16. Type 1 Diabetes Flashcards
epidemiology
0.5% prevalence
peak onset in adolescence
white caucasian
more prevalent in Northern latitudes
genetic predisposition
1-2% if mother affected
3-6% if father affected
6% if sibling affected
36% if monozygotic twin affected
association with HLA antigens
HLA DR3-DQ2 and DR4-DQ8 predispose
90% Scandinavians with T1 diabetes are positive for 1 or both
pathophysiology
beta-cell events trigger autoimmune response
antibodies to insulin of GAD generally appear first
other beta-cell antibodies follow (IA2, Zn2+ transporter 8)
selective immune beta-cell destruction
insulinitis
autoimmune destruction of pancreatic islet cells
schematic evolution of type 1 diabetes
genetic predisposition, environmental trigger causes insulinitis
as beta cell mass decreases, diabetes develops
autoimmune trigger of type 1 diabetes?
viral infection
ER (endothelial reticulum) stress
cytokines
associations with type 1 diabetes
coeliac disease hypothyroidism Grave's disease Addison's disease hypogonadism pernicious anaemia vitiligo autoimmune polyglandualr syndromes
symptoms fo type 1 diabetes
lethargy polyuria polydipsia blurred vision candida infections weight loss ketosis/ketoacidosis death
diagnosis of type 1 diabetes
age of onset rapidity of onset then type weight loss ketosis GAD/IA2/Zn2+ transporte 8 antibody positive c-peptide
what is c-peptide?
proceed in 1:1 molar ratio with insulin
needs adequate stimulus for secretion
insulin
necessary for survival
peptide hormone: must be given parenterally
typical insulin regimen
basal bolus regimen: rapid acting insulin pre-meal
long acting background insulin (basal)
balanced
rapid acting insulin reflects CHO intake
factors affecting blood glucose
diet injection site temperature exercise illness, stress alcohol menstrual cycle
hypoglycaemia
autonomic symptoms - palpitations, sweating, tremor
neuroglycopaenic symptoms - confusion
mild and severe
loss of warning signs
