S8) Diabetes and Other Systemic Conditions Affecting the Kidney Flashcards
Describe the structure of the glomerular capillary wall
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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) → hypertrophy & increased GFR
- GBM thickening (increases pore size)
- Mesangial expansion
- Podocyte injury
- Glomerular sclerosis / arteriolosclerosis
What causes afferent vasodilation in Diabetes?
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- Hyperglycaemia
- Low NaCl delivery to macula densa
- High blood amino acid levels
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What causes the arteriolosclerosis observed in diabetic nephropathy and what impact does this have?
Hyalinosis of arterioles which causes tissue ischaemia
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The clinical signs and symptoms observed in diabetic nephropathy can be arranged into 5 stages.
Identify them
- Hyperfiltration & hypertrophy → increased GFR
- 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
![](https://s3.amazonaws.com/brainscape-prod/system/cm/330/401/705/a_image_thumb.png?1510743396)
What is observed in the third stage of diabetic nephropathy (microalbuminuria)?
- Variable mesangial expansion / sclerosis
- Increased GBM thickening
- Podocyte changes
- GFR normal
![](https://s3.amazonaws.com/brainscape-prod/system/cm/330/401/706/a_image_thumb.png?1510743449)
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)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/330/401/707/a_image_thumb.png?1510743463)
What is the first clinical sign of diabetic nephropathy?
- Microalbuminuria (assuming isotope GFR not measured)
- Tells su theres GBM thickening and mesangial expansion
- Important we detect this as not much we can do once we see increases in protein in urine - potentially reversible at this point
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?
- Normal GFR and proteinuria < 100 mg/mmol = mild kidney disease EXCEPT in diabetes
- Average decline in GFR 12mls / min/ year (2 – 20 mls)
- Most patients reach end-stage kidney disease in 3-7 years
Identify 7 risk factors for diabetic nephropathy
- Genetic susceptibility
- Race
- Hypertension
- Hyperglycaemia
- Increasing age
- Smoking
- Duration of diabetes
Describe the primary prevention of diabetic nephropathy
- Tight blood glucose control < 48 mmol/mol (<6.5%)
- Tight blood pressure control
Tight glycaemic control involves multiple injections or insulin pump to achieve a near normal blood glucose.
Describe 4 effects of this
- Can reverse initial hyperfiltration
- Can delay microalbuminuria
- Can reduce microalbuminuria over 2 years treatment period
- Doesn’t slow GFR loss once overt proteinuria develops