diabetes and hypoglycaemia

Question 1

describe blood glucose/homeostasis

Answer 1

glucose major energy substrate

levels maintained by:

• dietary carbohydrates
• glycogenolysis
• gluconeogenesis

Question 2

describe fed state

Answer 2

increased plasma glucose = increased insulin = decreased liver glucose production = increase liver nutrient uptake = increase peripheral uptake = decreased peripheral uptake

Question 3

describe fasting state

Answer 3

decreased glucose production = increased liver gluconeogenesis = decreased peripheral uptake = increased lipolysis

Question 4

describe plasma glucose level regulation

Answer 4

1. high blood sugar = insulin release
2. pancreas secretes glucagon and insulin
3. low blood sugar = glucagon secretion > glycogen > glucose

Question 5

roles of insulin in liver

Answer 5

inhibits gluconeogenesis
glycogen synthesis
lipogenesis

Question 6

role of insulin in striated muscle

Answer 6

increased glucose uptake
increased glycogen synthesis
increased protein synthesis

Question 7

role of insulin in adipose tissue

Answer 7

increase glucose uptake
increase lipogenesis
decreased lipolysis

Question 8

insulin and counter regulatory hormones

Answer 8

1. insulin = glucose storage
2. glucagon = gluconeogenesis and glycogenolysis, fatty acid release
3. epinephrine = glycogenolysis and fatty acid release
4. cortisol = amino acid mobilisation and gluconeogenesis
5. growth hormone = stimulates lipolysis and inhibits insulin action

Question 9

what is diabetes mellitus

Answer 9

chronic hyperglycaemia, glycosuria and abnormalities of lipid and protein metabolism

type 1 = deficiency in insulin secretion
type 2= target organ resistant to insulin secretion

Question 10

describe type 1 diabetes

Answer 10

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

Question 11

describe amylin

Answer 11

glucoregulatory peptide hormone co-secreted with insulin

lower blood glucose by slowing gastric emptying and surpressing glucagon output from pancreatic cells

Question 12

metabolic complications of T1DM

Answer 12

diabetic coma

ketoacidosis

Question 13

describe type 2 diabetes

Answer 13

due to lifestyle factors and lack of exercise
slow onset
patients middle aged = prevalence increases with age
strong familiar incidence
pathogenesis uncertain

Question 14

describe metabolic complications of T2DM

Answer 14

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

Question 15

how to do the oral glucose tolerance test

Answer 15

to check ability of metabolising glucose

• 75g oral glucose, test after 2 hours
• blood samples collected at 0 and 120 mins after glucose

Question 16

describe diabetes treatment

Answer 16

T1DM = insulin therapy
T2DM = diet and exercise, oral mono therapy, oral combination drugs, insulin and orally

Question 17

drug treatment for T2DM

Answer 17

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

Question 18

monitoring glycemic control

Answer 18

to prevent complications or avoid hypoglycaemia

self monitoring encouraged = capillary blood measurement and urine analysis

Question 19

long term diabetes complications of diabetes

Answer 19

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

Question 20

what is hypoglycaemia

Answer 20

plasma glucose < 25mmol/L
caused by:
drugs
T1DM

Question 21

hypoglycaemia in patients without diabetes

Answer 21

alcohol
endocrine disorders e.g cortisol disorder
inherited metabolic disorders
insulinoma

Question 22

what does ethanol do

Answer 22

inhibits gluconeogenesis but not glycogenolysis

Question 23

describe sepsis

Answer 23

cytokine accelerated glucose utilisation and induced inhibition of gluconeogenesis in setting of glycogen depletion

Question 24

describe post-prandial hypoglycaemia

Answer 24

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

Question 25

signs and symptoms of hypoglycaemia

Answer 25

1. neurogenic = falling glucose levels and activated by ANS and mediated by sympathcadrenal release of catecholamines and Act
   mood changes/paleness/hunger/sweating/blurred vision
2. neuroglycopenia
   due to neuronal glucose deprivation
   confusion/difficulty speaking/ataxia