T1DM Flashcards
Definition of T1DM
Type 1 diabetes mellitus is a metabolic disorder characterised by hyperglycaemia due to absolute insulin deficiency.
Aetiology of insulin deficiency in T1DM
Destruction of pancreatic beta cells, mostly by immune-mediated mechanisms.
What are the HLA polymorphisms that predispose to T1DM?
HLA-DR and HLA-DQ
What are the autoantibodies that are usually positive in T1DM?
glutamic acid decarboxylase;
insulin;
islet auto-antigen-2 (IA-2)
What is the type of acidosis present in DKA?
Anion gap metabolic acidosis
Triad in T1DM
Fatigue, polyuria and polydipsia
What features suggest LADA (Latent autoimmune diabetes in adults) rather than T2DM?
Age of onset <50 years, acute symptoms
body mass index less than 25 kg/m² personal or family history of autoimmune disease
When should you measure C-peptide to distinguish between T1 and T2 diabetes?
If there is difficulty distinguishing type 1 diabetes from other types
On diagnosis where must you refer a patient with T1DM?
Local eye screening services
1st line investigations to diagnose T1DM in children
Random plasma glucose >11.1mmol/L
Fasting plasma glucose >7.0 mmol/L
OGTT (2 hour plasma glucose) >11.1 mmol/L
HbA1c >48mmol/L or 6.5%
How do you diagnose T1DM in adults?
Clinical diagnosis
Usually: hyperglycaemia +
ketosis, rapid weight loss, age <50 years, BMI <25 kg/m², personal and/or family history of autoimmune disease
How much is the glucose load in an OGTT?
75g of oral glucose
Plasma glucose targets: fasting, before meals and 90min after a meal
Fasting: 5-7 mmol/L
Before meals: 4-7 mmol/L
90 min after meal: 5-9 mmol/L
what is a basal-bolus insulin regime?
Long-acting insulin twice a day before breakfast and before bed
Short-acting insulin before meals
Long-acting insulin types
detemir (Levemir) 18 hr half-life
degludec (Tresiba) 25hr half-life
glargine (Lantus) 12 hr half-life
