Diabetes mellitus Flashcards
1) What percentage of people with DM have type 1?
2) What is a normal capillary blood glucose level?
3) What is DM characterised, defined and diagnosed by?
4) In DM, what do patients have difficulty in doing?
1) 10%
2) 3.5-8mmol/litre.
3) high CBG levels.
4) Patients have difficulty moving glucose from the blood into cells.
In basic terms in T1DM, what is the underlying pathophysiology?
The pancreas does not make enough insulin due to a type IV hypersensitivity response where a person’s T cells attack the pancreas. This is caused by a cell-mediated immune response.
In T1DM, there is a genetic abnormality which causes what?
Loss of self tolerance amongst T cells.
Causes T cells to attack Beta cell antigens.
T cells recruit other cells which also attack Beta cells.
Loss of Beta cells = less insulin produced = more glucose in the blood.
1) What are the 2 HLA genes which most people with T1DM have in common?
2) What do HLA genes code for?
3) If a person has T1DM predisposition genes, what can cause them to develop T1DM?
1) HLA-DR3 and HLA-DR4.
2) MHC proteins which are important for foreign antigen presentation and self-tolerance.
3) Environmental factors can then trigger beta cell destruction.
Name 5 environmental associations which may trigger beta cells destruction and T1DM development in susceptible patients.
1) Viruses - human enterovirus
2) Dietary factors - cow’s milk, early cereal introduction. vitamin D may be protective.
3) Coeliac disease
1) What percentage of beta cells need to be destroyed before symptoms appear in a patient?
2) When does destruction of beta cells usually begin?
3) What does beta cell destruction proceed subclinically as?
4) How long can the subclinical phase of T1DM last for?
5) What occurs when 80-90% beta cells have been destroyed?
1) 90%
2) Early in life.
3) Insulinitis.
4) Months to years.
5) Hyperglycaemia.
Basically, describe the pathophysiology of T2DM.
The pancreas produces insulin, but the tissue cells do not respond to it. This is because the tissue cells do not move glucose transporter cells to the cell membranes and so the cells cannot take up glucose.
This is known as insulin resistance.
Name 3 factors which can aggravate insulin resistance in patients with T2DM.
Ageing, physical inactivity and obesity.
Name 3 risk factors for the development of T2DM.
Obesity, lack of exercise and HTN.
** Genetics also plays a role.
1) What role does obesity play as a risk factor for T2DM?
2) In T2DM, when the tissues do not respond well to normal levels of insulin, what happens?
1) It is thought that excess adipose tissue releases free fatty acids and adipokines which can cause inflammation.
2) The body must produce more insulin in order to achieve the same effect.
1) How does the body produce more insulin initially in patients with T2DM and insulin resistance?
2) Eventually in patients with T2DM, why do insulin levels then decrease?
3) When do clinical symptoms tend to appear in patients with T2DM?
1) Beta cell hyperplasia and hypertrophy.
2) Because increased production is not sustainable, so beta cells undergo hypotrophy and hypoplasia so insulin levels decrease.
3) When the insulin levels begin to decrease.
**In T2DM, DKA does not usually develop as there is still some insulin present.
Name 6 main presenting factors of T1DM.
Weight loss Polyphagia Glycosuria Polyuria Polydipsia Blurred vision
Describe why weight loss occurs in patients with T1DM.
Glucose in the blood cannot enter cells.
This leaves cells starved of energy.
Adipose tissue starts breaking down fat for energy.
Muscle tissue starts breaking down muscle protein for energy.
This causes weight loss.
Describe why polyphagia occurs in patients with T1DM.
Patients experience increased hunger due to the high catabolic state and the fact that the body is not covering glucose to energy.
Describe why glycosuria occurs in patients with T1DM.
There are such high levels of glucose in the blood, not all of it is reabsorbed and so is secreted and spills over into the urine.
Describe why polyuria occurs in patients with T1DM.
Glucose is osmotically active, so increased glucose in the urine causes increased volumes of water to be secreted into the urine. So water follows glucose, and so with glycosuria there will be an increased urine volume.
Describe why polydipsia occurs in patients with T1DM.
Polyuria causes patients with diabetes to become dehydrated and therefore thirsty.
Describe why blurred vision occurs in patients with T1DM.
Blurred vision occurs with high or fluctuating glucose levels.
Increased levels of glucose damage the retina.
Increased levels of glucose can also cause damage to the blood vessels supplying the retina.
Increased levels of glucose can also cause the lens in the eye to swell.
1) What is a main difference in presentation between patients with T1 and T2 diabetes mellitus?
2) How is type 2 diabetes often detected?
1) T2DM presents more insidiously than T1DM. T1DM tends to cause symptoms over days to weeks, whereas T2DM causes symptoms over months.
2) Through screening.
Name 6 features of clinical presentation which are more common in patients with T2DM.
Candidal infections Skin abscesses Fatigue Paraesthesia Acanthosis nigrans Frequent UTIs
Aside from type 1 and type 2 DM, name two other subtypes of diabetes mellitus.
1) Gestational diabetes: where pregnant women have an increased CBG.
2) Drug-induced diabetes.
Describe gestational diabetes.
Usually occurs in the third trimester of pregnancy. It is thought to be caused by hormones which interfere with insulin’s action on insulin receptors.
Describe drug induced diabetes.
Medications can have side effects which tend to increase blood glucose levels. Mechanisms are thought to be related to insulin resistance.
