10. Diabetes Flashcards
(48 cards)
What is diabetes?
Metabolic disorder characterised by hyperglycaemia due to insulin deficiency, insulin resistance or both.
What is type 1 diabetes characterised by?
Progressive loss of all or most of the pancreatic beta cells due to autoimmune attack.
When is type 1 diabetes usually diagnosed?
Children and teenage years
How is type 1 diabetes treated?
Life-long insulin treatment (must be injected)
Dietary management and exercise also key components
What is the cause of hyperglycaemia in type 2 diabetes?
Progressive loss of beta cells along with disorders of insulin secretion and resistance.
When is type 2 diabetes usually diagnosed?
Older patients, may be present for a long time before diagnosed.
How is type 2 diabetes managed?
- Diet
- Oral hypoglycaemia drugs
- Eventually insulin as it progresses
List the classic triad of symptoms you would expect to see in a patient with Type 1 diabetes mellitus.
- Polyuria
- Polydipsia
- Weight loss
Why is polyuria a feature of diabetes?
Glucose levels exceed renal threshold, and some glucose is excreted. Less water is reabsorbed into the nephron to account for the increased osmotic load.
Why is polydipsia a feature of diabetes?
Excessive water loss from polyuria and osmotic effects of glucose on the thirst centre.
Why is weight loss a feature of type 1 diabetes?
Increased proteolysis and lipolysis
How is diabetes easily diagnosed?
Measuring plasma glucose levels
Urine ketone and glucose levels
What life threatening crisis can untreated type 1 diabetes lead to?
Diabetic ketoacidosis
What affect does insulin deficiency have on the metabolism?
Rapid lipolysis, excess FA converted to ketone bodies in the liver.
How can type 1 diabetes result in ketoacidosis?
Increased rate of lipolysis in adipose tissue which releases large amounts of fatty acids, the substrate for ketone body formation. H+ associated with the ketones produces a metabolic acidosis.
Activation of the ketogenic enzymes in the liver.
How can ketoacidosis be detected on the breath?
Acetone is a volatile ketone body that can be smelt on the patients breath
What are the symptoms of ketoacidosis?
Prostration - exhaustion Hyperventilation Nausea and vomiting Dehydration Abdo pain
Rather than the triad, which symptoms are patients with Type 2 diabetes more likely to be present with?
Lack of energy
Persistant infections (genital thrush)
Slow healing
Visual problems
If diet management fails, what oral hypoglycaemic drugs can be used to treat type 2 diabetes?
Sulphonylurea - increase insulin release from beta cells
Metformin - reduces gluconeogenesis
In which tissues is uptake of glucose determined purely by extracellular glucose concentration, what are the complications of this?
Peripheral nerves, eye and kidney.
During hyperglycaemia, the intracellular [glucose] increases and it metabolised by aldose reductase.
This reaction depletes NADH, increases disulphide bond formation in proteins, altering structure and function.
Accumulation of product sorbitol causes osmotic damage.
What changes to the plasma proteins occur in persistant hyperglycaemia?
Glycation of plasma proteins such as lipoproteins and haemoglobin.
How goes glycation of plasma proteins affect their function?
Forms stable covalent linkages, changing the charge and overall structure of the proteins, therefore affecting function.
What is HbA1c?
Glucose reacts with Hb to form glycated Hb.
How is HbA1c used clinically?
Percentage of Hb glycated is a good indicator of how effective glucose control has been.
