Diabetes 2 Flashcards
1
Q
What can be measured by Urine Analysis in Diabetic Patients?
A
Detection of glucose in urine (glycosuria)
- Usually used as first line screening test
- Normally plasma glucose would have to be >10 mmol/L for glucose to be detected in urine. Can be detected using basic urine test strip / dipstick
- Test strips directly placed into urine – different colour responses reflect glucose concentration
Detection of ketones in urine (ketonuria)
- Can have qualitative detection using urine test strips/ dipstick
- Test strips will not detect β-hydroxybutyric acid
- Ketones may be present in normal individuals
2
Q
What is Microalbuminuria?
A
Defined as excretion of 30-300 mg of Albumin/24hrs
- Urine dipsticks are not sensitive enough at this concentration. Measurement important for diabetic patient.
- Signals of early reversible renal damage
3
Q
What is commonly measured for Microalbuminuria?
A
Albumin to creatinine ratio (ACR) commonly measured
- More convenient than 24hr urine collection
- NICE recommend early morning urinary ACR
- Upper limit of normal: 2.5 mg/mmol in men, 3.5 mg/mmol in women
4
Q
What is used to estimate Blood Glucose?
A
Venous plasma glucose
- Some laboratories accept serum samples for monitoring
- Samples should be analysed quickly
- Glucose 10-15% higher in plasma / serum than whole blood
5
Q
What are 2 types of Blood Analysis?
A
Fasting glucose sample
- Glucose measured after at least 8 hours overnight fast
- Generally considered a more reliable sample than random glucose
- Can be used for diagnosis (see criteria)
Random glucose sample
- Measured at any time regardless of fasting state
- Usually measured during emergency situations
- Can also be used for diagnosis (see criteria)
6
Q
How is the Oral Glucose Tolerance Test carried out?
A
Used mainly in pregnant women to test for gestational diabetes. Sometimes used in patients have borderline results
Before the test
- Three days of unrestricted diet and usual exercise
- An evening meal (30 – 50g carbohydrate) consumed night before
- An overnight fast of 8 – 14 hours is required
The Test
- Fasting plasma glucose taken first (am)
- Patient drinks 75g of anhydrous glucose dissolved in 250 – 300 ml water over 5 minutes
- Second plasma glucose taken 2 hours
7
Q
What are considerations for OGTT?
A
- No smoking during the test
- Patient should rest during the test
- Medications / infections at the time of the test should be recorded
- Glucose must be measured in laboratory
8
Q
How is diagnosis of diabetes using HbA1c?
A
- Diabetes Mellitus: ≥48 (in the presence of symptoms). If asymptomatic repeat within 2wks
- High risk: 42 - 48(monitor annually)
- Low risk / Normal: ≤ 41
9
Q
What is Impaired Fasting Glucose?
A
Fasting plasma glucose ≥ 6.1 and < 7.0 mmol/L and 2hr OGTT <7.8 mmol/L
- Intermediate state between normal glucose tolerance and diabetes
- Presents in 5% of the population and increasing with age
- Increased risk of micro and macrovascular complications
10
Q
What is Impaired Glucose Tolerance?
A
Fasting plasma glucose < 7.0 mmol/L and OGTT 2hr ≥ 7.8 mmol/L but < 11.1 mmol/L
- Intermediate state between normal glucose tolerance and diabetes
- Individuals often manifest hyperglycaemia only when challenged with oral glucose in an OGTT
- 2-5% of people with IGT per year progress to diabetes
- IGT associated with increased risk of developing cardiovascular disease
11
Q
What is the criteria for diagnosis of Diabetes?
A
If patient has clinical symptoms (Polyuria, polydipsia or weight loss)
- A single random venous plasma glucose of ≥ 11.1 mmol/L
or
- Fasting venous plasma glucose of ≥ 7.0 mmol/L
or
- 2 hour plasma glucose in OGTT ≥ 11.1 mmol/L is diagnostic
If patient DOES NOT have clinical symptoms
- At least two elevated plasma glucose readings must be taken on separate days ie ≥ 7.0 mmol/L fasting, ≥ 11.1 mmol/L random
12
Q
What are diagnosis criteria of Gestational Diabetes?
