S8) Diabetes and Other Systemic Conditions Affecting the Kidney Flashcards
(38 cards)
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 - end stage renal disease
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
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
Referring to 5 options, describe the managment of microalbuminuria and proteinuria
- Inhibition of RAAS
- Tight blood pressure control < 130/75 mmHg
- Statin therapy
- CV risk management (exercise, diet, stop smoking)
- Moderate protein intake
Angiotensin II is released following renin release.
Identify 4 effects of this substance on the kidney
- Increases glomerular permeability to proteins
- Mesangial cell proliferation
- Increases mesangial matrix
- Constricts efferent glomerular arteriole
- Increases glomerular pressure
State 2 effects of RAAS inhibition in the management of diabetic nephropahty
- Reduces glomerular hyperfiltration (efferent > afferent arterioles)
- Reduces proteinuria & slows progression at stages 2 - 4 of diabetic nephropathy
What is the first renal sign of hypertensive renal disease / nephrosclerosis?
Microalbuminuria
Describe the general diagnosis of hypertensive nephrosclerosis
- Hypertension precedes proteinuria
- Long-term decline in GFR
- Often, left ventricular hypertrophy and hypertensive eye disease before developing kidney disease
How does the clinical presentation of renal artery stenosis differ from hypertensive nephrosclerosis?
- More acute hypertension
- More rapid decline in GFR
- Evidence of atherosclerosis elsewhere
- Acute worsening with RAAS-blockade
Describe the vascular changes of hypertensive nephrosclerosis
Vascular changes to renal arteries & arterioles:
- Fibroelastic intimal thickening → narrowing of lumen
- Hyalinosis of afferent arteriolar walls
Describe the glomerular changes of hypertensive nephrosclerosis
Glomerular changes secondary to ischaemia from vascular changes:
- Wrinkling of glomerular tuft
- Glomerulosclerosis (patchy)
