asymptomatic

Hx: fatigue, oedema, anorexia for meat and high protein food, nausea, vomiting, pruritis

Examination:

• Fundoscopy to look for small vessel disease - diabetic retinopathy
• Men: prostate examination
• Glomerular nephrotic and nephritic disease - hypertension, perio-orbital and peripheral oedema, rashes, arthritis,
• Foamy urine - protein +++
• Tea coloured urine if haematuria

Question 7

Discuss investigations for CKD

Answer 7

• Serum creatinine and GFR
• Nephrotic syndrome = >3.5g protein in 24hr urine collection
• Non-nephrotic sydromes = proteinruia of 1000mg/day is associated with a more rapid progression to stage 5 ESRD
• Renal biopsy
• X-ray if kidney stones suspected
• MRI if cancer suspected

Question 8

What are the risk factors for CKD?

Answer 8

• Diabetes
• Hypertension
• 50+
• Childhood KD
• Black/hispanic
• Male (weak)

Question 9

Outline clinical investigation findings associated with CKD

Answer 9

• Microalbuminuria: 30-300mg/ g creatinine/day
• Proteinuria: >300mg/day
• Haematuria: >3 RBCs

Question 10

Differentials for CKD?

Answer 10

1. Diabetic kidney disease
2. Hypertensive nephrosclerosis
   - Ishaemic nephropathy