A
NICE
- Fasting Glucose = ≥5.6
- Two Hour Glucose = ≥7.8
SIGN
- Fasting Glucose = ≥5.1
- One Hour Glucose = ≥10
- Two Hour Glucose = ≥8.5
13
Q
What is HbA1c?
A
- Product of non-enzymatic addition of glucose residue to beta chain to haemaglobin
- Can be measure in a lab and used in diagnosis
- HbA1c is a long term measure of glycaemic control in patients with DM
- Should NOT be used in diagnosing patient suspected of having Type 1 DM
14
Q
How is Glycated haemoglobin formed?
A
- Glucose in blood taken up by RBC
- Non-enzymatic condensation reaction of glucose to N-terminal valine residues of β Chain
- Reaction is irreversible
- % glycosylated haemoglobin depends on mean glucose level over the lifespan of a red blood cell (~ 120 days)
15
Q
Why do we measure HbA1c?
A
- DCCT & UKPDS showed that HbA1c is the best long-term marker of diabetes control
- Better control of HbA1c leads to better outcomes in people with diabetes
16
Q
When should HbA1c not be used for diagnosis?
A
- Children and young people
- Patients suspected of having type 1 diabetes
- Patients with symptoms of diabetes for less than two months
- Patients at high diabetes risk who are acutely ill
- Patients taking medication that may cause rapid glucose rise eg steroids, antipsychotics
- Patients with acute pancreatic damage
- Pregnancy
- Other factors that influence HbA1c
17
Q
What factors cause an increase of HbA1c?
A
Red Cell Lifespan
- Previous Splenectomy
- Iron deficiency anaemia
- B12 deficiency
- Iron deficiency
- Erythropoiesis
Glycation
- Alcoholism
- CKD
Analytical Interference
- Hyperbilirubinaemia
- High Dose Aspirin
- Opiates
- Carbamylated HB
18
Q
What factors cause a decrease HbA1c?
A
Red Cell Lifespan
- Splenomegaly
- Rheumatoid Arthritis
- Haemolysis
- Erythropoeitin treatment
- B12 treatment
- Iron Treatment
- Drugs such as ribavirn or antiretrovirals
Glycation
- Aspirin
- Vitamin C and E
- Haemoglobinopathies
Analytical Interference
- Hypertriglyceridaemia
19
Q
What factors causes variable HbA1c?
A
Red Cell Lifespan
- Haemoglobinopathies
- HbF
- MetHb
Glycation
- Genetic Heterogenity
Analytical Interference
- Haemoglobinopathies
20
Q
What is Serum Fructosamine?
A
- Refers to glycated serum proteins
- Predominately glycated albumin
- Can be used an alternative to HbA1c as a marker of blood sugar control
- Used in patients with diseases that effect red cell turnover eg haemolytic anaemia, haemoglobinopathies
21
Q
What length of glycaemic levels does serum fructosamine reflect?
A
- Reflects short-term (2–3 weeks) mean glycemic levels
22
Q
What are advantages and disadvantages of Fasting Plasma Glucose (FBG)?
A
Advantages
- Established standard
- Fast and easy
- Single Sample
Disadvantages
- Sample not stable
- Day-to-day variability
- Inconvenient to fast
- Glucose homeostasis in single time point
23
Q
What are advantages and disadvantages of 2hr Plasma Glucose in 75 g OGTT?
A
Advantages
- Established standard
Disadvantages
- Sample not stable
- Day-to-day variability
- Inconvenient, Unpalatable
- Cost
24
Q
What are advantages and disadvantages of HbA1c?
A
Advantages
- Convenient
- Single sample
- Standardized, validated assay required
- Low day-to-day variability
- Reflects long term [glucose]
Disadvantages
- COST (£££)
- Affected by medical conditions, aging, ethnicity
- Not used for age <18, pregnant women or suspected T1DM
25
Capillary blood glucose measured by patients themselves. This is extremely important for Type 1 DM:
* Monitors insulin regimes
* Confirming hypoglycaemia (‘hypo’s’)
* Useful if treatment has changed recently
26
What is the target HbA1c?
