hypoglycaemia Flashcards
acute mx of hypoglycaemia if pt alert and orientated
oral carbs
rapid acting - sweets/juice
longer acting - sandwich
deteriorating/refractory/insulin induced/difficult IV access - consider IM/SC glucagon
acute mx of hypoglycaemia if the patinet is drowsy/confused but swallow intact
buccal glucose
short acting - eg hypostop/glucogel
long acting - start thinking IV access
deteriorating/refractory/insulin induced/difficult IV access - consider IM/SC glucagon
acute mx of hyoglycaemia if unconscious or concerned about swallow
IV access
short acting - 20% glucose IV
long acting - 20% glucose
deteriorating/refractory/insulin induced/difficult IV access - consider IM/SC glucagon
caveats to consider when treating hypoglycaemia
need continuous monitoring
beware extravasation of IV glucose - irritant, phlebitis
glucagon mobilises glycogen stores - takes 15-20mins to work
need to check at 15-20 mins to see if the glucose has bumped up - and then check after this because reason for hypo might persist
what is the definition of hypoglycaemia
<4mmol/L - but sugar can regularly drop below this
abnormal when getting the sx of low blood sugar
however - can get impaired awareness
hypo when sx are relieved with glucose administration
sx of hypoglycaemia
first adrenergic
* tremor
* palpitations
* sweating
* hunger
then neuroglycopaenic
* somnolence
* confusion
* incoordination
* seizure
* coma
effect of low glucose on hormones
pancreas stop making insulin
increase glucagon
both lead to:
* reduce peripheral uptake of glcuose
* increased gluconeogenesis (from aa)
* increase glycogenolysis (liver)
* increase lipolysis (only if 0 insulin) -> increase in free atty acids -> beta oxidation -> increased ketone body
then low glucose sensed in hypothalamus -> SNS activation with catecholamines, then ACTH, cortisol, GH
first thing to when suspect hypoglycaemia
check actual hypo
easy to check when have dm - most will have glucometers
in healthy person - need to try to capture the hypo - bring into investigation unit - undertake prolonged fast for 72hr to precipitate hypo
glucose measurement
CBG - measured in whole blood, point of care, poor precision at low glucose level, not quality controlled
gold standard is venous glucose measyrement - collect in tube preserved with fluide oxalate, analysed in lab
causes of hypoglycaemia
fasting or reactive (ie bypass surgery)
paediatric vs adult
critically unwell
organ failure - liver = cant store glycogen // renal = where most gluconeogenesis occurs.
hyperinsulinism
drugs
extreme wht loss
factitious
diabetes
causes of hypos in diabetics q
meds - insulin and sulphonylureas (gliclazide)
inadequate carb intake/missed meal
impaired awareness
excessive alcohol
strenuous exercise and not reducing insulin
co-existing autoimmune eg Addison’s
meds that cause hypos
glucose lowering therapies
* sulphonylureas
* meglitinides
* glp-1 agents - only if given in conjunction with insulin because it boosts insulin production
insulin
* rapid acting with meals - inadequate meal
* long acting at night or in between meals
B blockers
salicyclates
alcohol - inhibits lipolysis
co-morbidities that can cause hypoglycaemia
renal/liver failure - alter drug clearance - dose reduction needed
addisons -> hypo
how can continuous glucose monitoring be helpful
see where the glucose level is flatlining - if stay at minimum readable value (2.2) for prolonged time - suggest impaired awareness
so have tech that stop them hypoing
how do we differentiate causes of hypoglycaemia outside of diabetes
hx and ex
ix - take bloods at time of hypo during 72hr fast
* insulin levels
* c peptide
* drug screen
* auto-Ab
* cortisol/GH
* FFA/blood ketones
* lactate
* special tests - IGFBP/IGF-2/Carnitines
summarise the structure of insulin
proinsulin is made of c-peptide and insulin
c-peptide levels are a good marker of beta cell function
insulin hlaf life 4-6 minutes
c-peptide half life 30mins
classification of hypos using c peptide
causes of hypoinsulinaemic hypoglycaemia
fasting/starvation
strenuous exercise
critical illness
endocrine def - hypopit, adrenal failure
liver failure
anorexia nervosa
causes of neonatal hypoglycaemia
explainable:
* premature, co-morbidities, IUGR, SGA
* inadequate glycogen and fat stores
* should improve with feeding
pathological
* inborn metabolic defects
what happens with neonatal hypoglycaemia with suppressed insulin and c peptide
FFA raised but low ketones
can be due to inherited metabolic disorders:
* fatty acid oxidation defect: no ketones, high FFA, low insulin
* GSD type 1 (gluconeogentic disorder)
* medium chain acyl CoA dehydrogenase def
* carnitine disorders
what is inappropriate hypoglycaemia and causes
when glucose is low due to high insulin
islet cell tumours - insulinoma
drugs - insulin, sulphonylurea
islet cell hyperplasia - infant of diabetic mother, beckback weidemann syndrome, nesidioblastosis
rare genetic forms
autoimmune
what is inappropriate hypoglycaemia and causes
when glucose is low due to high insulin
islet cell tumours - insulinoma
drugs - insulin, sulphonylurea
islet cell hyperplasia - infant of diabetic mother, beckback weidemann syndrome, nesidioblastosis
rare genetic forms
autoimmune
what is dx - low glucose, high insulin and c peptide
means insulin is endogenous - so ddx: insulinoma vs sulphonylurea abuse
drug screen - urine/serum
-ve sulphonylurea screen is needed to dx insulinoma
summarise normal insulin secretion and how do sulphonylureas work
Glucose into B cecll - > glycolysis -> atp
K channel close
Membrane depol
Ca comes in
Insulin granules fuse with membrane and release insulin
Sulphonylurea bind to K+ATP channel -> closes independently of glucose - get release of insulin
