Diabetes Flashcards
What is diabetes?
An elevation of blood glucose above a diagnostic threshold
How is the diagnostic threshold for diabetes decided?
The blood glucose level at which a person’s risk pf developing retinopathy increases substantially
What are the different criteria for diagnosing diabetes?
Random or 2 hour glucose >11.1
OR a fasting glucose of >7 mmol/L
OR an HbA1c >48 mmol/mol
Needs confirmatory test if patient is asymptomatic
How is the diagnostic criteria for gestational diabetes different from other types of diabetes?
The threshold is lower as it is based on risk to the foetus, not risk of developing retinopathy
How is C-peptide useful for monitoring diabetes?
It is a measure of insulin secretion
If a patient has had an injection of insulin, measuring insulin won’t be representative of the inulin secretion so C-peptide can be measured as it is secreted along with insulin so gives indication of insulin secretion
How can types of diabetes be classified?
Disorders of beta cells (insulin secretion)
Disorders of insulin action
Mixed - T2DM
What are some disorders of insulin secretion?
T1DM
MODY (Maturity Onset Diabetes of the Young)
Pancreatic disease
What are some disorders of insulin action?
Donohue syndrome
NAFLD
Cushing’s
Steroid induced
What is type 1 diabetes?
Autoimmune destruction of the pancreatic beta cells resulting in beta cell deficiency
What is type 2 diabetes?
Insulin resistance and insulin deficiency
Kind of a diagnosis of exclusion - not type 1 and not any other cause
What are the differences between type 1 and 2 diabetes?
T1 usual onset is young and T2 is usually middle age and elderly (but both can occur in any age)
T1 not associated with being overweight, where T2 is (but not always)
T1 is autoimmune, T2 is not
T1 requires insulin treatment, T2 doesn’t usually
What are the symptoms of high blood glucose?
Polyuria Thirst and polydipsia Blurred vision Genital thrush Fatigue Weight loss
What are the symptoms of retinopathy?
Loss of vision
Retinal bleed
Retinal changes found by optician
What are the complications of diabetes?
Retinopathy Neuropathy Nephropathy High blood pressure Dyslipidaemia MI/ACS Stroke Peripheral vascular disease Cognitive dysfunction/dementia
What is HbA1c and why is it useful?
Glycated haemoglobin
Haemoglobin exposed to glucose becomes glycated
Red blood cells survive for about 90 days so HbA1c gives measure of glucose exposure over the last 90 days
What is HbA1c now measured in, and what did it used to be measured in, and how do you convert?
Now - mmol/mol
Old - %
7%=53mmol/mol
+1% = +11mmol/mol
How is HbA1c used in clinical practice?
To monitor diabetes
What is the aim for HbA1c level?
<53mmol/mol (7%)
What is the treatment algorithm for T2 diabetes?
Diagnosis Therapeutic lifestyle change (can go into remission) Monotherapy Combination therapy without insulin Combination therapy with insulin
What is the main dietary advice for patients diagnosed with T2 diabetes?
Normal intake of unrefined carbohydrates, reduction of refined sugar intake
Reduce fat intake
Increase fruit and veg
Reduce salt
What are the main drugs used in the treatment of T2DM?
Metformin Sulphonylureas Thiazolidinediones (TZDs) Incretin drugs (DPP4 inhibitors and GLP-1 receptor inhibitors) SGLT2i
What screening is done for diabetes complications?
Digital retinal screening
Foot risk assessment
Urine albumin:creatinine ratio, creatinine levels
How does HbA1c affect the rate of complications?
As HbA1c increases, risk of complications increases
An 11mmol/mol reduction in HbA1c means 37% decrease in complication risk
How does hyperglycaemia result in complications?
Glucose is not being completely oxidised by glycolysis and mitochondrial metabolism (TCA)
Glucose is therefore broken down by alternative pathways.
These alternate pathways cause osmotic damage, inflammation, fibrosis and increases reactive oxygen species
This causes damage and complications
What are the main microvascular complications?
Retinopathy
Nephopathy
Neuropathy
What eye pathologies do people with diabetes get?
Diabetic retinopathy Diabetic macular oedema Cataracts Glaucoma Acute hyperglycaemia (blurred vision)
What are cataracts?
Clouding of the lens (earlier complication)
What is glaucoma?
Increase in fluid pressure in the eye leading to optic nerve damage
What are the foeva and macula?
The site where most of the rods and cones are concentrated
What is referrable maculopathy?
When changes occur 1 disc diameter around the fovea
What is observable maculopathy?
When changes occur between 1 and 2 disc diameters from the fovea
What are the stages of retinopathy?
- Mild non-proliferative (background) retinopathy
- Moderate non-proliferative retinopathy
- Severe non-proliferative
- Proliferative
What are microaneurysms?
Tiny widenings of arteries
Pretty benign - only significant if growing
A precursor to more severe disease
What are haemorrhages, and what are the types?