**Target HbA1c level of 48 mmol/mol (6.5%) or lower**
* Need to agree an individualized HbA1c target. Based on daily activities, aspirations, likelihood of complications, comorbidities, occupation, and history of hypoglycaemia
* Target should not increase the risk of severe hypoglycaemia
* **HbA1c every 3-6 months (more often if necessary)**
27
What are targets for routine self monitoring of blood glucose levels for all adults?
* Fasting plasma glucose level of **5–7 mmol/L on waking.**
* Plasma glucose level of **4–7 mmol/L before meals.**
* Plasma glucose level of **5–9 mmol/L at least 90 minutes after eating**
* A bedtime target plasma glucose level should be agreed with the person (usually similar to fasting level for ‘walking
28
What are recommended HbA1c treatment targets in patients being managed?
Managed by:
* Lifestyle/diet only = **48 mmol/mol (6.5%)**
* Lifestyle/diet combined with a single drug not associated with hypoglycaemia (such as metformin)= **48 mmol/mol (6.5%)**
* A drug associated with hypoglycaemia (eg sulphonylurea): **53 mmol/mol (7.0%).**
Measure HbA1c levels at 3–6-monthly intervals (tailored to individual needs) until the HbA1c is stable on unchanging treatment, then at 6-monthly intervals
29
When is Self monitoring of blood glucose levels for adults with type 2 diabetes recommended?
**Self-monitoring of blood glucose levels for adults with type 2 diabetes NOT recommeded by NICE except in:**
* Patients that are on insulin
* Patients with evidence of hypoglycaemic episodes
* Patients on oral medication that may increase their risk of hypoglycaemia while driving or operating machinery
30
What other factors need to be monitored in Diabetic Patients apart from Glucose?
* Renal function
* Lipid Profile
31
Why are lipid profiles done in Diabetic Patients?
* Lipid abnormalities are common in patients with diabetes and can increase risk of cardiovascular disease.
* REDUCING THE RISK OF MACROVASCULAR DISEASE can be acheived through interventions.
* Lipids measured to monitor success of lipid lowering therapies: Lifestyle intervention (diet, weight loss, increased physical activity), Medications eg Statins
32
What tests are done in the Lipid Profile?
Full lipid profiles on patients would include:
* Total cholesterol
* Low Density Lipoprotein (LDL) Cholesterol
* High Densioty Lipoprotein (HDL) cholesterol
* Triglycerides
33
How is Diabetic Nephropathy assessed?
**Microalbuminuria**
* Requires sensitive method for albumin measurement
* Can be measured in 24hr urine collection
* Usually Albumin/Creatinine ratio performed instead of 24hr collection
* A/C ratio \>2.5mg/mmol in men or \>3.5mg/mmol in women (consistent with microalbumuria)
**Proteinuria**
* Detectable by urine dipstick
* Can measure 24hr urine protein or protein:creatinine ratio
**Glomerular function**
* Serum creatinine
* Creatinine clearance (CrCl)
* Calculated GFR
34
* **Thyroid diseses (Graves' disease or Hashimoto's thyroiditis)**: Thyroid function tests
* **Addison’s disease:** 9am Cortisol, Short Synacthen Test (SST)
35
What is the treatment for Type 1 Diabetes Mellitus?
Always require Insulin
* Long acting/short acting
* Allows flexibility of lifestyle
* Basal-bolus regimes
36
What is the treatment for Type 2 Diabetes Mellitus?
**Diet**
* Low fat healthy diet
* Reduced calorie diet (if weight loss required)
**Oral Hypoglycaemics**
* Metformin (Increases Insulin sensitivity, Increases glucose uptake, Decreases glucose absorption, Decreases gluconeogenesis)
* Glitazones (Insulin sensitizer)
* Sulphonylureas (Increases Insulin secretion)
* Meglitinides (Increases Insulin secretion)
* Gliptins (Increases Insulin secretion)
* Glucagon like peptide -1 (GLP-1) mimetics (increases Insulin secretion)
**Insulin**
