T1DM Flashcards
define Type 1 Diabetes
A state of absolute insulin deficiency
In all probability caused by an environmental trigger
in a genetically susceptible individual mediated for
the most part by an auto-immune process of varying
degree of severity occurring within the pancreatic
β cell
Risk Factors for Development of T1D (5)
Age- 85% of DM in under 20s, peak 10-14yrs and 25% diagnosed as adults- all ages upto 9th decade
Sex- M=F in young, differences in European popn M>F in after puberty
Race- SEARCH Us database. Other data heterogenous- NHW>AA>Hispanic>API>Navajo
Genotype- HLA complex chromosome -HLA class II. 40–50% familial
Geographic location & Seasonality- excess in winter month births, in other countries similar in northern latitudes but different in southern
HLA association (4)
HLA genes represent ~50% of familial risk of T1DM
Highest risk genotype [DR3-DQ2/DR4-DQ8] confers ~19-
fold increase risk
95% of those with T1DM diagnosed under 30 have one
or both of the genotypes
Non-HLA – at least 47 factors identified.
Enviromental triggers (4)
→Viral infection
→Maternal factors
→Weight gain
→Vitamin D
Normal glucose/ insulin physiology (2)
Insulin is secreted at a low basal rate which accounts for about 50% of insulin produced
Post-prandial insulin is secreted in relation to post-meal glucose
Insulitis
– lymphocytic inflitrate
presenting symptoms triad! (3)
Polyuria- pee
- Enuresis in children
Polydipsia- thirst
Weight loss
presenting symptoms (5)
Fatigue and somnolence
Blurred vision
Candidal infection
Pruritis vulvae
Balanitis
diagnosing diabetes (3)
Fasting glucose ≥ 7.0mmol/l
Random ≥ 11.1mmol/l
and symptoms, OR repeat test
diagnosing which type (2)
Often Type 1 diabetes is diagnosed on the history and presentation (e.g. DKA) alone
If in doubt, IC antibodies [and C-peptide] may help
