6. Diabetes Flashcards
What are the different types of diabetes people can get?
- Type 1
- Type 2
- Gestational diabetes (mums can aquire during pregnancy)
- MODY (Young)
- LADA (Adults)
What is Type 1 (T1DM) ?
Autoimmune diorder where T helper cells attack the beta cells of the islets of langerhans in the pancreas.
What is Type 2 (T2DM)?
Insulin resistance. There is a genetic basis for susceptibility to T2DM - the trigger is obesity and lack of exercise.
What is the prevalence of DM? And what is it predicted to be by 2040?
In 2015 = 1 in 11 adults
More than 80% was T2DM.
Prediction =
2040 = 1 in 10 adults
Currently = 334 million
What are the complications of diabetes?
Primary pathogenesis chronic hyperglycemia affects first the small organs and then the larger ones.
Small organs being the eyes and kidneys.
Cardiovascular problems.
What are the Macrovascular complications from DM?
- Coronary artery affected =
Angina (chest pains when heart doesn’t recieve enough O2)
Myocardial infarction (heart attack) - Carotid artery =
Stroke
Hemiplegia (paralysis of one side of body) - Iliac/femoral artery occlusion =
pain on walking
Gangrene
What are the Microvascular complications from DM?
- Kidney damage (nephropathy)=
Nearly all such patients also will have retinopathy - Neuropathy (nerve damage) & Ischemia (lack of blood flow to tissue/organ leading to cell death) =
Loss of sensation- Won’t be able to feel contact lenses so more difficult to insert and retrieve.
Injuries go unnoticed- will continue normal activites without noticing injury more prone to infection. - Autonomic neuropathy=
symptoms of sweating, gastric upsets (nausea and diarrhea) - Peripheral neuropathy =
symptoms pain in arms and legs which keeps Px awake.
What are the risk factors for diabetic retinopathy (DR)?
- Having disease for over 5 years
- Poor glycaemic control
- Also having systemic hypertension
- Puberty, pregnancy
- Sudden normoglycaemia (Suddenly going from high/low to normal blood glucose)
- Smoking
What is the statistics of onset for DR for both T1 and T2?
T1:
98% after 25 years
50% will eventually get PDR (proliferative diabetic retinopathy)
T2:
10/20% have retinopathy at diagnosis
60% after 20 years.
What are the complications of diabetic retinopathy (DR)?
- Microangiopathy (damage to small blood vessels)
- Changes to major retinal arteries and veins
- Loss of control of flow through capillaries
- Ischemia - Endothelial cells leak or become blocked.
What are the signs of DR?
- leakage from capillaries into neurosensory retina
- Plasma (Oedema), lipids, red blood cells (dot haemorrhages)
- Non perfusion of capillaries (lack of blood flow to capillaries)
- Ischaemia promotes Vascular endothelial growth factor (New blood vessels grow which will be fragile and more likely to break causing more haemorrhages)
- New blood vessel formation within vitreous
- Pre retinal and optic disc neovascularisation (New blood vessels grow, these vessels need some structure support so retina becomes fibrotic. The blood vessels are fragile and prone to break)
What is NPDR and what are the signs?
Non Proliferative diabetic retinopathy is the early stages of diabetic retinopathy.
Signs:
1. Microaneurysms
2. Dot haemorrhages
3. Retinal oedema (Thickening)
4. Lipid exudates - in circinate distribution (ring like pattern)
5. Cotton wool spots (soft exudates- the nerves die releasing everything within, known as axoplamic transport. White swellings in the inner retina.)
6. Blot haemorrhages
7. Intraretinal microvascular abnormalities
8. Beading and looping of the retinal veins (Beading look like string of sausages) This is the sign that the blood vessel wall is damaged.
9. IRMA
What is PDR and what are the signs?
Proliferative diabetic retinopathy is later stages of diabetic retinopathy.
Signs:
1. Preretinal and optic disc neovascularisation (New blood vessels grow, these vessels need some structure support so retina becomes fibrotic. These fibres pull on retina causing retina detachment. The blood vessels are fragile and prone to break)
2. Vitreous haemorrhage (can occur due to neovascularisation, the fragile blood vessels break)
3. Tractional retinal detachment - linked to point 1
4. Iris neovascularisation (rubeosis iridis)
Where do the signs of DR occur in retinal structures?
1.Nerve fiber layer =
Flame shaped haemorrhages
Cotton wool spots
- Inner nuclear layer =
Dot/blot haemorrhages
Hard exudates - Outer plexiform layer =
Hard exudates
What is IRMA and how to differentiate it from neovascularisation?
Intraretinal microvascular abnormalities. Another sign of DR.
IRMA and neovascularisation both involve abnormal blood vessel growth but differ in characteristics. IRMA is less severe, and less fragile, so do not leak. More burgundy in colour and blurry edges. Not on opitc disc. Seen before neovascularisation- NPDR.
IRMA involves dilated, dropout capillaries within the inner layers of retina, but DO NOT grow out of the retinal surface. Whilst in neovascularisation blood vessels grow out into the vitreous. More severe, more fragile.
Normal retinal capillaries are too small to be resolved using ophthalmoscope. But IRMA dilates the capillaries making them visible.
To differentiate from neovascularisation can use fluorescein anigiography. (Specialised imaging technique.)
