Type 1 & Type 2 Diabetes Mellitus Flashcards
What is type 1 diabetes?
Who does it affect?
What is type 1 diabetes associated with?
What is the genetic susceptibility?
What is the environment influence?
Type 1 diabetes : insulin deficiency due to autoimmune destruction of insulin secreting pancreatic beta cells
Onset: common in adolescent but can affect anyone
Assoc. with other autoimmune disease i.e. coeliac’s, Addison’s and pernicious anaemia.
Genetics: >90% people carry HLA DR3 ± DR4
Environment => most type 1 diabetic don’t have close family hx & only 10% with HLA susceptible gene develop diabetes:
=> maternal factors i.e. gestational infections
=> viral infections i.e. coxsackie B
=> exposure to cow’s milk and deficiency of vitamin D
=> childhood obesity
=> psychological stress
What is type 2 diabetes?
Who does it affect?
What is type 2 diabetes associated with?
What is the genetic susceptibility?
Type 2 diabetes = low insulin secretion ± high insulin resistance
Onset: prevalence higher in asians ; men ; >40yrs but teenagers with type 2 increasing
=> pancreatic beta cell function declines with age so incidence of type 2 diabetes increases with age
Assoc. with obesity, lack of exercise, calorie & alcohol excess
Genetics: >80% concordance in twins => higher genetic susceptibility than type 1 diabetes
What are the symptoms of hyperglycaemia?
Polyuria
Polydipsia
Unexplained weight loss
Visual blurring
Genital thrush
Lethargy
What are the other causes of diabetes?
Steroids ; anti-HIV drugs ; newer anti-psychoticss
Pancreatitis ; pancreatic surgery (>90% pancreas removed) ; trauma ; pancreatic destruction (haemachromatosis, cystic fibrosis) ; pancreatic cancer
Cushing’s disease ; acromegaly ; phaeochromocytoma ; hyperthyroidism ; pregnancy
How do you diagnose diabetes?
i) Symptoms of hyperglycaemia AND raised venous glucose once : Fasting >7mmol/L or Random >11.1mmol/L
OR
ii) Raised venous glucose on 2 separate occasions : Fasting >7mmol/L or Random >11.1mmol/L or glucose tolerance test (OGTT) - 2h value >11.1mmol/L
OR
iii) HbA1c >48mmol/mol => Avoid in pregnancy, children, type 1 DM & haemoglobinopathies
What are the features of type 1 diabetes?
Weight loss
Persistent hyperglycaemia despite diet & medications
Presence of autoantibodies i.e. islet cell antibodies and anti-glutamic acid decarboxylase antibodies
Ketonuria
Differences between type 1 and type 2 diabetes:
Type 1 DM: => Starts before puberty => HLA D3 & D4 linked => Autoimmune beta-cell destruction => Polydipsia, polyuria, weight loss, ketosis
Type 2 DM: => Older patients (usually) => No HLA assoc. => Insulin resistance / beta cells dysfunction => Asymptomatic / complications e.g. MI
*Not all new onset diabetes in older patients = Type 2 DM
=> If ketotic ± poor response to oral hypoglycaemic
=> Patient slim ± has family or self Hx of autoimmunity
=> Could be latent autoimmune diabetes in adults (LADA)
=> Measure islet cell antibodies
What is the best diet for an obese patient with type 2 diabetes?
Dietary carbohydrates = big determinant of post-prandial glucose levels & low carbohydrate diets improve glycemic control
=> low carb ketongenic diet better at maintaining/lowering blood glucose than low glycemic/reduced calorie diet
What preventative measures are taken before starting medications for diabetes?
Education and lifestyle choices
- Exercise to increase insulin sensitivity
- Healthy diet (less saturated fats, sugars, more starch carbs, moderate protein)
- Negotiate HbA1c and review 3-6 monthly
- Assess vascular risk: control BP, initiate high intensity atorvastatin if needed
- Foot care
- Advice to not drive if hypoglycaemic spells - inform DVLA
* Bariatric surgery may be a cure for T2DM in selective patients
How do you manage type 2 diabetes?
Lifestyle modification - diet, exercise, weight control => always consider first and then alongside meds
- Monotherapy: Metformin - 1st line therapy
- If HbA1c >58mmol/mol, start dual therapy
=> Metformin + DPP4 inhibitor e.g. sitagliptin
=> Metformin + pioglitazone
=> Metformin + sulphonylurea (SU)
=> Metformin + SGLT-2i e.g. glifazon - If HbA1c still >58mmol/mol, start triple therapy
=> Metformin + DPP4 inhibitor + SU
=> Metformin + pioglitazone + SU
=> Metformin + SU/pioglitazone + SGLT-2i
If triple therapy doesn’t work, try:
=> Metformin + SU + GLP 1 mimetic
=> Insulin based therapy
What class of drug is metformin?
What is its mechanism of action?
What are its side effects?
Biguanide => works by increasing insulin sensitivity & helps weight
Side effect: nausea, diarrhoea (try modified release version), abdominal pain
=> does not cause not hypoglycaemia
=> avoid if eGFR <36ml/min - risk of lactic acidosis
What are DPP4 inhibitors?
What is its mechanism of action?
DPP4 inhibitors (aka gliptins) e.g. sitagliptin block the action of DPP4
=> DPP4 is an enzyme which destroys the hormone incretin
=> Incretins decrease blood glucose levels => released after eating and augment secretion of insulin
What are Glitazone?
What is its mechanism of action?
What are its side effects?
Glitazone increases insulin sensitivity
Side effects: hypoglycaemia, fractures, fluid retention, raised liver function test (do LFT every 8wks for 1 year)
Contraindications: past/present congestive cardiac failure, osteoporosis => monitor weight & stop if weight increasing or oedema
What are sulphonylurea?
What is its mechanism of action?
What are its side effects?
Sulphonylurea increases insulin secretion e.g. gliclazide 40mg/d
Side effects: hypoglycaemia (monitor glucose) ; weight increase
What are SGLTI?
What is its mechanism of action?
What are its side effects?
Selective sodium-glucose co-transporter-2 inhibitor => blocks reabsorption of glucose in the kidneys and promotes excretion of excess glucose in the urine
