Type 1 diabetes - clinical features and pathophysiology Flashcards
What is the definition of type 1 diabetes?
A state of absolute insulin deficiency
In all probability caused by an environmental triger in a genetically susceptible individual mediated for the most part by an auto-immune process of varying degree of severity occuring within the pancreatic beta cell
What is the diagnostic critera for type 1 diabetes?
Fasting glucose > 7.0 mmol/l
Random >11.1 mmol/l
Symptoms of hyperglycaemia or repeat test
What autoantibodies can be present in T1DM?
GAD
IA2
IAA
ZnT8
What is the risk of developing T1DM if both parents have it?
30%
What is the risk of developing T1DM if the father has it?
8%
What is the risk of developing T1DM if the mother has it?
3%
What HLA genes are associated with T1DM?
DR3-DQ2
DR4-DQ8
What environmental factors can trigger T1DM?
Observations - seasonality Timing of birth Viral infection Maternal factors Weight gain
If you have GAD antibodies what is the risk of having T1DM?
70-80%
If you have IA2 antibodies what is the risk of having T1DM?
60-70%
What maternal factors can increase the risk of developing T1DM?
Infection Age ABO mismatch Birth order Stress
What are common autoimmune trigger factors for developing T1DM?
Viral infection
Vitamin D deficiency
Dietary factors
Environmental toxins
What disease markers are present in the autoimmune process?
Autoantibodies (GAD, IAA, IA2, ZnT8)
Candidate antigens
Insulitis
What clinical features are present in clinical diabetes?
Hyperglycaemia Ketones Decreased insulin Decreased beta cell mass Decreased C-peptide
What are risk factors for clinical diabetes?
Infection Insulin resistance Puberty Diet/ weight Stress
What are the typical presenting symptoms of T1DM?
Polyuria Polydipsia Weight loss Fatigue and somnolence Blurred vision Candidal infection - pruritus vulvae, balantitis Keto-acidosis
What is included in the management of a newly diagnosed patient with T1DM?
Blood glucose and ketone monitoring Insulin: basal and bolus Carbohydrate estimation Regular DSN and dietitican contact Appropriate medical clinical review Regular HbA1c (48-58 mmol/mol)
What should be included in an annual review assessment?
Weight BP Bloods: HbA1c, renal function, lipids) Retinal screening Foot risk assessment
What are the different type of diabetes included within T1DM?
NND
MODY
LADA
Secondary diabetes
What is normal insulin secretion?
Biphasic secretion in response to meal - rapid phase of pre-formed insulin that lasts for 5-10 mins
Slow phase over 1/2 hours
Where does insulin go after it is released from the pancreas?
Portal vein
What is neonatal diabetes?
Children diagnosed under the age of 6 months are much more likely to have monogenic rather than T1DM
What is LADA?
A diagnosis of LADA is established by the presence of elevated levels of pancreatic auto-antibodies in patients with recently diagnosed diabetes who do not initially require insulin
When should LADA be suspected?
Occurs in YA 25-40 Male preponderance Non-obese Auto-antibody positive Associated auto-immune conditions Non-insulin requiring at diagnosis Sub-optimal control on oral agents