Micro-bleeds
Dot haemorrhages - very small ones
Blot haemorrhages - larger
Flame haemorrhages - flame shaped
What are hard exudates?
Lipid deposits
What are cotton wool spots?
Areas of ischaemia
What are Intra-Retinal Microvascular Abnormalities (IRMA)?
Development of microvascular changes
Why is new vessel formation significant?
Worrying - can be a sign of imminent haemorrhage
What is vitreous haemorrhage, what does it cause and what is the management?
Bleeding in the eye
Sudden change in vision
Requires surgery
What is the treatment for retinopathy?
Laser - pan retinal photocoagulation
What is pan retinal photocoagulation?
Zapping peripheral parts of the retina with a laser. This kills cells so reduces the oxygen requirement of retina, reducing the ischaemia that drives retinopathy
What is the side effect of pan retinal photocoagulation?
Lots will cause you to start to lose peripheral vision
What is the treatment for vitreal haemorrhage?
Vitrectomy
What is the treatment for diabetic macular oedema?
Optical coherence tomography to assess
Intravitreal anti-VEGF to treat
What is diabetic nephropathy?
Progressive kidney disease caused by damage to the capillaries in the glomeruli of the kidneys
Characterised by proteinuria and diffuse scarring of the glomeruli
What are complications of diabetic nephropathy?
Development of hypertension
Decline in renal function
Accelerated vascular disease
What is the albumin:creatine ratio (ACR) for normal, microalbuminaemia, and proteinuria?
Normal: <3.5 for females, <2.5 for men
Microalbuminaemia: <30
Proteinuria: >30
What is the protein:creatine ratio (PCR) for microalbuninaemia and proteinuria?
Microalbuminaemia: <50
Proteinuria: >50
What are examples of things that can give a false positive of microalbuminaemia?
Mentruation Vaginal discharge UTI Pregnancy Other illness Non-diabetic renal disease
How many tests do you need to determine microalbuminaemia?
3 - at least 2 positive
What is the difference between incipient and overt neuropathy?
Defined on the basis of urine protein
Normal ACR to 30 is incipient, >30 is overt
How is nephropathy screened for?
Urinary albumin and serum creatine are measured at diagnosis and at regular intervals
Abnormal result is confirmed by another sample
What is done when microalbuminaemia detected?
Monitor serum creatine Check for retinopathy Investigate other causes of renal pathology Screen for peripheral vascular disease Discourage smoking Tighten glycaemic control Assess fasting lipid profile Screen and treat hypertension aggressively Screen for ischaemic heart disease
What is the first line treatment for nephropathy?
ACE inhibitors or ARBs
What T2DM treatment is effective in proteinuria and kidney disease?
SGLT2 inhibitors
What does diabetic nephropathy lead to?
Chronic kidney disease and end stage kidney disease
What are the types of neuropathy?
Peripheral
Proximal
Autonomic
Focal neuropathy
What is an example of peripheral neuropathy?
Pain/loss of feeling in feet and hands
What is an example of proximal neuropathy?
Pain in the thighs, hips or buttocks leading to weakness in the legs
What is an example of autonomic neuropathy?
Changes in bowel, bladder function, sexual response, sweating, heart rate, blood pressure
What is focal neuropathy?
Sudden weakness in one nerve or a group of nerves causing muscle weakness or pain e.g. carpal tunnel, ulnar mono neuropathy, foot drop, bells palsy, cranial nerve palsy
What are the risk factors for neuropathy?
Increased length of diabetes Poor glycemic control T1DM (more than T2) High cholesterol lipids Smoking Alcohol Inherited traits Mechanical injury
What are symptoms of peripheral neuropathy?
Numbness/insensitivity Ingling/burning Sharp pains or cramps Hyper-sensitivity to touch Loss of balance and coordination
What are the consequences of peripheral neuropathy?
Charcot foot
Painless trauma
Foot ulcer
What is charcot foot?
A destructive inflammatory process in the foot that causes bony destruction and deformity of the foot
Can be precipitated by fractures
What is the natural history of charcot arthropathy?
Active destruction (3 months) Healing phase (4-8 months) Chronic phase (8 months)
What is the presentation of charcot arthropathy?
A hot swollen foot in someone with neuropathy
How is charcot arthropathy distinguished from infection?
MRI
What is the treatment for charcot arthropathy?
Non-weight bearing
Total contact cast or airiest boot
What is the treatment for painful neuropathy?
Amitriptyline, gabapentin
What is diabetic amyotrophy?
Starts with pain in the thighs, hips, buttocks or legs, usually on one side of the body
More common in elderly T2DM
Proximal muscle weakness
What does autonomic neuropathy cause?
Dysfunction of the nerves regulating heart rate and blood pressure
Digestive system - gastric slowing or frequency, gastroparesis, oesophagus nerve damage
Overactive sweat glands
What can mononeuropathy cause?
VI cranial nerve palsy
Carpal tunnel syndrome
