Diabetic Nephropathy

Question 1

What are 5 pathological changes in diabetic nephropathy?

Answer 1

1. Initial Hyper-filtration/ Capillary hypertension, before all other changes
2. Glomerular BM thickens
3. Mesangial expansion
4. Podocyte injury
5. Glomerular sclerosis/ arteriosclerosis

(2-4 may not all be present, occur in different orders)

Question 2

Beyond what concentration does glucose remain in tubular fluid and why?

Answer 2

10mmol, as all SGLTs in PCT are saturated so no more glucose can be absorbed

Question 3

How does diabetes lead to hyperfiltration?

Answer 3

• More Na in tubular fluid used up to re-absorb Glucose
• Macula Densa senses low Na+in DCT and activates RAAS
• Leads to Efferent arteriole vasoconstriction and Afferent arteriole vasodilation

Question 4

What are 3 ways the Glomerular Filtration Barrier is damaged leading to Diabetic Nephropathy?

Answer 4

• High Intraglomerular pressure/ hyperfiltration
• Thickened Glomerular BM, so increased pore size
• Damage to podocytes

Question 5

List the 5 stages/ steps of Diabetic Nephropathy leading to End Stage Renal Disease

Answer 5

1. Hyperfiltration + Hypertrophy
2. Latent stage (Normal albuminuria, GBM thickening, Mesangial expansion)
3. Microalbuminuria (Normal GFR, Podocyte changes, slightly increased albuminuria, increased GBM thickening, Mesangial expansion)
4. Overt proteinuria (Falling GFR, Severely increased albuminuria, Hyalinosis of arterioles)
5. ESRD

Question 6

What is the 1st clinical sign of Diabetic Nephropathy?

Answer 6

Microalbuminuria

Question 7

Compare Microalbuminuria and Overt Proteinuria in;

• Detectability on standard urine dipstick
• Reversibility

Answer 7

Microalbuminuria;

• Not delectable on standard dipstick
• Potentially reversible

Overt Proteinuria;

• Is detectable on standard dipstick
• Not reversible, but can be slowed

Question 8

List 8 risk factors of Diabetic Nephropathy

Answer 8

• Genetics
• Ethnicity
• Hypertension
• Hyperglycaemia
• Increasing age
• Smoking
• Duration of diabetes
• High level of hyperfiltration

Question 9

What is the primary method of prevention of diabetic nephropathy?

Answer 9

• Tight blood glucose control

- Tight blood pressure control

Question 10

Blood glucose control won’t slow the decline in GFR once Overt Proteinuria develops.

How can Insulin injections/ pumps help in the Microalbuminaemia stage?

Answer 10

Can reverse initial hyperfiltration and delay microalbuminaemia

Question 11

Does RAAS affect Afferent or Efferent arteriole more?

Answer 11

Efferent

Question 12

Why don’t paediatricians see patients with Diabetic Nephropathy

Answer 12

Children get Type 1 Diabetes, but are adults by the time they develop the condition