Diabetes: Aetiology, DIagnosis and Presentation

Question 1

2025 prediction of total number with diabetes in UK

Answer 1

> 5 million

Question 2

Typical Symptoms of Diabetes

Answer 2

Osmotic symptoms:
Polyuria
Polydipsia
Nocturia
Weight loss
Fatigue
Blurred vision
Pruritis
Recurrent UTIs/Genitourinary infections

Question 3

Why do you get osmotic symptoms in diabetes?

Answer 3

• hyperglycaemia

- glucose has osmotic effect

Question 4

What are some diabetes acute emergencies?

Answer 4

HHS = hyperosmolar hyperglycaemic syndrome
DKA = diabetic ketoacidosis

Question 5

Diabetes complications

Answer 5

• skin infections = staphylococcal skin abcesses, oral, genital candidiasis
• foot problems = ulcers, neuropathic pain
• retinopathy = on routine eye test
• acute MI/stroke = whilst in hospital

Question 6

Difference in presentation of type 1 vs. type 2

Answer 6

1 = more acute, emergency
2 = subacute/insidious/non-specific

Question 7

Methods of diagnosis

Answer 7

• FPG (fasting plasma glucose)
• RPG (random plasma glucose)
• OGTT (oral glucose tolerance test)
• HbA1C

Question 8

How does OGTT work?

Answer 8

• fast for min. 9 hours
• check FPG
• give 75g glucose
• check 2 hour PG

Question 9

How does HbA1c work?

Answer 9

• glycated Hb
• measure for average glucose control over 3 month period
• normal <42mmol/mol
• depends of age/co-morbidities
• <53 mmol/mol indicates well controlled diabetes

Question 10

How to diagnose a patient with no symptoms?

Answer 10

2 diagnostic tests required (2 FPG/HbA1C) but only 1 abnormal OGTT

Question 11

How to diagnose a patient with symptoms

Answer 11

1 diagnostic test is enough

Question 12

FPG values

Answer 12

• diabetes = ≥7mmol/L
• normal ≤ 6
• impaired glucose tolerance <7
• impaired fasting glucose = 6.1-6.9

Question 13

2 hour PG values

Answer 13

• diabetes = ≥ 11.1mmol/L
• impaired glucose tolerance = 7.8-11
• normal <7.8
• impaired fasting glucose <7.8

Question 14

RPG values

Answer 14

• diabetes = ≥11.1mmol/L

- normal = ≤ 7.8

Question 15

HbA1c values

Answer 15

diabetes = ≥ 48mmol/mol or 6.5%

• normal <42/5.9%%
• impaired glucose tolerance 4.2-4.7 (6-6.4)

Question 16

Type 1 and 2 differences

Answer 16

Type 1
- ketosis prone 
- insulin deficient
- autoimmune (GAD and ICA antibodies)
- acute onset
- non obese
- juvenile onset <35 yrs
- HLA DR3 and DR4
- FH positive in 10%
- 50% concordance in monozygotic twins
Type 2
- non ketosis prone
- insulin resistance and or deficiency
- non autoimmune as metabolic link
- insidious onset
- obesity associated
- >35 years but common below this age
- no HLA relation
- FH positive in 30%
- 100% concordance in monozygotic twins

Question 17

2ndry causes of diabetes

Answer 17

• pancreatic disease
• endocrine disease
• drug induced
• genetic defects of B cell function
• genetic defect of insulin action
• infections
• genetic syndromes
• gestational diabetes

Question 18

Pancreas exocrine causes of diabetes

Answer 18

• pancreatitis
• trauma/pancreatectomy
• neoplasia
• CF
• haemochromatosis/thalassaemia
• fibrocalculous pancreatopathy

Question 19

Endocrine diseases causing 2ndry diabetes

Answer 19

• acromegaly (GH)
• Cushing’s (cortisol)
• Glucagonoma (glucagon)
• Phaechromocytoma (catecholamines)
• Hyperthyroidism (thyroid hormone)
• Conn’s (aldosterone)

Question 20

Drugs inducing diabetes

Answer 20

• glucocorticoids
• Beta blockers
• thiazide diuretics
• tacrolimus (= NODAT)
• atypical antipsychotics = olanzapine, risperidone, clozapine

Question 21

Infections causing diabetes

Answer 21

Congenital rubella

CMV

Question 22

Pathogenesis of type 2 diabetes

Answer 22

• heterogenous
• environ = obesity, poor physical activity
• diabetogenic = genes contributing
• various combos of insulin resistance and beta cell failure
• exacerbated by hyperglycaemia = glucose toxicity as poorer B cell function so reduced insulin secretion so lowering glucose may help B cell function
• pro-inflammatory cytokines from adipocytes contribute from adipocytes contribute to resistance
• no autoimmunity
• B cell mass relatively preserved
• alpha cell population increased so excess glucagon relative to insulin
• post receptor insulin resistance
• late in disease = amyloid peptide deposition in pancreatic islets so dementia link

Question 23

Metabolic syndrome

Answer 23

• central obesity (waist circumference increased)
• bp abnormalities
• glucose abnormalities
• lipid abnormalities

Question 24

Who should be screened?

Answer 24

• obese/overweight
• strong FH
• history of gestational diabetes
• south Asian x 6 increased risk
• Afro-Caribbean x 2 increased risk
• known vascular disease (CHD, PVD, cerebrovascular disease)
• patients on steroids/atypical anti-psychotic therapy/transplants
• unexplained foot ulcers/recurrent candida/skin abscesses

Question 25

Aetiology of T1D?

Answer 25

• pancreatic B cell destruction
• leads to absolute insulin deficiency
• autoimmune destruction of pancreatic islets (ICA and GAD antibodies positive)
• may be antibody negative/idiopathic

Question 26

LADA

Answer 26

• latent autoimmune diabetes in aduts =
• diagnosed in adulthood
• non acute
• ICA or GAD positive
• require insulin fairly soon after diagnosis
• concordance in monozygotic twins
• environ factors = 5-7 years, puberty, seasonal variations, europid populations