Unit 7 - Diabetes Flashcards
What are the criteria for diagnosing diabetes in an asymptomatic patient?
- Two random finger prick of >11.1 mmol/l
- Two fasting glucose of >7mmol (normal <6.1)
What are the criteria for diagnosing diabetes in a symptomatic patient?
- Random finger prick test of >11.1
- Single fasting glucose test of > 7mmol (normal 6.1)
- Glucose tolerance test of greater than 11.1 (2 hours after glucose)
- HbA1c > 48mmol/mol
What are the symptoms of diabetes?
- Weight loss
- Tiredness
- Thirst
- Polyurea
- Nocturia
- Genital itching/thrush
- Poor wound healing
- Blurred vision
What % of diabetes is type 2?
>85% (Type 1 5-10%)
What other causes of diabetes are there?
- Genetic defects in pancreatic b cell function
- Genetic defect in insulin action
- Disease of the exocrine pancrease e.g. pancreatitis, cystic fibrosis
- Endocrinopathies e.g. Cushing’s, acromegaly
- Drug induced e.g. steroid, atypical antipsychotics
- Gestational diabetes
What is the incidence of diabetes in adults worldwide?
1 in 11
How much more likely are you to get type 2 diabetes if you are south Asian or Caribean?
4-6X
What is the pathogenesis of type 1 diabetes?
Autoimmune cells attack the B-cells in the islets of Langherans.
What is the pathogenesis of type 2 diabetes?
B-cell dysfunction, failure of the B-cell to adapt to insulin resistance
What are the risk factors for type 2 diabetes?
- Obesity
- Diet
- Sedentray lifestyle
- Genetic predisposition
- Glucotoxicity
What are the two major types of diabetic complications?
- Microvascular
- Macrovascular
What are the major macrovascular complications of diabetes?
- Coronary artery disease
- Cerebrovascular disease
- Peripheral arterial disease
What are the major microvascular complications in diabetes?
- Retinpathy
- Nephropahty
- Neuropathy
What is the incidence of nephropathy in type1 and 2 diabetics?
20-40%
What happens to insulin requirements with nephropathy and why?
Insulin requirements go down as kidneys clear insulin so if they’re packing up there is more insulin floating around.
How soon after type 1 diagnosis should a patient be seen for retinal screening?
less than 3 months
What is the management of type2 diabetes with drugs?
Metformin first then try:
- DPP4
- Glitazones
- Suphonylureas
What are the symptoms of hypoglycaemia?
Autonmic:
- Tremor
- Sweating
- Palpitations
Neurglycopenic
- Confusion
- Drowsiness
- Slurring of speech
General malaise
- Headache
- Nausea
What is the general treatment of hyperglycaemia?
Make patient drink 2-3 litres of fluid over 24 hours to prevent dehydration.
What is the prevalence of blindness in type 1 and type 2 diabetics (not all attributable to DR)?
- Type 1 = 3.6%
- Type 2 = 1.6%
What % of blindness is attributable to DR in type 1 and type 2?
Type 1 = 86%
Type 2 = 33%
What is the pathogenesis of DR?
Exposure to glucose = loss of pericytes = basement membrane thickening = breakdown of endothelial barrier function and compromise of capillary lumen
What biochemical abnormalities have been correlated with prevalence and severity of DR?
- Increased platelet adhesiveness
- Increased erythrocyte aggregation
- Abnormal serum lipids
- Abnormal levels of growth hormones
- Upregulation of VEGF
- Abrnormalities in serum and whole blood viscosity
- Defective fibrinolysis
What are the modifiable risk factors in the development of DR?
- Glycaemic control
- BP
- Lipid levels
- Smoking
- Pregnancy
What are the non-modifiable risk factors in DR?
- Genetic factor (accounts to 25-50% of risk)
- Gender
- Duration of diabetes
- Renal impairment
- Carotid arterial disease
What effects does diabetes have on the vasculature in retinopathy?
Pericyte and endothelial cell death = breakdown of BRB
What effects does diabetes have on the glia and microglia in retinopathy?
Glia = altered contact with vessels results in a release of inflammatory mediators and iimpaired glutamate metabolism
Microglia = Increase in phagocytes leads to increased inflammation and more cell death.
What ocular tests should be conducted on a DR patient?
- V/A
- Colour vision, severity of defect = severity of DR
- Colour photos
- Anterior segment; check for cataract, glaucoma and NVI
- FFA
- OCT
Where are CWS most commonly found and why?
Nasally as nerve fibre layer is thicker there.
What are the clinical features of non-proliferative DR?
- MA’s
- Blot haems
- CWS
- IRMA
- Venous beeding
What is an MA in DR?
Isolated capillary occlusions causing nearby non-occluded capillaries to form saccular swellings.
What are blot haems and why?
- Deep retina infarcts
- Occur when clusters of capillaries occlude to form intraretinal haems
What are IRMA?
Shunt vessels. Either new vessel growth within the retina or remodeling of pre-existing vessels through endothelial proliferation.
How do IRMA differ from NV?
IRMA are slightly larger in caliber and are always contained to the intraretinal layers. NV are finer and delicate . NV leak on FFA whereas IRMA’s don’t
What is venous beeding caused by?
Endothelial cell proliferation.
