diabetes and hypoglycaemia Flashcards
(25 cards)
describe blood glucose/homeostasis
glucose major energy substrate
levels maintained by:
- dietary carbohydrates
- glycogenolysis
- gluconeogenesis
describe fed state
increased plasma glucose = increased insulin = decreased liver glucose production = increase liver nutrient uptake = increase peripheral uptake = decreased peripheral uptake
describe fasting state
decreased glucose production = increased liver gluconeogenesis = decreased peripheral uptake = increased lipolysis
describe plasma glucose level regulation
- high blood sugar = insulin release
- pancreas secretes glucagon and insulin
- low blood sugar = glucagon secretion > glycogen > glucose
roles of insulin in liver
inhibits gluconeogenesis
glycogen synthesis
lipogenesis
role of insulin in striated muscle
increased glucose uptake
increased glycogen synthesis
increased protein synthesis
role of insulin in adipose tissue
increase glucose uptake
increase lipogenesis
decreased lipolysis
insulin and counter regulatory hormones
- insulin = glucose storage
- glucagon = gluconeogenesis and glycogenolysis, fatty acid release
- epinephrine = glycogenolysis and fatty acid release
- cortisol = amino acid mobilisation and gluconeogenesis
- growth hormone = stimulates lipolysis and inhibits insulin action
what is diabetes mellitus
chronic hyperglycaemia, glycosuria and abnormalities of lipid and protein metabolism
type 1 = deficiency in insulin secretion
type 2= target organ resistant to insulin secretion
describe type 1 diabetes
mainly in children and young adults
sudden onset
commonest cause = autoimmune destruction of B cells
pathogenesis
- destruction of B cella begins with auto antigen formation
-autoantigens presented to T lymphocytes to initiate immune response
- circulating autoantibodies to various cell antigens against glutamic acid deoxycarboxilase
most common antibody = islet cell antibody
describe amylin
glucoregulatory peptide hormone co-secreted with insulin
lower blood glucose by slowing gastric emptying and surpressing glucagon output from pancreatic cells
metabolic complications of T1DM
diabetic coma
ketoacidosis
describe type 2 diabetes
due to lifestyle factors and lack of exercise
slow onset
patients middle aged = prevalence increases with age
strong familiar incidence
pathogenesis uncertain
describe metabolic complications of T2DM
low insulin = increased gluconeogenesis and glycogenolysis which leads to hyperglycaemia > glycosuria
glycosuria = osmotic diuresis = loss of h20 and electrolytes = dehydration/increased blood viscosity = thrombosis
diagnosis
- polyuria/polydispasia/weight loss for T1DM
how to do the oral glucose tolerance test
to check ability of metabolising glucose
- 75g oral glucose, test after 2 hours
- blood samples collected at 0 and 120 mins after glucose
describe diabetes treatment
T1DM = insulin therapy T2DM = diet and exercise, oral mono therapy, oral combination drugs, insulin and orally
drug treatment for T2DM
metformin
sulfonylureas = causes hypoglycaemia
thiazolidinediones = activates receptors, decrease insulin resistance
SGLT2 inhibitors = promotes glucose excretion
incretin target drugs = DP4-inhibitors and synthetic GLP-1 analogues
monitoring glycemic control
to prevent complications or avoid hypoglycaemia
self monitoring encouraged = capillary blood measurement and urine analysis
long term diabetes complications of diabetes
in both T1 and T2
- microvascular disease = retinopathy/nephropathy and neuropathy
- macrovascular disease = related to atherosclerosis heart attack/stroke
- exact mechanism of complications are unclear
what is hypoglycaemia
plasma glucose < 25mmol/L
caused by:
drugs
T1DM
hypoglycaemia in patients without diabetes
alcohol
endocrine disorders e.g cortisol disorder
inherited metabolic disorders
insulinoma
what does ethanol do
inhibits gluconeogenesis but not glycogenolysis
describe sepsis
cytokine accelerated glucose utilisation and induced inhibition of gluconeogenesis in setting of glycogen depletion
describe post-prandial hypoglycaemia
decrease in blood sugar usually recurrent within 4 hours of eating
cause = unclear
- benign tumour in pancreas = overproduction of insulin
- too much glucose used up tumour
- deficiencies in counter-regulatory hormones e..g glucagon
