diabetes Mgx (see DM) Flashcards
what is diabetes mellitus
a metabolic disorder characterised by chronic hyperglycaemia due to defects in insulin secretion/action
4 actions of insulin in the body
- increases glycogenesis
- increased peripheral glucose uptake
- inhibition of hepatic glucose production
- inhibition of lipogenesis/lipolysis
4 drug classes that can induce diabetes
- steroids
- thiazides (e.g. diuretics for HF)
- anti-psychotics
- BBs
impaired fasting glucose test values
> 6.1mmol/L but <7.0mmol/L
impaired glucose tolerance test values
fasting <7.0mmol/L;
OGTT >7.8 but <11.0mmol/L
what type of hormone is insulin
a peptide hormone
what is the precursor molecule to insulin
preproinsulin
proinsulin -> insulin pathway (check this)
proinsulin -> cleaved by proprotein convertase (removes the middle C-peptide) -> carboxypeptidase -> insulin
what is the half life of insulin?
6 minutes
what are the 4 types of manufactured insulin doses and how long dose each last
short acting: 4-6 hrs
intermediate: 12-10hrs
long: 24hrs
mixed: comprises of short + intermedite acting
what are the blood glucose targets for T1 diabetes (3)
On waking: fasting blood glucose 5–7 mmol/L;
Before meals: blood glucose 4–7 mmol/L;
Post meals: test after 90 minutes, blood glucose 5–9 mmol/L;
what is HbA1c
glycated haemoglobin - average blood glucose (sugar) levels for the last two to three months; Glycated haemoglobin occurs due to non-enzymatic irreversible modification of the beta globin chain in haemoglobin
what is the “honeymoon period” (T1 diabetes)
The honeymoon period can occur in newly diagnosed patients in whom there is residual beta cell function -> This may negate the need for exogenous insulin for a period
what are diabetes sick day rules (5)
a number of recommendations in T1DM with an intercurrent illness. Advice includes:
1. Continue insulin therapy, alterations may be required, advice from a specialist may be sought;
2. Increase frequency of blood glucose monitoring;
3. Consider ketone monitoring;
4. Maintain good hydration and when possible a normal meal pattern, meals may be replaced by carbohydrate based drinks;
5. Seek urgent medical attention if unable to tolerate oral intake, drowsy or sustained vomiting
why do diabetics often get foot complications
Due to loss of sensation and poor blood supply, patients are at risk of a number of complications including diabetic ulcers, secondary infection (e.g. cellulitis, osteomyelitis), skin necrosis and eventually amputation
what is charcot’s joint
complex neuropathic arthropathy that results from loss of sensation and subsequent repeated micro-trauma to the foot
what is the main macrovascular complication of diabetes
atherosclerosis
4 prophylactic measures to reduce CVD risk
- Smoking cessation
- Nutritional support & exercise
- Consideration of anti-lipid therapy (e.g. atorvastatin)
- Blood pressure control
what is the MOA of Sulphonylureas
block K+ Ch opening => cell membrane depol occurs leading to Ca2+ influx and thus insulin release
what amino acid increases the chance of beta-cell depol and why
Arganine, it is positively charged
metformin MOA (3)
- Metformin decreases blood glucose levels by decreasing hepatic glucose production (gluconeogenesis);
- decreases the intestinal absorption of glucose
- increases insulin sensitivity by increasing peripheral glucose uptake and utilization
2 side effects of sulphonylureas
- hypoglycaemia
- weigh gain (1-4kg in 6 months)
meglitinides MOA
insulin secretagogues -> stimulates the release of insulin from beta cells e.g. repalinide potentiates the effect of extracellular glucose on ATP-sensitive potassium channel (relies on there being some beta-cell function)
2 examples of meglitinides
- natiglinide
- repaglinide
