Diabetes - Classification & Diagnosis Flashcards
If a patient is symptomatic of hyperglycaemia, how many abnormal blood glucose or HbA1c results must be obtained for them to be diagnosed with diabetes?
One
If a patient is asymptomatic, how many abnormal blood glucose or HbA1c results must be obtained for them to be diagnosed with diabetes?
Two (on two separate occasions)
What are the major symptoms of hyperglycaemia?
Polyuria, polydipsia, weight loss, fatigue
A fasting blood glucose of greater than or equal to what value is suggestive of a diagnosis of diabetes mellitus?
7mmol/L
A random blood glucose of greater than or equal to what value is suggestive of a diagnosis of diabetes mellitus?
11.1mmol/L
A blood glucose level of greater than or equal to what two hours after an oral glucose tolerance test is suggestive of a diagnosis of diabetes mellitus?
11.1mmol/L
An HbA1c value of greater than or equal to what is suggestive of a diagnosis of diabetes mellitus?
48mmol/mol (6.5%)
Does having an HbA1c value of < 48mmol/mol rule out a diagnosis of diabetes mellitus?
No
HbA1c provides a measure of glycaemic control over what time period?
The previous 2-3 months
An HbA1c value of greater than what is suggestive of poor diabetic control?
75mmol/mol
An HbA1c or blood glucose value which falls between the normal value and the value which is diagnostic of diabetes mellitus can be defined as what?
Pre-diabetes
A normal HbA1c value is what value or less?
41mmol/mol
A normal fasting blood glucose level is what value or less?
6mmol/L
A normal random blood glucose level is less than what value?
11.1mmol/L
A normal blood glucose level 2 hours after an oral glucose tolerance test is what value or less?
7.7mmol/L
Type 1 diabetes is usually adolescent in onset, but has a secondary peak when?
Late 30s
Type 1 diabetes is a state of absolute insulin deficiency as a result of what?
Autoimmune destruction of pancreatic beta cells
Type 1 diabetes has strong associations with other autoimmune conditions because > 90% of those affected by it carry at least one of which two genes?
HLA-DR3 and/or HLA-DR4
Type 1 diabetes has a most significant overlap with which other autoimmune condition? If you are testing for type 1 diabetes autoantibodies, you should test for which other ones at the same time?
Coeliac disease - also test for anti-TTG antibodies
What is the concordance rate of type 1 diabetes in identical twins?
30%
What is a rare form of type 1 diabetes which involves a slower progression to insulin dependence in later life?
Latent autoimmune diabetes of adults (LADA)
Polyuria associated with type 1 diabetes may present as what in children?
Enuresis
What is the concordance rate of type 2 diabetes in identical twins?
> 80%
What is a rare form of type 2 diabetes which affects young people with a strong family history?
Maturity onset diabetes of the young (MODY)
What are some pancreatic conditions which may cause secondary diabetes mellitus?
Chronic pancreatitis, haemochromatosis, CF
What are some examples of drugs which may cause secondary diabetes mellitus?
Glucocorticoids, thiazide diuretics, beta blockers
What are the 4 main features of metabolic syndrome (syndrome X)?
Central obesity, hypertension, hyperlipidaemia, insulin resistance
The presence of ketones on urinalysis is most suggestive of which type of diabetes mellitus?
Type 1
What are 3 useful tests for ruling out type 1 diabetes?
GAD/islet cell autoantibodies, C-peptide, ketones
Blood ketones of greater than what value would be considered significant?
1.5mmol/L
Blood ketones of greater than what value would be suggestive of DKA?
3mmol/L
What is important to be aware of when testing C-peptide levels for type 1 diabetes?
Some people with type 1 diabetes may retain C-peptide for a few years after they stop producing insulin
What diagnosis should be suspected in individuals aged around 25-40 who present with symptoms of diabetes, are non-obese and may have other autoimmune conditions?
LADA
Permanent neonatal diabetes usually occurs within what timeframe?
The first 6 months of life
Children who are diagnosed with neonatal diabetes are most likely to have what underlying type of the condition?
MODY
What is the target HbA1c value for all type 1 diabetic patients and type 2 diabetic patients on lifestyle or lifestyle + metformin management?
48mmol/mol
How is MODY inherited?
Autosomal dominant
Which subtype of MODY is caused by a defect in the glucokinase enzyme on chromosome 7?
MODY2
Which subtype of MODY involves mild, asymptomatic and stable hyperglycaemia which is present from birth?
MODY2
How is MODY2 usually managed?
Lifestyle management only
What is the most common type of MODY?
MODY3
Which subtype of MODY involves severe hyperglycaemia after puberty which is progressive?
MODY3
How is MODY3 usually managed?
Sulfonylureas
Which subtype of MODY is associated with pancreatic atrophy, renal abnormalities and genital tract malformations?
MODY5
What is a useful test for distinguishing between type 1 diabetes and MODY?
C-peptide
Gestational diabetes can be diagnosed if there is a blood glucose of what or more after an OGTT?
7.8mmol/L
What is the screening test used to detect gestational diabetes?
Oral glucose tolerance test
How should patients who have had gestational diabetes be followed up for their risk of developing type 2 diabetes?
Fasting blood glucose 6 weeks post-partum and annual review
Pregnant (and pre-conception for planned pregnancy) diabetic patients should aim for an HbA1c of what value or less?
43mmol/mol
Pregnancy should be avoided if HbA1c is greater than what value?
85mmol/mol
What supplement should be given to diabetic patients pre-conception?
5mg folic acid
What are some drugs, commonly taken by diabetic patients, which must be stopped in pregnancy?
Most oral hypoglycaemic agents (except metformin), ACE inhibitors/ARBs, statins
How should foetal growth be monitored in babies of diabetic mothers?
4 weekly growth scans from 28 weeks onwards
What happens to the insulin requirement in pregnancy?
Increases by 50-100%
NICE recommends delivery at what gestation for a) pre-existing and b) gestational diabetes?
a) 38 weeks b) 40 weeks
What may cause an individual to have a falsely high HbA1c result?
Splenectomy
Conditions such as sickle cell anaemia, G6PD deficiency and hereditary spherocytosis, along with blood donation, have what effect on HbA1c results?
Falsely low