C - Hypoglycaemia

Question 1

what key factor does treatment of hypoglycaemia depend on

Answer 1

whether pt is conscious or not

Question 2

Mx of hypoglycaemia for alert and orientated pt

Answer 2

oral carbs
rapid acting: juice / sweets
longer acting: sandwich

Question 3

Mx of hypoglycaemia for drowsy / confused with a good swallow pt

Answer 3

buccal glucose
rapid acting: eg hypostop / glucogel
longer acting: IV access ?

Question 4

Mx of hypoglycaemia for unconscious pt or poor swallow pt

Answer 4

IV access
20% glucose IV

Question 5

Mx of hypoglycaemia if deteriorating / refractory / insulin induced / difficult IV access

Answer 5

IM / SC img glucagon

Question 6

what must be simultaneously done when Tx hypo

Answer 6

continuous monitoring
- keep rechecking the glucose

Question 7

what can extravasation of glucose cause

Answer 7

irritation and phelbitis

Question 8

how long does glucagon take to work and why

Answer 8

15-20 mins
mobilised glycogen stores

Question 9

what is the danger of using glucagon

Answer 9

rebound hypoglycaemia

Question 10

who can’t be given glucagon and why

Answer 10

liver failure pts
- no glycogen stores to mobilise

Question 11

define hypoglycaemia in terms of glucose level

Answer 11

hard to say
- on wards: BM below 4 mmol/L
- sometimes below 3.5

Question 12

what is a worrying blood sugar in a neonate

Answer 12

2.5

Question 13

symptoms of hypoglycaemia

Answer 13

can be none
adrenergic: tremor, palpitations, sweating, hungry
neuroglycopaenic: somnolence, confusiom, incoordination, seizures, coma

Question 14

what is it called when you get no symptoms of hypoglycaemia

Answer 14

loss of hypoglycaemia awareness

Question 15

who gets loss of hypoglycaemia awareness

Answer 15

people who are having frequent hypos (insulin T1DM)

Question 16

what 3 factors define hypoglycaemia

Answer 16

low glucose
symptoms
relief of symptoms with glucose administration

Question 17

what is the first physiological response to low glucose

Answer 17

pancreas stops making insulin & starts making glucagon

Question 18

what is the effect of the body reducing insulin and producing glucagon in response to low glucose

Answer 18

reduced peripheral uptake of glucose
increased glycogenolysis
increased gluconeogenesis
increased lipolysis

Question 19

where is glycogen stored

Answer 19

liver

Question 20

what is glycogen

Answer 20

store of glucose

Question 21

what is gluconeogenesis

Answer 21

production of glucose from amino acids

Question 22

how are ketones produced in response to low glucose

Answer 22

low glucose
–> reduced insulin production and increased glucagon production in pancreas
–> increased lipolysis
–> increased free fatty acids
–> beta oxidation (ATP generation from burning FFAs in mitochondria)
–> increased ketone body production

Question 23

are ketones formed when even small amounts of insulin are circulating

Answer 23

NO - only formed when insulin suppressed

Question 24

what is a later response of the body to low glucose

Answer 24

low neuronal glucose sensed by hypothalamus
–> sympathetic activation producing catecholamines
also
–> ACTH, cortisol, GH production

Question 25

how do you diagnose hypoglycaemia in healthy people

Answer 25

conduct a prolonged fast to demonstrate it

Question 26

gold standard way of measuring glucose

Answer 26

venous glucose

Question 27

why is cap blood glucose not as useful

Answer 27

measured in whole capillary blood with poor precision tools that aren't quality controlled

Question 28

why is venous blood glucose gold standard

Answer 28

lab analysis with quality control tube contains fluoride oxalate

Question 29

causes of hypo without DM

Answer 29

fasting / reactive paeds vs adult critically unwell organ failure - renal / liver hyperinsulism post gastric bypass drugs extreme weight loss factitious

Question 30

why does liver / kidnet failure give you hypos

Answer 30

liver - no stores of glycogen kidney - no gluconeogenesis

Question 31

what is the leading cause of hypos in people with DM

Answer 31

mismatch between carbs eaten and meds taken

Question 32

other causes of hypos in DM

Answer 32

medications inadequate carb intake / missed meal impaired awareness of hypos xs alcohol strenuous exercise AI conditions eg Addisons

