14. Hypoglycaemia Flashcards
How do you acutely manage a patient with hypoglycaemia who is alert and orientated?
Oral carbohydrates; rapid acting: juice/sweets; longer acting: sandwich. If deteriorating, refractory, insulin induced. difficult IV access, consider IM/SC 1 mg glucagon.
How do you acutely manage a patient with hypoglycaemia who is drowsy / confused but swallow intact?
Buccal glucose e.g. hypostop/glucogel; start thinking about IV access. If deteriorating, refractory, insulin induced, difficult IV access, consider IM/SC 1 mg glucagon.
How do you acutely manage a patient with hypoglycaemia who is unconscious or concerned about swallow?
IV access; 50 ml 50% glucose mini-jet; or 100 mls 20% glucose. If deteriorating, refractory, insulin induced, difficult IV access, consider IM/SC 1 mg glucagon.
What are three things must you be aware of when treating a patient with hypoglycaemia?
- Must treat and monitor. 2. Beware of extravasation of IV glucose: irritant, phlebitis. 3. Glucagon mobilises glycogen stores so takes 15-20 mins to work - are there glycogen stores to mobilise? Danger of rebound hypoglycaemia, as will cause insulin release
If patients are drowsy and confused but their swallow is intact, what should you give and how?
Glucose in gel form, usually given sublingually because that allows bypassing of hepatic first pass metabolism.
If patient is deteriorating/not responding, you give 1mg glucagon. What are the issues with this?
Can take 15-20 mins to cause a change in blood glucose. It is also important to consider whether the patient has glucagon stores that can be accessed. People with hepatic failure, or people who are starving/anorexic will not have much of a hepatic glycogen store that can be accessed with glucagon.
What can extravasation of IV glucose cause?
It is an irritant and can cause phlebitis
How can hypoglycaemia be defined?
Through blood glucose cut-offs and symptoms (adrenergic and neuroglycopenic). There has been a move away from setting an absolute blood glucose cut-off for hypoglycaemia, and this triad type structure has been adopted instead. Triad includes: low blood glucose, symptoms, and relief of symptoms with glucose administration.
What adrenergic symptoms suggest hypoglycaemia?
Tremors, palpitations, sweating, hunger
What neuroglycopenic symptoms suggest hypoglycaemia?
Somnolence, confusion, incoordination, seizures, coma
What is the blood glucose cut-off for hyypoglycaemia?
This varies but E.g. if the glucose drops below 4 mmol/L on a ward, we’d consider this to be low. However, the definition of clinically significant hypoglycaemia in neonates is when it drops < 2.5 mmol/L
What is the order in which physiological changes take place following the detection of hypoglycaemia?
Suppression of insulin, release of glucagon, release of adrenaline, release of cortisol
What happens in the counter-regulation of blood glucose, particularly when there is low glucose?
- The low glucose means that insulin is lowered and glucagon is increased.
- This leads to: reduced peripheral uptake of glucose; increased glycogenolysis; increased glucogenesis; increased lipolysis.
- This results in increased glucose and increased FFA.
- Increased FFA leads to beta-oxidation which generates ATP.
- If there are a lot of FFAs, not all can undergo beta-oxidation so some form ketone bodies.
- Low neuronal glucose is sensed in hypothalamus which leads to sympathetic activation (catecholamines) and ACTH, cortisol and GH production.
What are investigations for hypoglycaemia?
This is easy in a patient with diabetes - monitor their blood glucose. It is more difficult in an otherwise healthy person. You may need to conduct a prolonged fast to demonstrate hypoglycaemia. Normal people should never become hypoglycaemic. Measuring Glucose:
- Lab Glucose: Grey top (fluoride oxalate); Venous sample; 2 mls of blood; GOLD STANDARD to make the diagnosis; Result takes some time.
- Blood Glucose Meter; Point-of-care device;
Instant result; Capillary blood. BUT: Poor precision at low glucose levels and often poorly maintained.
What are the causes of hypoglycaemia in people WITHOUT diabetes?
Fasting or reactive; paediatric or adult; critically unwell; organ failure; hyperinsulinism; post-gastric bypass; drugs; extreme weight loss; factitious (artificially created i.e. an artefact)
What are the 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 co-morbidities).
What are diabetic medications?
- Oral Hypoglycaemics such as sulphonylureas; meglitinides; GLP-1 agents.
- Insulin: rapid acting with meals and long-acting.
- Other drugs such as: Beta-blockers; salicylates; alcohol (inhibits lipolysis)
How can diabetes with co-morbidities lead to hypoglycaemia?
· This can also lead to hypoglycaemia. Co-existing renal/liver failure alters drug clearance, and reduces the doses needed.
· Rarely, concurrent Addison’s disease can result in hypoglycaemia (polyglandular autoimmune syndrome)
· Poor awareness can occur due to autonomic neuropathy
How does continuous glucose monitoring work?
This device is applied to the abdominal wall with a small cannula that sits in the interstitial space in the subcutaneous fat. The sensor does NOT accurately read blood sugar when it drops below 2.2 mmol/L.
How can we differentiate between the causes of hypoglycaemia?
Thorough history and examination and biochemical tests.
