Hypoglycaemia Flashcards
Define the term “hypoglycaemia”
Defined as low plasma glucose concentration (< 4 mmol/L)
What is the plasma glucose concentration that defines hypogylcaemia
< 4 mmol/L
Hypoglycaemia is very common among diabetic patients treated with which medication
Insulin or sulphonylureas
When blood glucose concentration falls, there is activation of four counterregulatory mechanisms.
Name these
- Body decreases insulin secretion – immediate response
- Increase in glucagon secretion
- Increase in adrenaline secretion
- Secretion of cortisol and growth hormone – late response
What are the two main counterregulatory mechanism to hypoglycaemia
Decrease in insulin secretion
Increase in glucagon secretion
What level of hypoglycaemia stimulates the autonomic system causing the autonomic symptoms
< 3.1 mmol/L
What is the most common cause of hypoglycaemia
Most commonly occurs in association with treatment for diabetes mellitus e.g. insulin, Sulphonylureas
What is the most common cause of hypoglycaemia in non-diabetics
Insulinoma
What is an insulinoma
Benign pancreatic tumour of the beta cells causing excess insulin secretion
Naem some of the causes of hypoglycaemia
- Treatment for diabetes mellitus e.g. insulin, Sulphonylureas - most common in diabetics
- Insulinoma – benign pancreatic tumour of the beta cells causing excess insulin secretion - most common in non-diabetics
- Alcohol
- Sepsis
- Malnourishment
- Adrenal insufficiency
- Paraneoplastic syndrome – secretion of insulin-like growth factor
What is the blood glucose concentrations that cause autonomic symptoms (hypoglycaemia)
< 3.1 mmol/L
What is the blood glucose concentrations that cause neuroglycopenic symptoms (hypoglycaemia)
< 2.8 mmol/L
What causes autonomic symptoms associated with hypoglycaemia
The release of glucagon and adrenaline
What causes neuroglycopenic symptoms associated with hypoglycaemia
Inadequate glucose supply to the brain
Name some of the autonomic symptoms of hypoglycaemia
Tremor
Palpitations
Anxiety
Sweating
Hunger
Paraesthesia
Name some of the neuroglycopenic symptoms of hypoglycaemia
Dizziness
Weakness
Drowsiness
Confusion
Seizures
Coma
Why do patients with diabetes have reduced symptoms and presentation with severe hypoglycaemia
This is because patients with diabetes may lose their hypoglyaemic awareness
Occur in patients with type 1 and long-standing type 2 diabetes
The diagnosis of hypoglycaemia is based on
Capillary blood glucose or serum blood glucose measurements
What is the name given to the collection of three signs that is used as a formal diagnosis of hypoglycaemia
Whipple’s triad
Whipple’s triad refers to a collection of three signs that is used as a formal diagnosis of hypoglycaemia .
Name the 3 signs
Low blood glucose concentration
Symptoms of hypoglycaemia
Reversal of symptoms when blood glucose concentration is restored
In what patient group is the Whipple’s triad not clinically relevant for
Those with diabetes as they have reduced hypoglycaemic awareness
Name the key investigation for hypoglycaemia
Capillary blood glucose
OR
Serum blood glucose measurements
Name the other investigations that may be useful to aid in the investigation of hypoglycaemia
Serum insulin, C-peptide and proinsulin – to distinguish the presence of exogenous and endogenous insulin
Abdominal CT/MRI – to localise an insulioma
8am cortisol and/or synacthen (synACTHen) testing – for adrenal insufficiency
Serum insulin, C-peptide and proinsulin can be used to distinguish the presence of exogenous and endogenous insulin.
What would you expect the levels to be for an endogenous production of insulin
[High, Low, Normal]
High insulin
AND
High C-peptide and proinsulin
Serum insulin, C-peptide and proinsulin can be used to distinguish the presence of exogenous and endogenous insulin.
What would you expect the levels to be for an exogenous production of insulin
[High, Low, Normal]
High insulin
AND
Low C-peptide and proinsulin
How woud you manage mild/moderate hypoglycaemia
Oral glucose (10-20g) given in liquid, gel or tablet form
Quick acting carbohydrate e.g. GlucoGel, Dextrogel, sweets.
Followed by slow acting carbohydrates e.g. toast
How woud you manage severe hypoglycaemia
ABCDE appraoch
IV load of glucose e.g. 200ml IV 10% dextrose
If not access, subcut or intramuscular injection of 1mg glucagon