Question 33

what drugs other than insulin causes hypos

Answer 33

* sulphonylureas * meglitinides (not used as much) GLP 1 agonists with insulin

Question 34

what non DM drugs increase risk of hypos

Answer 34

beta blockers alcohol

Question 35

what biochemical tests need to be done to determine cause of hypoglycaemia

Answer 35

insulin levels c-peptide drug screen auto ABs cortisol / GH free fatty acids / blood ketones lactate

Question 36

when should biochemical tests be done to determine cause of hypo in non DM pts

Answer 36

only when they're having the hypo !! useless if they're not

Question 37

what is C peptide

Answer 37

a marker of how much insulin the pancreas is making

Question 38

what is the use of measuring C peptide and not just insulin

Answer 38

insulin reading tells you how much insulin is in the blood C peptide tells you how much of that insulin was made by the pancreas - ie excludes exogenous insulin from injections

Question 39

what are the 3 classifications of hypos based on insulin and C peptide

Answer 39

hypoinsulinaemic hypo (low insulin & CP) hyperinsulinaemic hypo (high insulin & CP) exogenous insulin (high insulin, low CP)

Question 40

what does hypoinsulinaemic hypo indicate

Answer 40

normal response to a hypo - ie hypo is not caused by faulty insulin production

Question 41

what does hyperinsulinaemic hypo indicate

Answer 41

hypo caused by too much insulin production

Question 42

what does exogenous insulin hypo indicate

Answer 42

likely factitious insulin injection to intentionally cause hypo in non DM pt (this is also seen in DM pts, but you wouldn't bother measuring insulin & CP as you assume it is due to exogenous insulin already)

Question 43

what causes of hypoglycaemia would have a hypoinsulinaemic hypo

Answer 43

all systemic causes - starving / fasting - exercise - critically ill - hypopituitarism / adrenal failure - liver failure - anorexia

Question 44

what type of hypo do neonates have

Answer 44

hypoinsulinaemic hypo (normal)

Question 45

why do neonates get hypoglycaemia

Answer 45

inadequate glycogen and fat stores

Question 46

risk factors for neonatal hypoglycaemia

Answer 46

premature co-morbidities IUGR SGA inborn metabolic defects

Question 47

give an example of an inborn metabolic defect that causes neonatal hypoglycaemia and the effect of this

Answer 47

fatty acid oxidation defect - no ketones produced but high fatty acids

Question 48

causes of hyperinsulinaemic hypoglycaemia

Answer 48

islet cell tumour - insulinoma drugs eg insulin, sulphonylureas islet cell hyperplasia rare genetic forms of hyperinsulism rare AI

Question 49

3 causes of islet cell hyperplasia

Answer 49

infant of diabetic mother beckwith weidemann syndrome nesidioblastosis

Question 50

what is the commonest cause of hyperinsulinaemic hypoglycaemia

Answer 50

drugs the others are super rare

Question 51

Ix for hyperinsulinaemic hypoglycaemia due to ?insulinoma

Answer 51

glucose (low) insulin (high) c peptide (high) sulphonylurea drug screen ( must be -'ve to diagnose insulinoma)

Question 52

describe how insulin is secreted in pancreas

Answer 52

glucose enters beta cell undergoes glycolysis via glucokinase ATP and glucose-6-P is produced ATP closes the K+ channel K+ prevented from leaving cell, so depolarises membrane Ca2+ influx Preformed insulin in vesicles fuse with membrane and are released

Question 53

how do sulphonylureas work

Answer 53

they bind to the K+ channel (Sur 1 subunit) in beta islet cells and force it closed, irrespective of glucose level. this causes membrane depolarisation and Ca influx which releases insulin from their vesicles

Question 54

prevalance of insulinoma

Answer 54

1-2 million per year

Question 55

when does hypoglycaemia occur in insulinoma

Answer 55

fasting only

Question 56

what % of insulinomas are malignant? associated with MEN1?

Answer 56

10% malignant 8% associated with MEN1

Question 57

Tx of insulinoma

Answer 57

resection

Question 58

what is the rare cause of low glucose/insulin/CP/FFA AND ketones?

Answer 58

non islet cell tumour hypoglycaemia eg secrete big IGF2 (an insulin like factor that mimicks insulin)

Question 59

examples of non islet cell tumours causing hypos

Answer 59

mesenchymal tumours - mesotheliomas / fibroblastomas epithelial carcinomas

Question 60

who gets reactive / post prandial hypos

Answer 60

post gastric bypass surgery hereditary fructose intolerance early / pre DM

Question 61

why do anorexics have hypos

Answer 61

poor glycogen stores in liver