Microvascular complications of diabetes mellitus Flashcards
What are the sites of microvascular complications
Retinal arteries
Glomerular arterioles
Vasa nervorum (vessels that supply nerves)
What are the risk factors for microvascular disease
Severity of hyperglycaemia
Hypertension
genetic
Hyperglycaemic memory
Are microvascular complications reversible
Tissue damage through originally reversible
Later irreversible alterations in proteins
What are the mechanisms of glucose damage
Polyol pathway
AGEs
Protein kinase C
Hexosamine
Explain how hyperglycaemia and hyperlipidaemia lead to the complications of diabetes
- Hypoxia, oxidative stress, age-range
- Inflammatory signalling cascades
- Local activation of pro-inflammatory cytokines
- Inflammation
Describe microvascular complications (key facts)
Microvascular -> more likely to get microvascular disease
Increase in morbidity
Increased risk of microvascular if HbA1C is increased
What is hyperglycaemic memory
Even if you’ve had poor glycaemic control for a short period of time, it will cause an increased risk of microvascular complications compared to someone who has been well controlled throughout
What are the types of retinopathy
Background retinopathy
Pre-proliferative retinopathy
Proliferative retinopathy
Maculopathy
What can be seen in a fundoscopic view
Optic disc at the nasal part of the eye
Macula (fovea) laterally
What are the features of background retinopathy
Hard exudates (leakage of lipid) Microaneurysms (red dots, rupture...) Blot haemorrhages
What is the management for background retinopathy
Improve blood glucose control
Warn patient that warning signs are present
What are the features of pre-proliferative retinopathy
Cotton wool spots (soft exudates)
Represent retinal ischaemia
Describe the management for pre-proliferative and proliferative retinopathy
Pan-retinal photocoagulation (laser the retina to stop vessels from bleeding + new vessels growing)
What are the features of proliferative retinopathy
From untreated pre-proliferative retinopathy
New vessels on optic disc or elsewhere (response to retinal ischaemia, new vessels are more fragile and can bleed anytime, if form in region of macula- can affect acuity and colour vision)
What are the features of maculopathy
Hard exudates near the macula
Same disease as background, but is near macula
This can threaten direct vision (+ acuity and colour)
What is the management for maculopathy
Grid-photocoagulation
What are the clinical features of diabetic nephropathy
Hypertension
Progressively increasing proteinuria
Progressively deteriorating kidney function
Classic histological features
What are the histological features of glomerular changes in diabetic nephropathy
Less flexible and harder:
Mesangial expansion
Basement membrane thickening
Glomerulosclerosis
What are the strategies for diabetic nephropathy intervention
Diabetic control
Blood pressure control
Inhibition of the activity of RAS system (ACE inhibitors reduce rate of creatinine increase (↑creatinine=↓kidney function)
Stopping Smoking
What are the types of diabetic neuropathy
Peripheral polyneuropathy Mononeuropathy Mononeuritis multiplex Radiculopathy Autonomic neuropathy Diabetic amyotrophy
Describe peripheral neuropathy and its risk factors
Sensory loss
Test with monofilament (foot prick)
Danger= patient wont sense an injury on foot- fractures, Charcot foot, ulcer.
Tall patients (Longer nerves to the feet, loss of sensation) Patients with poor glucose control
What are the clinical features of peripheral neuropathy
Loss of ankle jerks
loss of vibration sense (using tuning fork)
multiple fractures on foot X-ray (Charcot’s joint)
Describe mononeuropathy
Usually sudden motor loss
wrist drop, foot drop
Cranial nerve palsy:
double vision due to 3rd nerve palsy
Describe the third nerve palsy
Eye is down and out
Pupil responds to light
The parasympathetic fibres are on the outside so do not easily lose blood supply
Aneurysm -> press on parasympathetic fibres -> fixed dilated pupil
