Block 1: diabetes Flashcards
Diabetes symptoms
Polyuria, fatigue, blurred vision, polydipsia, weight loss, nocturia
Diagnosing diabetes if asymptomatic
- fasting glucose greater than or equal to7.0 mmol/l
- random glucose greater than or equal to11.1 mmol/l(or after 75g oral glucose tolerance test)
- If patient is asymptomatic needs two blood results to confirm
Using HbA1c to diagnose diabetes
- When greater than or equal to 48mmol/mol
- If less does not exclude diabetes
- In asymptomatic patient test must be repeated to confirm diagnosis
- Misleading HbA1c can be caused by high red cell turnover: haemoglobinopathies, haemolytic anaemia, iron deficient anaemia, gestational diabetes
Prediabetes
- HbA1c is 42-47
- Fasting glucose is 6.1-6.9
Impaired fasting glucose and impaired glucose tolerance
- Fasting glucose between 6.1-7 is impaired fasting glucose (IFG)
- Impaired glucose tolerance (IGT) is a fasting plasma glucose less than 7 and a OGTT between 7.8 and 11.1
- Patients with IFG should be offered an OGTT to rule out diabetes of IGT
- In IFG OGTT is <7.8
- In IGT and IGT HBa1c is 42-47
- Incidence increases with age
General principles of medication in T2D
You can titrate up metformin and encourage lifestyle changes to aim for a HbA1c of 48 mmol/mol (6.5%), but should only add a second drug if the HbA1c rises to 58 mmol/mol (7.5%)
Dietary advice T2D
- Reduce saturated fats but include low fat dairy products and oily fish
- Encourage high fibre, low-glycaemic index carbohydrates
- Initial target weight for an overweight person is 5-10%
HbA1c targets
- Should be checked every 3-6 months till stable, then 6 monthly
- Can be relaxed for elderly
- If patient wants to try lifestyle treatment first, HbA1c target is 48
- If patient on metformin target is 48
- If 6 months after starting metformin HbA1c has risen to 51, to increase metformin from 500mg bd to 500mg td and reinforce lifestyle
- If already on one drug but HbA1c has risen to 58 then target is 53
Initial drug therapy for T2D
- If high risk of CVD, established CVD or chronic heart failure then prescribe metformin and once established an SGLT-2 inhibitor
- If no cardiovascular risk prescribe metformin
- Metformin should be titrated slowly to reduce gastro side effects
- If metformin not tolerated prescribe modified release
- If cardiovascular risk increases an SGLT-2 inhibitor can be prescribed at any time
What to do if metformin is contraindicated
- If risk of CVD/Heart failure: SGLT-2 (empagliflozin) montherapy
- If no risk prescribe an DPP-4 inhibitor (Sitagliptin) or Pioglitazone or Sulfonylurea. SGLT-2 can be used occasionaly
Further drug therapy if HbA1c targets aren’t met
- If HbA1c has risen to 58 then further treatment is indicated
- Add one of: DPP-4 inhibitor (Sitagliptin), Pioglitazone, Sulfonylurea (Gliclazide), SGLT-2 inhibitor (empagliflozin) i.e. Metformin + X
- Add another drug from the same list i.e. Metformin + x + z. OR start insulin based treatment
- Further therapy= if triple therapy is not effective switch one of the drugs for a GLP-1 mimetic if BMI >35 or insulin has occupational implications. GLP-1 mimetic is only added to insulin in specialist care. Only continue if there is a reduction of 11 mmol HbA1c and weight loss of 3% in 6 months
Starting insulin
- Metformin should be considered
- Start with human NPH insulin (isophane, intermediate acting) taken at bed time or twice daily
Microvascular complications of diabetes
- Diabetic retinopathy: damage to retinal vasculature leading to microaneurysms, haemorrhage and neovascularisation. Treatment is laser therapy and anti-VEGF injections
- Diabetic Nephropathy: common cause of CKD. Characterised by albuminuria, declining GFR and renal failure. Management is blood glucose and pressure control, use of ACEI’s or ARBs and dietary modification
- Diabetic Neuropathy: includes peripheral neuropathy, autonomic neuropathy, and focal neuropathies. Peripheral neuropathy presents with pain, numbness and tingling in the extremities increasing the risk of foot ulcers and amputation. Autonomic neuropathy affects the autonomic nervous system leading to GI, cardiovascular and GU dysfunction. Focal neuropathies affects specific nerves resulting in localised weakness or pain. Management is tight glycaemic control, pain management and appropriate foot care
Diabetes: Macrovascular complications
- Coronary artery disease: management is risk factor modification of blood glucose, lipid and blood pressure control, using antiplatelet therapy and revascularisation procedures
- Cerebrovascular disease: diabetic patients are at increased risk of stroke and TIA. Stroke prevention includes blood glucose, lipid and blood pressure control, antiplatelt therapy and lifestyle modification such as smoking cessation, exercise and weight management
- Peripheral artery disease: can cause intermittent claudication, critical limb ischaemia and amputation. Management includes risk factor modication, exercise therapy, revascularisation procedures when needed and diligent food care to prevent ulcers and infection
Other diabetes complications
- Diabetic foot: due to combination of neuropathy, PAD and impaired wound healing. Can result in foot ulcers, infections and ultimately amputations
- Infections: T2DM patients are more susceptible to infections due to immune dysfunction, impaired wound healing, and increased colonization of pathogens. Common infections include urinary tract infections, skin and soft tissue infections, and respiratory infections.
- Hyperglycaemic emergencies: DKA is rare in T2DM but may occur in cases of severe insulin deficiency. Hyperosmolar hyperglycemic state (HHS) is more common in T2DM patients and is characterized by severe hyperglycemia, hyperosmolarity, and dehydration. Both conditions require prompt recognition and management with fluid resuscitation, insulin therapy, and electrolyte replacement.
Hypoglycaemia defenition
Occurs when glucose concentrations fall below 3.3mmol. Occurs more commonly in diabetics
Diabetes and Hypoglycaemia
- Hypoglycaemia is caused by excess insulin by either taking too much or not eating enough after administering insulin
- Sulfonylureas i.e. gliclazide increase secretions of insulin from beta cells and cause Hypoglycaemia
- More likely to occur in diabetics with a viral illness, have drunk alcohol, exercised more than usual or started/changed medication
Non diabetic causes of hypoglycaemia
- Iatrogenic: indomethacin, pentamidine, quinine, sulfonamide, IGF-1 and lithium.
- Alcohol consumption due to its inhibitory effect on gluconeogenesis and glycogenolysis.
- Rare causes: Hypopituitarism and Addisons disease
Hypoglycaemia physiology
- Low blood glucose increases production of glucagon from alpha cells and reduced production of insulin from the beta cells of the pancreas. Causes liver gluconeogenesis and glycogenolysis
- Reduced blood glucose increases adrenaline secretion from the adrenal medulla
- Reduced blood glucose stimulates secretion of GH from the pituitary, ACTH is also secreted from the pituitary stimulation cortisol secretion from the adrenal cortex
- All this increases blood glucose
Symptoms of hypoglycaemia
- Autonomic symptoms (<3.3): release of glucagon and adrenaline causes sweating, shaking, hunger, anxiety and nausea
- Neuroglycopenic symptoms (<2.8); due to inadequate glucose supply to the brain causes weakness, vision change, confusion and dizziness
- Severe and uncommon symptoms: convulsion and coma