diabetes pathogenesis and metabolic abnormalities 3 W6

Question 1

spectrum of dysglycaemia?

Answer 1

fasting blood glucose levels:

normal = <6.0mmol/l
impaired fasting glycaemia = 6.0-7.0mmol/l
diabetes = >7.0mmol/l

Question 2

measurements to define diabetes?

Answer 2

fasting plasma glucose ≥7.0mmol/l
2hr plasma glucose in OGTT ≥11.1mmol/l
random plasma glucose ≥11.1mmol/l
HbA1c ≥48mmol/mol

Question 3

what is HbA1c? what’s it used for?

Answer 3

glycated haemoglobin
measure of average glycemia
reflects integrated blood glucose concentrations during the lifespan of erythrocytes (120 days)
can be measured at any time of day, irrespective of food consumption

Question 4

HbA1c measurement interpretation?

Answer 4

normal ≤41mmol/mol
pre-diabetes 42-47mmol/mol
diabetes ≥48mmol/mol

Question 5

situations when HbA1c should not be used as a diagnostic test?

Answer 5

rapid onset of diabetes
pregnancy
conditions where red cell survival may be reduced
increased red cell survival
renal dialysis
iron and vitamin B12 deficiency

Question 6

rapid onset of diabetes can occur when?

Answer 6

suspected type 1 diabetes
children
drugs - steroids, antipsychotics

Question 7

why cant HbA1c be used as a diagnostic test for diabetes in pregnancy

Answer 7

glucose levels can rise rapidly
HbA1c is lower

Question 8

conditions where red cell survival may be reduced?

Answer 8

haemoglobinopathy
haemolytic anaemia
severe blood loss
splenomegaly
antiretroviral drugs

Question 9

conditions with increased red cell survival?

Answer 9

splenectomy

Question 10

why can’t HbA1c be used as a diagnostic test in renal dialysis?

Answer 10

reduced HbA1c, especially if treated with erythropoietin

Question 11

why cant HbA1c be used as a diagnostic test in iron and vitamin B12 deficiency?

Answer 11

small effects on HbA1c

Question 12

when can be HbA1c be used as a test in people who already have established diabetes?

Answer 12

as a monitoring tool, allows evaluation of:
-efficacy of therapeutic regimen
-adherence to treatment
-risk of developing diabetic complications

Question 13

what is the OGTT used to assess and how is it carried out?

Answer 13

used to assess state of glucose intolerance
75g oral glucose load
no restriction or modification of carbohydrate intake for preceding 3 days
fast overnight
test performed in the morning - seated, no smoking
blood samples for plasma glucose taken at 0hrs and 2hrs

Question 14

how is impaired glucose tolerance specifically identified?

Answer 14

using a glucose tolerance test

Question 15

impaired glucose tolerance measurements?

Answer 15

fasting plasma glucose <7.0mmol/l
2 hrs after 75g oral glucose load 7.8-11.0mmol/l

Question 16

impaired glucose tolerance features?

Answer 16

affects 20% of uk population aged 40-65yrs
increased morality from cardiovascular disease
natural history - 15% develop diabetes in 5 yrs, 15% return to normal
check fasting plasma glucose annually

Question 17

impaired fasting glucose (IFG) (fasting hyperglycaemia) - fasting glucose levels?

Answer 17

fasting plasma glucose in IFG 6.0-6.9mmol/l

Question 18

impaired fasting glucose features?

Answer 18

intermediate state between normal glucose metabolism and diabetes
impaired glucose tolerance often present
found in 5% of population, prevalence increases with age
increased risk of vascular complications

Question 19

pre-diabetic states test measurements?

Answer 19

fasting blood glucose 6.0-6.9mmol/l
2hr OGTT blood glucose 7.8-11.0mmol/l
HbA1c 42-47mmol/mol