Microvascular Complications of Diabetes - Nephropathy

Question 1

is DN more common in T or T2 DM

Answer 1

• in T2DM around 20% have DN at diagnosis, half will develop it in the next 20 years
• in T1DM, rare in the first 5 years, and incidence rises in the next 10-15 years

Question 2

what is the leading cause of ESRF

Answer 2

diabetic nephropathy - inc prevalence of diabetes

Question 3

what happens to glucose filtration in DN

Answer 3

• normally all is reabsorbed
• as there is an excess inthe blood it spills over into the urine

Question 4

what is there an increasd risk of with DM

Answer 4

infection - pyelonephritis is common

Question 5

what is the classical pathological sign of DN in the kidneys

Answer 5

• renal papillary necrosis - often occurs in association with acute pyelonephritis
• the combination of vascular damage and inflammation results in ischaemia of the renal papilla - may infarct and slough off into the urinary tract

Question 6

what is the underlying cause of injury and inflammation

Answer 6

glucose sticking to proteins inthe blood - non enzymatic glycation

Question 7

what happens to the arteries

Answer 7

• glycation of the basemnet membrane of blood vessels thickens them
• the efferent arteriole in particular constricts, and the afferent one dilates in response - inc blood pressure in the glomerulus
• there is atherosclerosis in the arteries

Question 8

what is the first stage of hypertension in the glomerulus

Answer 8

• hyperfiltration - increased GFR
• there are normally no symptoms at this stage

Question 9

role of ACEi in DN

Answer 9

• very good use
• cause efferent arteriole vasodilation by inhibitng angiotensin II which causes efferent arteriole vasoconstriction (!) and reduce proteinuria

Question 10

what happens to the mesangial cells in DN

Answer 10

• Incipient stage: expands - diffuse glomerulosclerosis
• Overt stage: forms nodules - Kimmelsteil Wilson nodules

Question 11

what syndrome can DN lead to

Answer 11

• nephrotic syndrome
• this usually precedes ESRF by several years

Question 12

how long does it tend to take people to develop ESRF

Answer 12

around ten years

Question 13

what is used to screen for DN

Answer 13

ACR - increased

• microalbuminuria gives an early warning of impending renal problems
• macroalbuminuria is a sign of a v bad problem

Question 14

what values are considered microalbuminuria

Answer 14

30-300mg albumin/24h

Question 15

what is microalbuminuria an independent risk factor for

Answer 15

CV disease

Question 16

what would you do when you find a patient has microalbuminuria

Answer 16

Question 17

modifiable risk factors

Answer 17

• Hypertension
• Cholesterol
• Smoking
• Glycaemic control
• Albuminuria

Question 18

non modifiable risk factors

Answer 18

• Male sex
• Duration of diabetes
• Genetic predisposition

Question 19

management of DN

Answer 19

• glycaemic control
• anti-hypertensive - ACEi decrease blood pressure, and reduce proteinuria by reducing intra-glomerular pressure by causing efferent arteriole vasodilation
• lipid control
• manage risk factors

Question 20

what effect does proteinuria have on prognosis

Answer 20

dec in proteinuria slows progression

Question 21

blood pressure target for those with microalbuminuria

Answer 21

130/80 (140/80 would be a less aggressive target)