Microvascular complications

Question 1

What are the sites of microvascular complications?

Answer 1

Retinal arteries
Glomerular arteries (kidneys)
Vasa nevorum (tiny blood vessels that supply the nerves)

Question 2

What can make the microvascular complications worse?

Answer 2

Hyperglyacemia
Hypertension

Genetics
Hyperglycaemic memory

Tissue damage through originally reversible and later irreversible alterations in proteins

Question 3

What level of HbA1C is abrnomal?

Answer 3

6.5 = diabetes

Question 4

Draw a diagram of what you would see if you looked through an opthalmoscope

Answer 4

See diagram - Optic disc located nasally. Fovea (Macula) site where colour vision is involved.

Question 5

What background changes in diabetic retinopathy occur?

Answer 5

Hard exudates (cheese colour, lipid)
Microaneurysms (dots)
Blot haemorrhages 

You can see all of these through an opthalmoscope

Question 6

Describe what would identify pre-proliferative diabetic retinopathy?

Answer 6

Cotton wool spots also called soft exudates

Represent retinal ischaemia

Question 7

What is proliferative retinopathy?

Answer 7

Visible new vessels

On the disk or elsewhere in retina (macula) - causes vision loss

Question 8

Define maculopathy

Answer 8

Same disease as background retinopathy, but happens to be near the macula.
There are hard exudates near the macula which can threatens direct vision

Question 9

How do you manage diabetic retinopathy?

Answer 9

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

Question 10

Signs and clinical features of diabetic nephropathy

Answer 10

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

Question 11

What are the histological glomerular changes in patients with diabetic nephropathy?

Answer 11

Mesangial expansion
Basement membrane thickening
Glomerulosclerosis

Question 12

What are the strategies for intervention of nephropathy?

Answer 12

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

Question 13

How does angiotensin II contribute to the negative effects of diabetic retinopathy?

Answer 13

See slides - the changes make endothelial cells more rigid.

Question 14

What are the small vessels supplying the nerves called?

Answer 14

Vasa nevorum - neuropathy results when these get blocked. High glucose levels causes inflammation

Question 15

What are the types of diabetic neuropathy?

Answer 15

Peripheral polyneuropathy
Mononeuropathy
Mononeuritis complex - random combination of peripheral nerve lesions
Radiculopathy
Autonomic neuropathy
Diabetic amyotrophy

Question 16

Describe peripheral neuropathy?

Answer 16

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)

Question 17

What are the clinical signs of patients coming in with peripheral neuropathy?

Answer 17

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.

Question 18

Describe mononeuropathy

Answer 18

One nerve involved:

• Usually sudden motor loss
• Wrist drop, foot drop
• Cranial nerve palsy
• Double vision due to 3rd nerve palsy

Question 19

What happens to the eye when you have third nerve palsy?

Answer 19

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.

Question 20

Define radiculopathy?

Answer 20

Pain over spinal nerves, usually affecting dermatome on the abdomen or chest wall

Question 21

Define of autonomic neuropathy?

Answer 21

Loss of sympathetic and parasympathetic nerves to GI tract, bladder and CVS.

Question 22

What are the symptoms of autonomic neuropathy?

Answer 22

GI tract:

• difficulty swallowing
• delayed gastric emptying
• constipation / nocturnal diarrhoea
• bladder dysfunction

CVS:

• Postural hypotension
• Cardiac autonomic problems - sudden cardiac test

Question 23

How can you test for autonomic neuropathy?

Answer 23

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.