Microvascular Complications Flashcards
What sites are included in microvascular complications?
- Renal arteries
- leads to diabetic retinopathy - Glomerular arterioles - kidneys
- leads to nephropathy - Vasa nervorum - tiny blood vessels that supply nerves
- leads to neuropathy
What can microvascular complications come about/ be exacerbated by?
o Severity of hyperglycaemia
- the worse it is, the worse the damage
- the higher the HbA1C, the worse the microvascular complication
o Hypertension
o Genetic
o Hyperglycaemic memory
- poor diabetes control, even for a brief period, will give an increased of microvascular complication (compared to someone that has had good control throughout)
o Tissue damage
- originally reversible BUT later irreversible alterations in proteins
Possible mechanisms of glucose damage?
o Polyol pathway
o AGEs
o Protein Kinase C
o Hexosamine
Diabetic Retinopathy?
Damage to renal arteries!
Main cause of visual loss in people with diabetes and the main cause of blindness in people of working age
Normal retina?
Optic disc - at the nasal part of eye
Macula - more lateral (i.e. central)
ONENOTE!
What is the function of the macula?
Involved in
o colour vision
o acuity (clarity of vision)
4 different types of Diabetic Retinopathy?
- Background diabetic retinopathy
- Pre-proliferative diabetic retinopathy
- Proliferative retinopathy
- Maculopathy
Background Diabetic Retinopathy?
o Hard exudates
- appear cheesy yellow spaces in retina
- caused by leakage of lipid content
o Microaneurysms
- small blood vessel bulge
o Blot haemorrhages
- blots of blood that are ruptured microaneurysms
ONENOTE!!
Pre-proliferative diabetic retinopathy?
o Cotton wool spots - SOFT EXUDATES
- these show retinal ischaemia
ONENOTE!!
Proliferative retinopathy?
o Visible NEW vessels
- form as a response to the retinal ischaemia
- generally more FRAGILE so can bleed at any time
- can form on optical disc or elsewhere
If vessels form in region of macula, can cause problems w. acuity & colour vision
Maculopathy?
Same as ‘Background DR’ BUT nearer to macula
o Hard exudates NEAR MACULA
- can threaten DIRECT VISION!
How can Background DR be managed?
o Improve control of blood glucose
o Warn patient that warning signs are present
How can Pre-proliferative DR be managed?
Suggests general ischaemia SO need to stop it from progressing to proliferative DR! Need:
o Pan-retinal photocoagulation
- laser to retina to stop vessels from bleeding
How can Proliferative DR be managed?
ALSO needs pan-retinal photocoagulation
dark spots shows its been used - ONENOTE!!
How can Maculopathy be managed?
Only have problem around macula so only need a GRID of photocoagulation!
i.e. grid-retinal photocoagulation
NOT pan-retinal photocoagulation
Diabetic Nephropathy?
Glomerular arteries in the kidneys
Features of diabetic nephropathy?
o Hypertension
o Progressively increasing proteinuria
o Progressively deteriorating kidney function
o Classical histological features
What can diabetes increase the risk of?
Having diabetes & CKD can increase risk of CV events occurring
You can see classic histological features for diabetic nephropathy - what are they?
- Glomerular changes
o mesangial expansion
o BM thickening
- both are due to overproduction of matrix
o glomerulosclerosis (hardening of capillaries)
- Vascular
- Tubulointestinal
Relationship between retinopathy, CKD and diabetes?
If there is NO retinopathy
ANY CKD can NOT be due to diabetes (they come together)
Epidemiology of T1 & T2DM in terms of CKD?
T1DM
o 20-40% of patient have CKD after 30-40years
T2DM o probably equivalent BUT difficult to determine due to - age of development of disease - racial factors - age at presentation - loss due to CV morbidity
Clinical features of diabetic nephropathy?
o Progressive proteinuria
- hallmark for CKD
- Normal range = <30mg/24hrs
- Nephrotic range = >3000mg/24hrs
o Increased BP
- glomerulus becomes less flexible & harder
- absorption of nutrients can change - more pressure going through kidneys
- changes BP control
o Deranged renal function
- GFR decreases
Intervention strategies for diabetic nephropathy?
- Diabetic control
o the lower the HbA1C, the lower the microvascular complications - BP control
o will slow down the deterioration of kidnet function - Inhibition of RAS
o ACE inhibitors reduce rate of decline of creatinine and thus kidney function
o ANGII involved in many growth & inflammatory pathways so inhibiting it is good - STOP SMOKING
Why can ANGII be detrimental in diabetic nephropathy?
o Stimulates pathways resulting in overproduction of matrix
o Cause constriction of efferent arterioles
- increasing transglomerular capillary pressure
o Lead to increasing rigidity of endothelial cells (onenote!!)
