Diabetes Flashcards
what are the three main microvascular complications of diabetes?
neuropathy
nephropathy
retinopathy
how does microvascular compromise generally occur in diabetes?
reduced blood flow to small vessels, causing hypoperfusion of nerves in that area
which part of the body is most susceptible to diabetic neuropathy?
feet
what will peripheral neuropathy predominantly cause?
pain/loss of sensation in the feet/hands
true or false: neuropathy is more common in type 2 diabetes than type 1 diabetes
false
what are the major complications of peripheral neuropathy?
infections
ulcers
deformities
amputations
what is gustatory sweating?
abnormal function of sweat glands, causing profuse sweating at night or during meals
true or false: diabetes is the most common cause of kidney failure
true
what is a reliable sign of diabetic kidney failure that should be screened for?
raised albumin
list causes of false positives for microalbuminuria
menstruation pregnancy UTI vaginal discharge non diabetic renal disease
which class of drugs is useful for diabetics with kidney failure?
ACE inhibitors
what eye pathologies do people with diabetes get?
retinopathy
cataracts
glaucoma
visual blurring
what is the main sign of background retinopathy?
leaky blood vessels (dots)
what are the main signs of proliferative retinopathy?
angiogenesis due to ischaemia
haemorrhage
leaky blood
what are the main signs of diabetic maculopathy?
build up of fluid in macula, causing exudates
blurred vision or complete loss of vision
true or false: erectile failure occurs in about 50% of diabetic men
true
true or false: in scotland, incidence of diabetes has overtaken CVD and cancer
true
define diabetes mellitus
a group of metabolic diseases characterised by hyperglycemia, due to inadequate insulin production, availability or action
why is type 1 diabetes an example of absolute insulin deficiency?
insulin is not produced because the beta cells in the pancreas are destroyed
what is the normal range of glycated hemoglobin (HbA1c)?
41 m/m and below
what is the normal range for fasting glucose?
6mmol/l and below
what value of HbA1c is diabetes diagnosed at?
48mmol/mol and above
what value of fasting glucose is diabetes diagnosed at?
7mmol/l and above
what value of random blood glucose is diabetes diagnosed at?
11.1mmol/l
which antibodies are associated with type 1 diabetes?
anti-GAD
anti islet cell
true or false: autoantibodies in type 1 diabetes actually appear years before the onset of diabetes
true
list clinical features of type 1 diabetes
polyuria polydipsia weight loss fatigue ketonuria
what is the typical age of onset for type 1 diabetes?
pre school/pre puberty
another peak in late 30’s
which type of diabetes is more associated with obesity?
type 2
list clinical features of type 2 diabetes
thirst polyuria weakness thrush blurred vision neuropathy
what is LADA?
late onset autoimmune diabetes of adulthood
which type of diabetes is more associated with ketosis?
type 1
what does HbA1c provide a measure of?
glycated Hb
provides a measure of blood glucose over 2-3 months
list macro-vascular complications of diabetes
MI
stroke
list micro-vascular complications of diabetes
retinopathy
nephropathy
neuropathy
HLA genes represent how much of familial risk of type 1 diabetes?
30-50%
what is the highest risk genotype for type 1 diabetes?
DR3-DQ2
DR4-DQ8
true or false: people with pear shaped weight distribution have higher risk of CVD than those with apple shaped weight distribution
false
what are the main aims behind diabetes therapy?
alleviate hyperglycemic symptoms
weight loss
reduce risk of complications
what is the first line pharmacological therapy for type 2 diabetes?
biguanides (metformin)
give examples of sulphonylureas
gliclazide
glibenclamide
glimepiride
give an example of a thiazolidinedione (TZD)
pioglitazone
what are the main effects of metformin?
reduces insulin resistance
prevents vascular complications
reduces triglycerides and LDL
list some possible adverse effects of metformin
GI upset
lactic acidosis
liver failure
rash
true or false: sulphonylureas have more rapid reduction of hyperglycemia compared to metformin
true
true or false: sulphonylureas prevent micro and macro vascular complications
false
they do not prevent macrovascular complications
true or false: TZDs can cause weight gain
true
true or false: TZDs increase the risk of hip fractures
true
not recommended in those over 65
what are incretins?
