Diabetes Mellitus Flashcards
What are the normal actions of insulin?
- Increase glucose uptake
- Increase glycolysis
- Decrease gluconeogenesis
- Increased protein synthesis and decrease protein breakdown.
- Fat deposited in adipose tissues
- Ketogenesis decreased
What are the ‘anti-insulin’ hormones?
- Glucagon
- Adrenaline
- Cortisol
- Growth hormone
What are the early changes in carbohydrate metabolism seen in DM?
Earliest abnormality = increased blood glucose after ingesting carbohydrates.
Early on, the feedback loop between glucose and insulin able to maintain normal fasting glucose.
With worsening insulin action, fasting hyperglycaemia develops <— biochemical hallmark of DM.
In what circumstances is hypoglycaemia seen?
- Excessive insulin given to treat DM
- Excessive insulin secretion from pancreatic tumour or from sulphonylurea therapy.
- Under-production of anti-insulin hormones eg hypoadrenalism/hypopituitarism
- Starvation or liver disease, in which glycogen stores depleted and/or gluconeogenesis fails.
Why is the process of glycation important?
- Damages tissues and is one of the processes causing diabetic complications.
- Measuring degree of glycation gives time-averaged measure of hyperglycaemia (HbA1c)
What symptoms are seen in DM?
- Can be asymptomatic
- Thirst, polyuria, polydipsia
- Blurred vision
- Lethargy and somnolence
- Weight less and weakness
- Balanitis (swelling of head of penis)
- Anorexia and nausea
- Pruritis valvulae (itch of vulvula)
- Recurrent skin infections
What is the presentation of severe hyperglycaemia?
- Severe thirst
- Drowsiness/coma
- Vomiting
What is the investigation protocol for DM?
If symptomatic, single plasma glucose measurement that is raised according to WHO criteria = diagnostic.
If asymptomatic, 2 abnormal blood glucose concentrations needed, on two separate days (Fasting glucose best)
What is impaired glucose tolerance and what are the diagnostic values?
Fasting blood glucose normal but abnormally increased after oral glucose.
Fasting plasma glucose <11.1mmol/L
What is the WHO diagnostic criteria for DM?
- Random venous plasma glucose conc ≥11.1mmol/L OR
- Fasting plasma glucose conc ≥ 7.0 OR
- Plasma glucose conc ≥11.1 2 hours after 75g glucose
What are the diagnostic values for impaired fasting glycaemia?
Fasting plasma glucose >6.1 but <7.0mmol/L
What is the treatment for type 1 DM?
Insulin replacement
What are the oral treatment options for type 2 DM?
- Biguanides (metformin) - Decreases hepatic gluconeogenesis
- Sulphonylureas (gliclazide) - increases insulin secretion
- α-glucosidase inhibitors (acarbose) - inhibit intestinal brush border saccharidases and delays glucose absorption.
- Meglitinides (natiglinide) - enhance meal related insulin secretion.
Why is metformin first line oral therapy?
Metformin does not increase insulin secretion therefore does not cause weight gain.
In which patients is metformin contraindicated and why?
Renal failure, heart failure and liver disease
It can cause lactic acidosis.
