Chem path 17 - hypoglycaemia Flashcards
What is the management of acute hypoglycaemia dependent on?
How alert the patient is
How woudl you manage an alert and oriented pt?
Oral carbohydrates followed by rapid acting glucose e.g. juice/sweets and then long acting carbs e.g. sandwich
How would you manage a drowsy pt who’s swallow is still intact?
Buccal glucose e.g. glucogel (buccal/ sublingual given as it avoids hepatic first pass metabolism)
How would you manage an unconscious pt or if you are concerned about their swallow?
IV access, 50ml 50% glucose OR 100ml 20% glucose
if the pt starts deteriorating despite treatment what would you consider?
1mg IM glucagon
If someone is NOT responding and IV access is difficult, what would you offer?
IM/SC glucagon
What are the caveats to using glucagon?
Takes 15-20 mins to act as mobilises glycogen stores
Requires continuous monitoring
What if there are no glycogen stores in 1st place? e.g. anorexic/hepatic failure
Rebound hypoglycaemia as will cause insulin release
Definition of hypoglycaemia normally, in diabetics and in paediatrics
<4.0mmol/L
<3.5 mmol/L diabetic
<2.5mmol/L paediatrics
Outline wipple’s triad which defines hypoglycaemia
low glucose
symptoms
relief of symptoms with glucose administration
2 forms of symptoms with hypoglycaemia?
Neuroglycopaenic - sommolence, confusion, incoordination, seizures, coma
Adrenergic - tremors, palpitations, sweating, hunger
What happens when a patient has recurrent episodes of hypoglycaemia?
They develop hypoglycaemia unawareness
What is the order of the physiological changes which take place following the detection of hypoglycaemia?
- Suppression of insulin
- Release of glucagon
- Release of adrenaline
- Release of cortisol, GH, ACTH etc
What effects does glucagon have?
- reduce peripheral uptake of glucose
- gluconeogenesis
- glycogenolysis
- Increase lipolysis
What happens to FFAs?
As there is an increase in glucose, there is also an increase in FFAs. FFAs enter the beta-oxidation cycle and generate ATP. However, if you have lots of FFAs in the body not all of them can undergo beta oxidation so some become ketone bodies.
Where can gluconeogenesis occur other than the liver?
In the kidneys. This is why patients with renal failure can sometimes suffer hypos.
How do you investigate hypoglycaemia in a healthy person?
Conduct a prolonged fast (72 hours), a healthy person should never become hypoglycaemic.
How do you measure blood glucose?
Venous blood sample - fluoride oxalate (grey top tube),2ml blood, analysed in lab is GOLD standard
Capillary glucose - point of care test with instant results, poor precision at low glucose levels
Continuous glucose monitoring
Causes of hypoglycaemia in non-diabetics
Fasting Organ failure Insulinoma Factitious Drugs/alcohol Extreme weight loss Critically unwell Post-gastric bypass
Causes of hypoglycaemia in diabetics
- Medications (inappropriate insulin administration)
- Inadequate carbohydrate intake/missed meal
- Impaired awareness
- Excessive alcohol
- Strenuous exercise
- Co-existing autoimmune conditions
Diabetic drugs associated with hypoglycaemia
Oral hypoglycaemic agents e.g. sulphonylureas e.g. gliclazide, GLP-1 agents
Insulin
Beta-blockers, salicylates, alcohol
Which 2 co-morbidities are commonly associated with hypos in diabetes patients? WHy?
Renal/liver failure - due to impaired clearance of DM drugs –> toxicity
What are some useful tests for differentiating the cause of hypoglycaemia?
Insulin, c-peptide, FFAs, ketones, drug screen
Compare the half lives and clearance of insulin and c-peptide
Insulin half-life is 4-6 mins and hepatic clearance
C-peptide half-life 30 mins, renally cleared
Hypo due to excess injected insulin would cause a high or low c-peptide?
LOW
