S8) Diabetes and Other Systemic Conditions Affecting the Kidney Flashcards
Describe the structure of the glomerular capillary wall
What is the commonest cause of ESRD (end stage renal disease)?
Diabetic nephropathy
Identify 5 pathological processes which occur in diabetic nephropathy
- Hyperfiltration / capillary hypertension (occurs first)
- GBM thickening (increases pore size)
- Mesangial expansion
- Podocyte injury
- Glomerular sclerosis / arteriolosclerosis
What causes afferent vasodilation in Diabetes?
- Hyperglycaemia
- Low NaCl delivery to macula densa
- High blood amino acid levels
What causes the arteriolosclerosis observed in diabetic nephropathy and what impact does this have?
Hyalinosis of arterioles which causes tissue ischaemia
The clinical signs and symptoms observed in diabetic nephropathy can be arranged into 5 stages.
Identify them
- Hyperfiltration & hypertrophy
- Latent stage
- Microalbuminuria (moderately increased albuminuria)
- Overt proteinuria (severely increased albuminuria)
- ESRD
What is observed in the latent stage of diabetic nephropathy?
- Normal albuminuria
- GBM thickening
- Mesangial expansion
What is observed in the third stage of diabetic nephropathy (microalbuminuria)?
- Variable mesangial expansion / sclerosis
- Increased GBM thickening
- Podocyte changes
- GFR normal
What is observed in the fourth stage of diabetic nephropathy (overt proteinuria)?
- Diffuse glomerular histopathological changes
- Worsening systemic hypertension
- Falling GFR
- Microvascular changes (hyalinosis of arterioles)
What is the first clinical sign of diabetic nephropathy?
Microalbuminuria (assuming isotope GFR not measured)
Overt proteinuria in the third stage of diabetes is detectable on conventional dipstick.
What is the expected value in a woman?
Proteinuria > 30 mg/mmol Cr (0–3.5mg/mmol Cr)
Overt proteinuria in the third stage of diabetes is detectable on conventional dipstick.
What is the expected value in a man?
Proteinuria > 30 mg/mmol Cr (0–2.5mg/mmol Cr)
What is the clinical significance of overt proteinuria?
- Average decline in GFR 12mls / min/ year (2 – 20 mls)
- Most patients reach end-stage kidney disease in 3-7 years
Identify 5 risk factors for diabetic nephropathy
- Genetic susceptibility
- Race
- Hypertension
- Hyperglycaemia
- Increasing age
Describe the primary prevention of diabetic nephropathy
- Tight blood glucose control < 48 mmol/mol (<6.5%)
- Tight blood pressure control