Diabetes Mellitus Flashcards
Define diabetes mellitus.
Diabetes mellitus is a metabolic disorder characterised by chronic hyperglycaemia due to defects in insulin secretion and/or insulin action.
How is diagnosis of diabetes confirmed in any person?
Hyperglycaemic symptoms (polyuria, polydipisa) with random or postprandial blood glucose more than or equal to 11.1mmol/L or fasting plasma glucose more than or equal to 7mmol/L
How is the oral glucose tolerance test (OGTT) used to diagnose diabetes?
Overnight fast (more than or equal to 8 hours) Fasting plasma glucose 75g anhydrous glucose to drink 2nd blood sample 2 hours later.
What are the WHO criteria (2006) for diagnosing patients in PRESENCE of symptoms? What about asymptomatic patients?
Random plasma glucose ≥ 11.1 mmol/L OR Fasting plasma glucose ≥ 7 mmol/L OR 2 hour plasma glucose ≥ 11.1 mmol/L 2 hours post 75g OGTT Asymptomatic - at least one of above confirmed on 2 seperate occassions.
What are the WHO criteria (2011) for diagnosing patients using HbA1c?
HbA1c ≥ 48mmol/mol (6.5%) with symptoms and plasma glucose ≥ 11.1 mmol/L Or HbA1c ≥ 48mmol/mol (6.5%) in asymptomatic.
In which patients should the HbA1c test not be used?
- Children/young people - T1DM - Pregnancy - Medications eg steroids that cause sudden increase in glucose - symptoms onset within 2 months - Genetic, haemaologic and illness factors that affect haemoglobin.
What does glycosylated haemoglobin reflect exactly?
Formed by glycation fo Hb as exposed to plasma. It reflects average plasma glucose over previous 8-12 weeks.
What is the difference between impaired fasting glycaemia /IFG and impaired glucose tolerance/IGT? What do you need to do in these groups of patients?
Impaired glucose tolerance/IGT = fasting plasma glucose <7 mol/L And 2 hour plasma glucose ≥ 7.8 but <11.1mmol/L on an OGTT Impaired fasting glycaemia /IFG = fasting plasma glucose 6.1-6.9 mmol/L Patients with either or both of above are at risk of diabetes - educate on lifestyle changes and monitor glucose with blood tests every 1-2 years.
which groups of patients should be offered screening for diabetes ?
- Overweight/obese - atherosclerotic disease - first-degree relative with Type II diabetes melitus - African Caribbean/Middle Eastern/South Asian origin - IFG and IGT - Woman who had gestational diabetes but tested normal following delivery - Obese women with polycystic ovary syndrome
What are the two ways of monitoring long-term control of diabetes?
- Hb1Ac 2. Fructosamine (if haemoglobulinopathies)
What are the two ways of monitoring short-term patterns in patients with diabetes?
- Blood capillary glucose using blood monitors > diary > reviewed by diabetic team 2. Continuous glucose monitoring.
What is continuous glucose monitoring?
A device the displaced subcutaneously and worn from 24 hours to several days to note patterns in blood glucose variation.
Why is continuous glucose monitoring useful?
In patients who have problematic control it helps to alter insulin doses or settings of these on insulin pump therapy.
Aside from type one and type two diabetes give other causes for development of diabetes.
- Endocrine disorders such as acromegaly, Cushing’s syndrome, glucagonoma (excess GH, cortisol and glucagon antagonise insulin) - Drugs eg steroids increase gluconeogenesis and increase insulin resistance - Gestational diabetes - genetic defects in beta-cell function, e.g. maturity onset diabetes of the young, neonatal diabetes - genetic defects in insulin action e.g. type A insulin resistance - Pancreatic diseases eg chronic pancreatitis, infection, trauma, cystic fibrosis - damage the pancreas. - other syndromes eg Turner’s, Down’s Kleinfelter’s
What is the main difference between type I and type II diabetes?
Type I - 5-10% of diabetes. Cellular mediated process causing destruction of beta cells of pancreas causing an absolute insulin deficiency. Type II - 95-90% diabetes. Associated with obesity, caused by both insulin resistance and defect in insulin secretion. In both cases genetic predisposition plays a part (more so in Type II diabetes, but it is also polygenic and more difficult to understand). In type I diabetes environmental factors also play a part.
Name at least three potential environmental triggers for T1DM.
- Chemicals viruses e.g. rubella - bacteria - intrauterine factors e.g. pre-eclampsia, birth weight - Diet (vit D deficiency) - Stress