Endocrinology Session 2 CLINICAL Flashcards
What is diabetes?
When blood glucose is too high (hyperglycaemia) and over the years, leads to damage of small and large blood vessels causing premature death from cardiovascular diseases.
What caused an epidemic in diabetes?
Environment (obesity, reduced activity)
- Not necessarily genetics
What is the pathophysiology of diabetes?*
- Food is broken down into glucose
- Rising blood glucose signals the pancreas to start releasing insulin
- Insulin binds to a place on the cell wall/insulin receptor
- Unlocks the cell so that glucose can enter the cell
- Most glucose used immediately
What are pancreatic islet cells?*
- Endocrine cells in pancreas
- Responsible for glucagon and insulin production (blood glucose control)
What are the 2 reasons for rises in blood glucose?
- Inability to produce insulin (beta cell failure)
- Insulin production is adequate but insulin resistance prevents insulin working effectively (linked to obesity)
What is the normal range for blood glucose?
3.9-7.1 mmol/L
What causes type 1 diabetes?
AUTOIMMUNE BETA CELL DESTRUCTION
- Autoantibodies made against beta cells
- Cells destroyed
- Absolute insulin deficiency (not enough insulin)
What causes T1 diabetes?
- Genetic predisposition (HLA-DQB1)
- Environmental trigger and genetic susceptibility combined
What causes type 2 diabetes?
- Pancreas may not produce enough insulin
- Cells may not be able to use insulin to unlock the cells and allow glucose to enter (resistance)
What is the presentation of diabetes mellitus (above 10 mmol/L)?
- Polyuria
- Polydipsia
- Blurring vision
- Urogenital infections
- Dehydration
- Lethargy and weakness
- Weight loss
How is diabetes diagnosed?
- Fasting glucose test
- Oral glucose tolerance test
- HbA1c (glycosylated haemoglobin test)
What is needed to diagnose diabetes?
- Symptomatic: 1 abnormal test
- Asymptomatic: 2 abnormal tests
What is the potential aetiology of type 1 diabetes?
- Twin studies (higher risk if sibling has it)
- Hygiene hypothesis - immature immune system produces antibodies against own cells accidentally
When is T1 diabetes most commonly diagnosed?
90% under 30 years of age, but can occur at any time. 1
What is the presentation of type 1 diabetes?
PATIENT:
- Usually young
- Ketone presence
SYMPTOMS:
- Rapid onset weight loss, polyuria and polydipsia
- Ketoacidosis when late presentation
How is type 1 diabetes treated?
- Exogenous insulin the only treatment
- Started immediately
- Given by subcutaneous injection several times a day
Why are ketones important in diabetes?
- Insulin suppresses the production of ketones, unless in starvation
- Activated in absence of insulin
- Presence indicates immediate need for insulin therapy
What are ketones?
Breakdown products of free fatty acid metabolism
acetone, acetoacetic acid and 3-beta-hydroxybutarate
What is ketoacidosis?
A life threatening condition requiring immediate treatment and hospitalisation. Characterised by hyperglycaemia and ketonaemia, which leads to acidosis.
What causes ketoacidosis?
Enhanced lipolysis
How is ketoacidosis diagnosed?
- Ketonaemia >3.0 mmol/L or significant ketonuria (2+ on standard urine sticks)1
What are some statistics about type 2 diabetes?
- 90% of sufferers are overweight or obese
- Many are asymptomatic and diagnosis made
- Managed by diet and tablets
- Most 40+ but increasing prevalence in children
What causes the development of insulin resistance?
- Central obesity (85%)
- Fat deposition in muscle and liver
- High circulating free fatty acids
- Physical inactivity
- Genetic influences
What happens after gastric bypass surgery?
- Glucose metabolism normalises
- No longer in diabetic range 1-2 weeks post-surgery
- Normalises even before any weight loss
- Fall in liver fat content
- Return to NORMAL insulin sensitivity
