DIABETES MELLITUS Type I&II DKA, HHS Flashcards
What is diabetes?
Diabetes is defined as an elevation of blood glucose above a diagnostic threshold.
Name some pure genetic disorders associated with insulin action.
Donohue syndrome, Rabson-Mendenhall syndrome
What conditions feature insulin resistance?
Obesity, Type 2 diabetes, NAFLD
List some endocrinopathies associated with insulin resistance.
Cushing’s syndrome, Acromegaly, Phaeochromocytoma, Glucagonoma
What is a common cause of insulin resistance induced by external factors?
Steroid-induced, specifically by exogenous glucocorticoids
What are the disorders associated with insulin secretion?
Type I diabetes, MODY, Neonatal diabetes
Name some genetic disorders related to insulin secretion.
MODY, Neonatal diabetes
What are some pancreatic diseases associated with insulin secretion?
Alcoholic and chronic pancreatitis, Acute pancreatitis, Pancreatectomy, Pancreatic cancer, Cystic fibrosis, Haemochromatosis
What is the spectrum of Type 2 diabetes in terms of insulin deficiency and resistance?
Ranging from predominant beta cell deficiency to predominant insulin resistance
Is diabetes often asymptomatic?
Yes, especially type 2 diabetes.
What are the symptoms of high blood glucose?
Polyuria,
Thirst and polydipsia,
Blurred vision,
Genital thrush,
Fatigue,
Polyphagia Weight loss
Why does hyperglycemia cause blurred vision?
Hyperglycemia results in changes to osmotic pressures in the anterior chamber of the eye in front of the lens.
Name some diabetic emergencies and their associations.
Diabetic ketoacidosis (most commonly due to type 1), Hyperosmolar hyperglycaemic state (extreme presentation of new type 2 diabetes)
When might complications of diabetes present with symptoms/signs?
Rarely, and they may include loss of vision, retinal bleed, or retinal changes found by an optician.
What is the purpose of the C-peptide measurement?
C-peptide, co-secreted with insulin, is used to measure ‘endogenous’ insulin secretion. If present, it indicates secretion by the person’s beta cells.
How does HbA1c provide information about glucose exposure?
HbA1c reflects the amount of glycation of hemoglobin, which is proportional to glucose exposure over the last 90 days. It is used in diagnosis and monitoring of diabetes.
What caution is advised when interpreting HbA1c results?
Caution is needed in conditions of increased or reduced RBC turnover, such as haemolytic anaemia.
What are the diagnostic criteria for diabetes based on fasting glucose?
Fasting glucose ≥ 7.0 mmol/L is considered diagnostic for diabetes.
In gestational diabetes, how are threshold levels determined?
In gestational diabetes, threshold levels are not set by retinopathy risk but rather by risk to the fetus/neonate, and are much lower.
What are the three diagnostic criteria for diabetes?
Fasting glucose ≥ 7 mmol/L, Random or 2 hr (after 75g oral glucose) glucose ≥ 11.1 mmol/L, HbA1c ≥ 48 mmol/mol. If asymptomatic, a repeat confirmatory test is required.
Define ‘Normal glucose tolerance’ in terms of fasting glucose, 2hr glucose in OGTT, random glucose, and HbA1c.
Fasting glucose ≤ 6.0 mmol/L, 2hr glucose in OGTT ≤ 7.7 mmol/L, Random glucose ≤ 7.7 mmol/L, HbA1c ≤ 41 mmol/mol.
What are microvascular complications of diabetes?
Retinopathy, neuropathy.
What is the recommended HbA1c target for preventing microvascular complications?
Aim for HbA1c <53 mmol/mol to prevent microvascular complications.
Name some macrovascular complications of diabetes.
MI/ACS (Myocardial Infarction/Acute Coronary Syndrome), stroke, PVD (Peripheral Vascular Disease).
What preventive measures are recommended for macrovascular complications?
Cholesterol control, blood pressure control, antiplatelet therapy.
Besides blood glucose, what other complications should be screened for in diabetes management?
Eye disease (laser), Neuropathy (podiatry), Kidney disease (BP management, ACEi).
What is the primary cause of Type 1 diabetes?
Autoimmune destruction of pancreatic beta-cells, resulting in beta-cell deficiency and absolute insulin deficiency.
What are the two subtypes of Type 1 diabetes?
Type 1A (immune-mediated) and Type 1B (non-immune mediated).
What characterizes Type 1A diabetes?
It involves an environmental trigger in a genetically susceptible individual, mediated by an autoimmune process within the pancreatic β-cell.
What is LADA, and when does it typically occur?
LADA (Latent Autoimmune Disease in Adults) is a ‘slow-burning’ variant of Type 1A with slower progression to insulin deficiency, occurring in later life.
What characterizes Type 1B diabetes?
It involves patients with permanent insulinopenia, prone to DKA, but without evidence of β-cell dysfunction or autoantibodies.
What percentage of T1DM patients does Type 1B account for?
Approximately 5% of T1DM patients.
Which population is Type 1B more common in?
Type 1B is more common in individuals of African or Asian ancestry.
What are the risk factors for Type 1 diabetes in terms of age?
The peak incidence is in individuals under 20, with a smaller peak in the late 30s (LADA), and clinical presentation is possible at all ages up to the 9th decade.
How much of the familial risk of T1DM do HLA genes represent?
HLA genes represent approximately 50% of the familial risk of T1DM.
What are some high-risk HLA genotypes for T1DM?
DR3-DQ2 and DR4-DQ8 are high-risk HLA genotypes for T1DM.
What is the risk of offspring developing diabetes if both parents have susceptible HLA alleles?
The risk is 30%.
Besides HLA genes, what other genetic factors influence the risk of T1DM?
At least 47 non-HLA genes or gene regions influence the risk of T1DM to a minor extent.
What are some environmental factors associated with the risk of Type 1 diabetes?
Maternal factors (gestational infection and older age), viral infections (e.g., Coxsackie B4), dietary constituents (early introduction to cow’s milk, vitamin D deficiency), environmental toxins (e.g., alloxan), childhood obesity, and psychological stress.