Diabetes: diagnosis, epidemiology + complications Flashcards
(25 cards)
Clinical diagnosis criteria for type 1 diabetes
hyperglycaemia +
- ketosis
- rapid weight loss
- age onset <50y
- BMI <25
- personal and/or family history of autoimmune disease
Diabetes complications
retinopathy
nephropathy
foot problems
circulation problems
pregnancy
personal impact + quality of life
Vascular complications of type 2 diabetes at time of diagnosis
retinopathy
nephropathy
erectile dysfunction
ischaemic skin changes
abnormal vibration threshold
cerebrovascular disease
abnormal ECG
hypertension
intermittent claudication
absent foot pulses
What causes type 1 diabetes?
destruction of pancreatic beta cells leading to absolute insulin deficiency
What are type 1A and type 1B diabetes?
1A = autoimmune destruction of pancreatic beta cells
1B = patients with absolute insulin deficiency with no evidence of autoimmunity or other known cause of beta cell destruction
What autoantibodies can be found in T1DM?
Glutamic acid decarboxylase (GAD)
Islet antigen 2 (IA-2)
Insulin (IAA)
ZnT8
What are some triggers of T1DM?
chemicals
viruses (mumps, rubella, CMV, enteroviruses)
bacteria
intrauterine factors (pre-eclampsia, maternal rubella, caesarean section, birth weight)
diet (vit D deficiency, milk protein)
stress
Clinical presentation of T1DM?
acute onset with classical osmotic symptoms
weight loss predominates (catabolism of protein and fat resulting from profound insulin deficiency)
5-10% present with DKA
What causes T2DM?
peripheral insulin resistance with a relative (rather than absolute) deficiency in insulin secretion
- decreased glucose uptake in muscle, fat and the liver
- excess hepatic glucose output
- a pancreatic beta-cell insulin secretory deficit
Factors that affect insulin secretion and action
body weight
level of physical activity
smoking
heavy alcohol consumption
genetic predisposition
gene-environment interaction
epigenetics
gestational diabetes mellitus
T2DM clinical presentation
onset of disease is often slow, diagnosis is often delayed - many patients present with complications of chronic hyperglycaemia
some cases are detected incidentally
What is pre-diabetes and what is the threshold?
impaired fasting glycaemia
glucose 6-7 mmol/L
What are the WHO criteria for diabetes diagnosis?
in presence of symptoms:
- random plasma glucose >11.1 mmol/L
OR
- fasting plasma glucose >7 mmol/L
OR
- 2 hour plasma glucose >11.1 mmol/L 2 hours post 75g OGTT
in asymptomatic individuals, at least one of the above criteria fulfilled on 2 separate occasions
What is the WHO HbA1C criteria for diabetes diagnosis and who can it be used for?
HbA1C > 48 mmol/mol (6.5%) with symptoms and plasma glucose >11.1 mmol/L
OR
HbA1C > 48 mmol/mol (6.5%) in asymptomatic patient
not to use in children and young people, T1DM, symptoms within 2 months, pregnancy, drugs causing hyperglycaemia or blood conditions affecting Hb
How is HbA1C formed and what does it reflect?
formed by glycation of haemoglobin as it is exposed to plasma glucose
reflects average plasma glucose over the previous 8-12 weeks
When is HbA1C unreliable?
pregnancy
symptom onset within 2 months
anaemia and haemoglobinopathies
children and young people
acutely ill
How is an oral glucose tolerance test carried out?
overnight fast (>8 hours)
fasting plasma glucose
75g anhydrous glucose to drink
2nd blood sample 2 hours later
7.8-11 mmol/L = pre-diabetes
>11 mmol/L = diabetes
When is oral glucose tolerance test used?
used for gestational diabetes and where HbA1C is unreliable
4 main aims of diabetes management
minimisation of long-term complications
minimisation and prevention of hyperglycaemic diabetic emergencies (DKA/HHS)
minimisation of osmotic symptoms
avoidance of iatrogenic side-effects eg. hypoglycaemia
Macrovascular diabetes complications
coronary artery disease
cerebrovascular disease
peripheral vascular disease
Microvascular diabetes complications
nephropathy
retinopathy
autonomic neuropathy
peripheral sensory neuropathy
mononeuropathy
How does hyperglycaemia accelerate atherosclerosis?
increased endothelial permeability
increased presence of reactive oxygen species leading to increased oxidation of LDL
upregulation of cytokines leading to increased proliferation of smooth muscle in plaques
Definition of diabetic nephropathy
presence of dipstick positive proteinuria in a patient with diabetes
(equates to urinary albumin conc 300mg/L or greater)
Distribution of diabetic neuropathy
glove and stocking
distal symmetrical sensorimotor polyneuropathy