hormones that cause intestinal secretion of insulin
name the two main incretin hormones
GLP-1 from L cells
GIP from K cells
list the effects of incretins
delay gastric emptying
decrease appetite
stimulate insulin secretion
reduce glucose production by liver
name a GLP-1 agonist that can be used for diabetes
exenatide
name a DPP-1 inhibitor that can be used for diabetes
sitagliptin
how are SGLT2 inhibitors useful in diabetes?
reduce reabsorption of glucose, causing glycosuria
what is a downside of SGLT2 inhibitors?
increase risk of UTIs
list ways to evaluate metabolic control of diabetes
HbA1c
blood glucose
ketone monitoring
urinalysis
what is the main treatment for type 1 diabetes?
insulin
list the devices available for administering insulin
syringe
disposable pen
cartridge pen
continuous subcutaneous pump
what is basal insulin?
background production of insulin to keep blood glucose normal outwith meal times
what is prandial insulin?
insulin produced in relation to increased glucose following a meal
when is the onset and peak action of rapid acting insulin analogues?
onset = 15 mins peak = 1-2 hours
give examples of rapid acting insulin analogues
novorapid
humalog
when is the onset and peak action of short acting insulin analogues?
onset = 30-60 mins peak = 2-4 hours
give examples of short acting insulin analogues
actrapid
humulin S
what is the onset of action of basal insulin analogues?
1-3 hours
give examples of basal insulin analogues
insulatard
humulin I
what is humalog Mix25 composed of?
25% short acting
75% intermediate acting
what is the aim behind a basal-bolus insulin regime?
mimic endogenous production
take short acting before a meal, long acting before sleeping
what is involved in a once daily insulin regime?
long/intermediate acting given before bed
not suitable for type 1
what is involved in a twice daily insulin regime?
injection before breakfast and dinner
high risk of hypoglycemia, only works if the patient eats three meals a day
what is the target for blood glucose pre-meal?
3.9-7.2 mmol/L
what is the target for blood glucose 1-2 hours after starting a meal?
less than 10 mmol/L
do insulin pumps deliver short, intermediate or long acting insulin?
short acting
what are the three main limitations of insulin injections vs pancreatic insulin?
injected into subcutaneous tissue instead of blood
slower peak
slow clearance
name a long acting human insulin injection
ultratard
name a long acting insulin analogue
lantus
levemir
list drug classes that increase secretion of insulin through insulin independent action
sulphonylureas
incretin analogues
DPP 4 inhibitors
list drug classes that decrease insulin resistance and reduced hepatic glucose output through insulin dependent action
biguanides
thiazolidinediones (TZD’s)
list a drug class that slows glucose absorption from the GI tract through insulin independent action
alpha glucosidase inhibitors
list a drug class that blocks reabsorption of glucose in the kidneys through insulin independent action
SGLT2 inhibitors
through which transporter does glucose enter the beta cell in the pancreas?
GLUT 2
what effect does ATP in the beta cell of the pancreas have on K channels?
closes them, causing depolarisation of the membrane
how is insulin released following depolarisation of the membrane of the beta cell?
depolarisation causes opening of the calcium channels, causing insulin containing vesicles to exocytose
list the components of the Katp channel
4 Kir6.2 units
4 SUR1 units
which part of the Katp channel does ATP bind to?
Kir6.2 unit
what binds to the SUR1 part of the Katp channel and what does this cause?
ADP-Mg
repolarisation to inhibit insulin secretion
how do sulphonylurea drugs work?
displace ADP-Mg from SUR1 on Katp channel to cause depolarisation to promote insulin release
true or false: the effect of sulfonylurea drugs is independent of glucose concentration
true
give examples of sulphonylureas
tolbutamide
glibenclamide
glipizide
what is the main difference between tolbutamide and glibenclamide?
glibenclamide is more potent and longer acting, so you only need to take it once a day
can sulfonylureas cause hypoglycemia?
yes
greater risk with long acting agents
how do glinides differ from sulphonylureas?
bind to specific part of SUR1
rapid action - less likely to cause hypoglycemia
what are the two main endogenous incretin hormones?
