t2dm Flashcards
symptoms
due to a slowly rising glucose:
• Tiredness, lethargy
• Polyuria and polydipsia = nocturia = poorly sleep = feel tired
• Often drink sugary drinks because of thirsty and tired – cause glucose to rise slowly
• Normal glucose 5.5
• When 10 – reach renal threshold – polyuric and polydipsia
• With other co-morbidities it becomes difficult to drink enough
• Osmotic diuresis causes loss of water and a rise in Na
• Eventually glucose really high, as is the sodium
• Polyuria – takes sugar out, water leaves by osmosis = high Na left = hyperosmolar – insidious
osmolatity calculation
osomolarity = cations (Na+K) + anions (Cl + Bicarb) + glucose + urea
cant measure the other ions - but you cant be charged - so just double cations instead:
osmolarity = 2(cations) + glucose + urea
Na + K = 144
problem with being really hyperosmolar
at 430mM - start pulling water out of the brain = confused
might present with a stroke - made worse by the really high glucose
describe the insidious onset of t2dm
people spend months to years not knowing they have it
have hyperglycaemia but no dm
intermittent polyuria and dipsia – assumed to be prostate trouble or water work infections – don’t come to dr
Hyperglycaemia – slowly damages the endothelium = micro and macrovascular complications
MI in dm – because neuropathy, you don’t feel the pain and then go to HF
microvascular complications
glycosylation of bm proteins = leaky cap =
retinopathy
nephropathy
neuropathy
macrovascular complications
dyslipidaemia, HTN, hypercholosteraemia =
IHD
CVA
peripheral gangrene
summarise retinopathy
Background diabetic retinopathy - Hard exudates (deposits of cholesterol) and blot haemorrhages, microaneurysms (little red dots) . Macular is preserved
Cotton woll spots mean ischemia – means hypoxia in cells in this area. Anywhere else get pain on hypoxia, advice people to walk etc to get collaterals. In eye - bad because new vessels thin and can bleed so if bleed = permenant blind – this is pre-proliferative
proliferative - Tiny new vessels – one cell between vitreous and vessel = blind
treatment for retinopathy
Treatment for background diabetic retinopathy – improve blood glucose control to prevent vision changing
Pre-proliferative: need pan retinal photocoagulation (laser treatment) destroy some of the periphery. Deliberately kill off part of the eye in order to maintain central vision – must keep macular. Can lose 1/3 periphery without problem
Little spots in periphery – if anything moving in periphery can see it because it catches part of the periphery that is fine. Preserve the middle bit, eyes not better though
is there evidence glycaemic control prevents complications
yes - intensive control from new diagnosis helps outcomes at 15 yrs - but no improvement before then
if stop intensive control - pts control returns to that of non-intervention
but have legacy effect - any end point stay better - benefits they had in the 1st 15yrs are lasting
summarise findings of the accordand MI and die – coronary arteries already damaged, cant undo study
Randomised people to either have tight control at this point, using their drug? Said that if you want to prove benefit – need to take people already had MI because they’re likely to have another. This reduced the risk of stroke and MI, but more deaths in the intensively controlled people. Actual death rate went up – people had sudden death, because of previous MI – identify a previously unrecognised harm of intensive… cant take people with ischemic and tighten. Because get more hypo, and hypo in IHD = VF
therefore in elderly give less aggressive treatment
drug class of metformin
biguanide
DCCT trial
type 1 dm
good control improves outcomes
incretins
GLP1 analogues
proteins that stimulate the production of insulin
gliptins
dipeptidyl peptidase 4 inhibitors – inhibit thing that breaks down your own GLP1
insulin
- Excellent drug even when people are not dependant on it (NIDDM)
- Need a long acting depot insulin eg zinc suspension - Insulatard
- Short acting insulin eg normal soluble insulin just before meal - actrapid
problem with insulin
when given subcut - the A and B chains stick to each other = delayed release - therefore need to have half an hour before meal
insulin analogues
lispro - switch the 2 aa on end of B chain - proline with lysine = make the insulin act much more rapidly
aspart - swith proline to Aspartate
act much quicker which means the pt can inject when they eat
profile mimics insulin profile of insulin following a meal
expensive
long acting insulin analogues
different alterations in the molecule to try and attain a plateau conc over time
o Glargine – A chain – add arginine, make sticky so last longer = less chance of hypoglycaemia
insulin detemir - 14C FA chain attached to B29, delayed onset
gives background concentration of insulin like pancreas
previous pong acting insulins were zn suspension of insulin - efficacy waned over 24hr
advantages of insulin
can give best control of Hba1c when compared to diet and exercise
no SE when compared to metfromin (diarrhoea), sulphonylureas (occaisional skin reactions), thiazolidinediones (rare hepatic, ?osteoporosis)
disadvantages of insulin
o If you drive HGV – cant work
o Exenatide exempt
o Hypoglycaemia common with good control – less MI but cant drive
o Weight gain because insulin make you hungry
If glucosuria stops calories saved = increased appetite
o Increased insulin as a consequence
o High doses needed
why weight gain with insulin
if glucosuria stops = many calories retained increased appetite improved wellbeing set point of body weight (hypothalamic) poor control enables weight loss
GLP-1 analogues
gut males GLP1, signals panc to make insulin and reduce glucagon
has a direct effect on gastric emptying and appetite = increase hypothalamic satiety
exanatide
incretins
extendin 4 from Gila monster venom - similar in structure to GLP-1 but longer t1/2
exenatide - sythetic version - injection
increase hypothalamic satiety
liraglutide (victoza or saxenda) semaglutide
gliptins
vildagliptin and sitagliptin
ie DPP4 inhibitors