Microvascular complications Flashcards
What are the sites of microvascular complications?
Retinal arteries Glomerular arteries (kidneys) Vasa nevorum (tiny blood vessels that supply the nerves)
What can make the microvascular complications worse?
Hyperglyacemia
Hypertension
Genetics
Hyperglycaemic memory
Tissue damage through originally reversible and later irreversible alterations in proteins
What level of HbA1C is abrnomal?
6.5 = diabetes
Draw a diagram of what you would see if you looked through an opthalmoscope
See diagram - Optic disc located nasally. Fovea (Macula) site where colour vision is involved.
What background changes in diabetic retinopathy occur?
Hard exudates (cheese colour, lipid) Microaneurysms (dots) Blot haemorrhages
You can see all of these through an opthalmoscope
Describe what would identify pre-proliferative diabetic retinopathy?
Cotton wool spots also called soft exudates
Represent retinal ischaemia
What is proliferative retinopathy?
Visible new vessels
On the disk or elsewhere in retina (macula) - causes vision loss
Define maculopathy
Same disease as background retinopathy, but happens to be near the macula.
There are hard exudates near the macula which can threatens direct vision
How do you manage diabetic retinopathy?
Background retinopathy:
- improve blood glucose control
- Warn patient to go into retinal screening programme of if they have problems with their vision they must go to their GP to have a vessel screen
Pre-proliferative retinopathy
- Suggests general ischaemia
- if left alone the, new vessels will grow (develops into proliferative retinopathy)
- Treat with pan retinal photocoagulation
Proliferative retinopathy
- Treat with pan retinal photocoagulation
Maculopathy
- Only problem around macula = grid of photocoagulation NOT pan retinal photocoagulation
Signs and clinical features of diabetic nephropathy
Hypertension
Progressively increasing proteinuria - Albumin production in the urine
Progressively deteriorating kidney function - Deranges renal function - to test this measure the level of serum creatinine in the blood to estimate GFR. Higher GFR is better.
Classic histological features
What are the histological glomerular changes in patients with diabetic nephropathy?
Mesangial expansion
Basement membrane thickening
Glomerulosclerosis
What are the strategies for intervention of nephropathy?
Diabetic control - control glucose. The lower the HbA1c the lower the risk of microvascular complications
Blood pressure control - Control of blood pressure will slow down the deterioration in kidney function
Inhibition of the activity of RAS system - ACE inhibitors reduce the rate of decline of creatinine thus reducing the rate of deterioration of kidney function
Stopping smoking
How does angiotensin II contribute to the negative effects of diabetic retinopathy?
See slides - the changes make endothelial cells more rigid.
What are the small vessels supplying the nerves called?
Vasa nevorum - neuropathy results when these get blocked. High glucose levels causes inflammation
What are the types of diabetic neuropathy?
Peripheral polyneuropathy Mononeuropathy Mononeuritis complex - random combination of peripheral nerve lesions Radiculopathy Autonomic neuropathy Diabetic amyotrophy
Describe peripheral neuropathy?
Longest nerves supply feet
There is a loss of sensation
More common in tall people and people with poor glucose control
Danger is that patients will not sense an injury to the foot (stepping on a nail, leaving it in until a severe infection occurs)
What are the clinical signs of patients coming in with peripheral neuropathy?
Loss of ankle jerks
Loss of vibration sense (using tuning fork)
Multiple fractures on foot X-ray (Charcot’s joint). This occurs because patients can’t sense whether they are putting more pressure one side of the foot or the other side.
Describe mononeuropathy
One nerve involved:
- Usually sudden motor loss
- Wrist drop, foot drop
- Cranial nerve palsy
- Double vision due to 3rd nerve palsy
What happens to the eye when you have third nerve palsy?
Eye is usually down and out. (VI pulls out, IV pulls down)
Pupil does respond to light. When the pupil is dilated (emergency) tumour or haemorrhage compressing the parasympathetic fibres.
Define radiculopathy?
Pain over spinal nerves, usually affecting dermatome on the abdomen or chest wall
Define of autonomic neuropathy?
Loss of sympathetic and parasympathetic nerves to GI tract, bladder and CVS.
What are the symptoms of autonomic neuropathy?
GI tract:
- difficulty swallowing
- delayed gastric emptying
- constipation / nocturnal diarrhoea
- bladder dysfunction
CVS:
- Postural hypotension
- Cardiac autonomic problems - sudden cardiac test
How can you test for autonomic neuropathy?
Measure changes in HR in response to Valsalve manoevre (blow into the syringe, creates a pressure, normally there is then a change in HR.)
This can be measured by ECG and compare R-R intervals.