GLP-1
GIP
what effect does GLP-1 have on glucagon?
decreases glucagon release from alpha cells
give an example of an incretin analogue
exenatide
which enzyme rapidly inhibits the action of incretin hormones?
DPP-4
how do DPP-4 antagonists work?
inhibit DPP-4 to prolong actions of GLP-1 and GIP
give an example of a DPP-4 inhibitor
sitagliptin
what is the function of alpha-glucosidase in the intestine?
breaks down carbohydrates into absorbable glucose
how do alpha glucosidase inhibitors work?
inhibit alpha glucosidase to delay absorption of glucose, thus reducing postprandial increase in blood glucose
give an example of an alpha glucosidase inhibitor
acarbose
true or false: acarbose has a great risk of hypoglycemia
false
no risk at all
what is the first line therapy for type two diabetes?
biguanides
what is the proposed action of metformin?
reduces hepatic gluconeogenesis by stimulating AMPK
enhances glucose uptake by muscle
does metformin cause hypoglycemia?
no
true or false: metformin causes weight gain
false
causes weight loss
list a significant adverse effect of metformin
lactic acidosis
how do TZDs work?
agonist of PPAR alpha which is associated with RXR to enhance the transcription of genes that encode insulin signalling
which transported moves glucose into skeletal muscle?
GLUT4
true or false: TZDs can cause weight gain
true
how do SGLT2 inhibitors work?
block reabsorption of glucose in convoluted tube of nephron to cause glycosuria
name a SGLT2 inhibitor
dapagliflozin
what is the main adverse effect of SGLT2 inhibitors?
increased risk of UTI
thrush
give an example of TZD
pioglitazone
list the main diabetic emergencies
diabetic ketoacidosis HHS lactic acidosis alcoholic ketoacidosis hyperglycemia
what is diabetic ketoacidosis?
metabolic state that occurs in the context of insulin deficiency, resulting in increase of counter regulatory hormones
how do excess ketones form as a result of insulin deficiency?
increased lipolysis causes increased free fatty acid in the liver, producing more ketones
how does hyperglycemia result from insulin deficiency?
less glucose utilisation by muscle tissues
increased proteolysis
increased glycogenolysis
is DKA more common in type 1 or type 2 diabetes?
type 1
outline the biomechanical diagnosis of DKA
ketonemia greater than 3
glucose greater than 11
bicarbonate less than 15/pH less than 7.3
what is the most common precipitant of DKA?
non compliance with insulin therapy
list symptoms of DKA
thirst polyuria vomiting abdominal pain breathlessness acetone breath
what is the blood measurement of ketones?
beta-hydroxybutarate
what is the urine measurement of ketones?
acetoacetate
list some electrolytes that can be lost in DKA
sodium
potassium
phosphate
list the main complications of DKA
hypokalaemia
ARDS
cerebral oedema
aspiration
outline main initial treatment of DKA
fluids
potassium
insulin
why might ketonuria persist even after clinical improvement of DKA?
mobilisation of ketone stores from fat
list the typical features of hyperglycemia hyperosmolar syndrome (HHS)
high glucose
renal impairment
raised osmolality
less ketonaemic
how do you calculate osmolality?
(2 x [Na + K]) + urea + glucose
what is the normal range for osmolality?
285-295
true or false: DKA and HHS tend to occur in younger diabetics
false
DKA in younger, HHS in older
is HSS more commonly associated with type 1 or 2 diabetes?
type 2
how does treatment in HHS differ from DKA?
more slow and cautious, often just diet related
may not require insulin
vascular events are more likely
what is the normal range of lactate?
0.6-1.2
what is the normal anion gap?
10-18