Diabetes Mellitus Flashcards
What are the diagnostic criteria for diabetes mellitus?
Symptoms + one +ve test.
Assymptomatic + 2 +ve tests.
Fasting blood glucose >6.9mmol/L
Oral glucose tolerance test >11.1mmol/L
Random blood glucose >11.1mmol/L
HbA1c greater than 48mmol (if patient is asymptomatic should be repeated) Not suitable for diagnosing Type 1.
What are the diagnostic criteria for impaired glucose tolerance and impaired fasting glycaemia?
Impaired glucose tolerance:
OGTT 7.8-11
Impaired fasting glycaemia:
6.1-6.9
What are the different types of DM?
Type 1: Autoimmune destruction of the islet cells of the pancreas.
Type 2: Insulin receptors become unresponsive to insulin due to over exposure.
Secondary: Diabetes caused by another disease.
MODY (maturity onset diabetes of the young):- autosomal dominant slow progressing type 2
LADA (latent autoimmune diabetes of adulthood):- slow onset type 1 presentation
Gestational
Outline the causes of secondary diabetes?
Pancreatic damage following: recurrent pancreatitis, neoplasia, surgery.
Cystic Fibrosis.
Haemochromatosis.
Cushings, Polycystic Ovary Syndrome.
Compare and contrast the typical presentations of Type 1 and 2 diabetes?
Type 1: Onset usually in the young Weight loss May present with ketoacidosis (vomiting and unwell) Usually comes on quickly weeks - months
Type 2:
Usually in older people but more recently younger populations due to childhood obesity.
Associated with being overweight.
Onset is more insidious.
Both present with polyuria and polydypsia
Describe the principle of dietary treatment of diabetes?
Type 1: Calculate the glycaemic index of your food and adjust your insulin appropriately. Lower GI carbs are preferential.
Type 2: Weight loss if patient is overweight. Balanced diet which is low in sugar and fat. Lower GI carbs.
Describe the different methods of evaluating diabetic control?
Urine dip:
Crude measurement which can detect when there are high levels of glucose therefore it can not all be reabsorbed therefore it is present in urine. Can also detect urinary ketones.
Self monitored BM testing:
Snapshot of blood glucose control, will vary greatly depending on food. Important in assessing hypoglycaemic attacks. But a singular BM cannot give any indication regarding long term control.
HBA1c:
Measures the degree of glycation of Hb and therefore can give an indication of medium term control.
48mmol/L is the cut off for diabetes (6.5%)
75mmol/L = poor control (9.0%)
Describe the basal bolus insulin regimen?
Basal bolus: -Bedtime long-acting + short acting before each meal -Adjust dose according to meal size -Roughly 50% of insulin given as long-acting
What are the other insulin regimen’s available?
Insulin Pump: Only for expert patients
Portable devices attached to the body that continuously deliver amounts of rapid or short acting insulin via a catheter placed under the skin. Amount given can be adjusted to meals.
BD Biphasic Regime
- BD insulin mixture 30min before breakfast and dinner
- Contains a rapid-acting and intermediate- / long-acting
- 2/3 of the insulin is given in the morning
OD Long-Acting Before Bed
-Initial regime when switching from tablets in T2DM
What are the circumstances in which a persons insulin requirement will increase/decrease?
Increased insulin requirements: Infection Trauma Stress Pregnancy
Decreased insulin requirements: Coeilac disese Addison's disease Hepatic impairment Renal impairement
Describe the management of Type 2 diabetes?
Lifestyle advice:
Lose weight
Exercise
Reduce simple carbs, sugars and fats (risk of CVD)
Pharmaceutical:
1st line: Overweight?
Yes = Metformin
No = Sulphonylureas (gliclazides) if renal impairment 1st line
2nd line : Take 2 metformin and a sulphonylurea (or a glitazone if others are not tolerated)
3rd line: Insulin +/- metformin
BP raised above 140/80 or renal impairment give an ACEi
Describe the mechanism of action of metformin and important side effects?
- Decreases hepatic glucose production
- Decreases intestinal absorption of glucose
- Improves insulin sensitivity by increasing peripheral glucose uptake and utilisation.
Side effects:
- GI upset (nausea, vomiting and diarrhoea)
- lactic acidosis
Describe the mechanism of action of sulphonylureas and give the important side effects?
Inhibit ATP-sensitive potassium channels. This causes the cell to depolarise causing there to be an influx of calcium and insulin to be secreted.
AKA increases insulin secretion.
S/e:
Cause weight gain (+increase insulin resistance), often avoided in obesity.
Associated with hypo’s particularly in:
The elderly
People who skip meals
Long acting sulphonylurea agents (glibencamide)
Describe the mechanism of action of thiazolindiediones (‘glitazones’)?
Alters gene expression resulting in a insulin sensitising effect aka increase glucose uptake.
Effects include:
- reduced hepatic glucose output
- increased glucose transporters (GLUT) in skeletal muscle with increased peripheral glucose utilization
- increased fatty acid uptake into adipose cells
What are the common side effects of thiazolindiediones?
Oedema and heart failure.
Weight gain.
Macular oedema.
Increased risk of #
When combined with other antihyperglycaemics can cause hypos.