State the diagnostic levels that the WHO uses for diabetes mellitus for the following investigations:
a) Random plasma glucose
b) Fasting plasma glucose
c) HbA1c\d
d) Oral glucose tolerance test
a) >11mmol/L
b) >6.9mmol/L
c) >/=48mmol/L
d) >11mmol/L
Describe how fasting C peptide can be used as a diagnostic investigation for diabetes mellitus.
C-peptide is produced when insulin is produced from pro-insulin.
Levels of C-peptide reflect insulin production.
So, fasting C-peptide can be helpful in differentiating between T1 and T2 DM.
**In T1DM, fasting C-peptide levels will be low or undetectable because insulin is not being produced or is only being produced at very low levels.
Describe results which would be indicative of pre-diabetes for the following investigations:
a) Fasting blood glucose
b) Random blood glucose
c) Oral glucose tolerance test
d) HbA1c
a) >6.1
b) >7.8
c) >7.8
d) 42-48
1) How do you reduce the risk of micro- and macrovascular complications in patients with diabetes mellitus?
1) Through intensive glycaemic control.
1) How do you reduce the risk of micro- and macrovascular complications in patients with diabetes mellitus?
2) What is a major cause of death and morbidity in patients over 30 with DM?
3) What is the main cause of death in patients under 30 with DM?
1) Through intensive glycaemic control.
2) CVD.
3) Acute diabetic complications.
Describe how often HbA1c should be monitored for patients with diabetes.
HbA1c should be checked twice yearly for patients with T1DM meeting their Rx goal:
- <59 for patients <18 years with T1Dm
- <53 for adults.
HbA1c should be checked monthly for patients with T1DM not meeting their Rx goal.
In adults with type 2 diabetes, measure HbA1c levels at:
- 3–6-monthly intervals (tailored to individual needs), until the HbA1c is stable on unchanging therapy
- 6-monthly intervals once the HbA1c level and blood glucose lowering therapy are stable.
1) How should BP be monitored in patients with DM?
2) When should lipid profiles be monitored in patients with DM?
3) Describe how diabetic retinopathy should be monitored.
1) Check BP at each patient visit.
2) At diagnosis and then every 5 years.
3) At diagnosis and then annually if >12 years.
Describe the blood pressure targets for patients with diabetes outlined by NICE.
- T1DM: <135/85
- T2DM: <140/80
- Patient with diabetic nephropathy, diabetic retinopathy, cerebrovascular disease or 2 signs of metabolic syndrome: <130/80
Name 3 other areas which should be monitored annually for patients with diabetes mellitus.
eGFR in patients with DM for >5 years.
Distal polyneuropathy
Dental exams to control periodontal disese
Which 3 conditions should there be a low threshold for screening for with patients with diabetes?
Thyroid diseases
Coeliac disease
Depression
What is the first line management option for patients with T1DM?
How does this method of management work?
First line treatment is with basal bolus insulin. An initial basal dosing of insulin is given each day alongside insulin boluses which are given before meals.
1) What is the initial total daily dose of insulin that is prescribed?
2) How are meal time insulin doses given?
3) What type of insulin is used for the basal doses?
4) What type of insulin is used for bolus doses?
1) 0.2-0.4 units/kg/day
2) As a range of doses (i.e. certain insulin dose for a certain meal size) or through carbohydrate counting.
3) Intermediate/ long acting insulins
4) Short/ rapid acting insulins.
Describe when short or rapid acting insulin boluses should be administered with regards to meal times.
Short acting insulins should be given 30 minutes prior to a meal.
Rapid acting insulins should be given 15 minutes before a meal or very shortly after a meal.
Name 2 adjunct treatments which can be used for patients with type 1 diabetes mellitus.
1) Pre-meal correction insulin: can be added to bolus insulin based on pre-meal blood glucose measurements.
2) Amylin anaglogues: reduces post prandial glucose increases by prolonging gastric emptying time and reduces food intake through centrally mediated appetite suppression. (e.g. Pramlintide)
1) Which patients is use of Amylin often reserved for?
2) What combination of insulins can be used in order to provide better background blood glucose maintenance?
3) What is a main benefit of rapid acting insulins?
1) Mainly used for patients with post-prandial hyperglycaemia that cannot be controlled with pre-meal insulin alone.
2) Short acting can be combined with longer acting (30:70 ratio) for better background maintenance.
3) Offers patients more flexibility over when meals are eaten.
Name 4 short acting insulins.
Actrapid
Humulin S
Velosulin
Hypurin Natural
Name 3 rapid acting insulins.
Novorapid
Humalog
Insulin lispro
**Rapid acting insulins act quickly to minimise rises in blood sugar.
Name 2 intermediate acting insulins.
Hypurin Isophane
Humulin I
Give 3 examples of long acting insulins.
Insulin glargine Insulin determine Insulin degludec Hypurin Bovine Lente Hypurin Bovine Pzi (activity can last for up to 36 hours)
- *Long acting insulins are appropriate in those with hyperglycaemia throughout the day and night.
- **Useful for those needing help with injections as activity can last for up to 24 hours.
1) What is the first stage of management for patients with T2DM?
2) What is often the second line management for patients with T2DM?
3) When do you move up a step of the T2DM management ladder?
1) Lifestyle modifications.
2) Monotherapy normally with metformin.
3) If the current level of therapy is not sufficient to keep HbA1c below target (<58).
State 6 lifestyle modifications that need to be suggested for patients with T2DM.
- Increased complex carbs, less simple carbs.
- Exercise and weight loss
- Decreased alcohol intake
- Substitute sugars for artificial sweeteners
- Eat low glycaemic index foods
- Spread nutrient load throughout the day to reduces blood glucose swings (eat 3 meals a day).