Diabetes Flashcards
What is the definition of diabetes?
Symptoms and random plasma glucose > 11 mmol/l
Fasting plasma glucose > 7 mmol/l
No symptoms - GTT (75g glucose) fasting > 7 or 2h value > 11 mmol/l
HbA1c (glycated Hb) is now used in diagnosis.
What are the presenting features of diabetes?
Polyuria and polydipsia (thirst) - osmotic diuresis and activation of hypothalamus.
Weight loss and fatigue - impaired glucose utilisation.
Pruritis vulvae and balanitis
Hunger - lack of insulin preventing hypothalamic glucose uptake
Blurred vision - altered acuity due to uptake of glucose into lens
What is the prevelance of TIDM?
0.3%
What are the three clinical features of newly diagnosed type 1 diabetes?
Weight loss, short history and moderate - large urinary ketones
What are the aims of treatment for type 1 diabetes?
Relief of symptoms, prevention of ketoacidosis, prevention of complications (micro and macrovascular).
What are the microvascular complications of diabetes?
Retinopathy, neuropathy and nephropathy (U&Es and urine test for microalbumin).
What percentage of people with diabates in the UK will develop diabetic nephropathy?
30%
x30 risk of mortality
Tendency to develop retinopathy and neuropathy too.
Describe insulin treatment for diabetes.
- Twice daily mixture of short/medium acting insulin
- Basal bolus (1-2 daily medium acting plus pre-meal quick-acting)
What causes hypoglycemia in type 1 diabetes?
Innapropriately high insulin levels.
What percentage of people with type 1 diabetes experience hypoglycaemia?
30%
What percentage of people with type 1 diabetes will have severe hyperglycaemia once per year?
10%
What percentage of type 1 patients will have a blood glucose of 3.5 mmol/L on any given night?
50%
Why is hyperglycaemia a medical emergency?
Cerebral tissue uses glucose for fuel. Interruption of supply produces instant changes.
What signs are produced by a plasma glucose of 2mmol/L?
Abnormal EEG and confusion
What signs are produced by a plasma glucose of 1 mmol/L?
Coma and seizures.
What signs are produced by a plasma glucose of < 1 mmol/L?
If prolonged - irreversible cerebral damage.
What are the physiological protections counterregulatory hormones?
Adrenaline and glucagon - both increase hepatic glucose output.
What are the autonomic signs and symtoms of hypoglycaemia?
Nausea, tremor, sweating, tachycardia, pallor and anxiety (adrenergic).
What are the neuroglycopenic signs and symptoms of hyperglycaemia?
Confusion, drowsiness, lethargy, lack of concentration , slurred speech, aggression and coma.
What are the risks associated with the avoidance of hypoglycaemia?
Increases the risk of diabetic complications.
What proportion of patients can expect a reasonable life expectancy in diabetes?
2/3
What are the consequences of insulin resistance in type 2 diabetes?
Decreased insulin-dependent glucose uptake into muscle and adipose tissue.
Combined with excessive glucose production by the liver, this leads to hyperglycaemia, which in turn causes a compensatory increase in insulin secretion.
As diabetes becomes more severe the insulin response becomes progressively impaired due to pancreatic exhaustion.
What are the complications of type 2 diabetes?
Blindness, ESKD, CVD, CVA and amputations.
By how much is one’s life expectancy shortened at diagnosis of type 2 diabetes?
10 years
What are the standard initial treatments in type 2 diabetes?
Weight loss and exercise
How do thiazolidinediones (e.g. rosiglitazone) work?
Decrease insulin resistance in adipose tissue, skeletal muscle and liver.
They may have a beneficial effect on b-cell function.
Direct insulin sensitizers that act as agonists for the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARg). PPARg increases the transcription of certain insulin-sensitive genes, thereby improving insulin sensitivity.
How do biguanides such as metformin work?
Primarily suppress hepatic glucose output. In addition, they enhance insulin sensitivity and stimulate insulin-mediated glucose disposal. They do not stimulate insulin secretion.
How do the sulphonylureas and meglitinides work?
Both lower fasting blood glucose concentrations, primarily by stimulating insulin secretion from the pancreas.
How do alpha-glucosidase inhibitors such as acarbose work?
Delay digestion and absorption of carbohydrates in the gastrointestinal tract. They inhibit the enzyme a-glucosidase, responsible for the metabolism of complex carbohydrates into absorbable monosaccharides.
How do glucagon-like peptide 1 (GLP-1) analogues work?
Mimic GLP-1, a gastrointestinal hormone that increases insulin secretion from the pancreas and inhibits glucagon release.
How do dipeptidyl peptidase 4 (DPP-4) inhibitors work?
Block the DPP-4 enzyme which would otherwise inactivate GLP-1.
What is the triangle approach to diabetes management?
- Improve glucose levels
- Avoid hypoglycaemia
- Limit glucose variability
