diabetic nephropathy and its pathophysiology

Question 1

diabetic nephropathy is the leading cause of

Answer 1

end stage renal failure in the developed world

Question 2

diabetic nephropathy is also known as

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kimmelstein-wilson nodules or nodular glomeruloscelrosis

Question 3

general overview of diabetic nephropathy

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progressive kidney disease caused by damage to the capillaries in the kidney glomeruli, characterised by nephrotic syndrome and diffuse scarring of the glomeruli

Question 4

each kidney has millions of

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nephrons each of which are supplied by a tiny capillary bed called a glomeruli

Question 5

the arteriole approaching the glomeruli is called the

Answer 5

afferent arteriole

Question 6

the arteriole exiting the glomeruli is called the

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efferent arteriole

Question 7

glomeruli are

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tiny cluster of capillaries which are physically supported by messangial cells

Question 8

when blood is filtered it moves through

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the endothelium lining the capillary then through the basement membrane then through the epithelium lining the nephron and then finally into the nephron itself where it is called a filtrate

Question 9

the endothelium has

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pores that keeps cells from entering the filtrate

Question 10

the basement membrane is

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negatively charged which repels other negatively charged molecules and proteins such as albumin preventing it from entering the filtrate

Question 11

the epithelium has

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podocytes which create filtration slits via there foot processes

Question 12

in diabetes mellitus

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there is excess glucose in the blood so when the blood gets filtered through the kidney some of the excess glucose spills into the urine causing glycosuria

Question 13

also when there is excess glucose in the blood it starts to

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stick to proteins in a process called non-enzymatic glycation

Question 14

because glucose can get through the endothelium

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in hyperglycaemic states non-enzymatic glycation can involve the basement membrane of small blood vessels which makes it thicker

Question 15

the process of non-enzymatic glycation of the basement membrane particularly affects the

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efferent arteriole in a process called hyaline arteriosclerosis

Question 16

hyaline arteriosclerosis causes

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narrowing and obstruction making it difficult for blood to leave the glomerulus which increase the pressure in the glomerulus resulting in the dilation of the afferent arteriole

Question 17

dilation of the afferent arteriole results in

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more blood entering the glomerulus and increases the pressure even more

Question 18

the increased pressure within the glomerulus causes

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an increase in the glomerular filtration rate (the blood filtered through the glomerulus in one minute)

Question 19

the increased glomerular filtration rate

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is the first step in diabetic nephropathy and is called HYPERFILTRATION

Question 20

in response to the hyper filtration the

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supporting messangial cells secrete more structural matrix which expands the size of the glomerulus

Question 21

the expansion in the size of the glomerulus can result in the

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formation of nodules called KIMMELSTEIN- WILSON NODULES

Question 22

thickening of the basement membrane increases its

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permeability allowing proteins which would otherwise be filtered out to pass through into the filtrate because the filtration slits of the podocyte foot processes have increased in size

Question 23

eventually

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all these changes damage the glomerulus so much that it is no longer able to filter blood properly and the glomerulus filtration rate decreases

Question 24

why is diabetic nephropathy so dangerous

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because during the hyper filtration stage it is silent and only causes symptoms when it has caused end stage renal failure where there is a massive reduction in the glomeruli filtration rate

Question 25

whats paramount in monitoring diabetes

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urinalysis

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microalbunaemia

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30-300mg of albumin excreted in one day indicates that diabetic enphropathy has begun

Question 27

macroalbunaemia

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greater than 300mg of albumin ecreteted in one day indicates that the diabetic nephropathy is well established

Question 28

diabetic nephropathy

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is a progressive complication which can be significantly slowed down but never reversed or completely stopped

Question 29

what is essential in the management of diabetic nephropathy

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managing hypertension and hyperglycaemia

Question 30

management of hypertension in anyone with diabetes

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ACE INHIBITORS because not only does it control the hypertension but it also reduces the constriction of the efferent arteriole

Question 31

if ACE inhibitor are contra-indicated

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then use an angiotensin receptor blocker

Question 32

consequences of diabetic nephropathy

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• development of hypertension

- accelerated vascular disease

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if untreated diabetic nephropathy causes

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a reduction in the glomerular filtration rate of 1ml/min/month

Question 34

all patients over the age of

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12 should be screened for diabetic nephropathy using urinary albumin creatinine ratio (urine ACR)

Question 35

microalbunaemia values

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urine ACR for males: 2.5-25 for females 3.5-35

24hour alumni levels: 30-300mg

Question 36

macroalbunaemia values

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urine ACR greater than 25 for males greater than 35 for females
24hour albumin levels: greater than 300mg

Question 37

blood pressure should be maintained below

Answer 37

130/80mmHg