12.7 Hypoglycemia Flashcards
Take home messages
- Hypoglycemia - excessive lowering of blood glucose
- unexplained reduced conciseness = check for hypoglycaemia
- DM - insulin deficiency (-> Hyperglycemia)
- treatment: reduces blood glucose
What is the normal blood glucose range?
3.9-5.5 mmol/L
Define hypoglycemia
- abnormal reduction or lowering of blood glucose
- common in patients with diabetes mellitus on treatment that aims to reduce elevated blood glucose levels
- spontaneous hypoglycemia in otherwise normal and healthy individuals rare, but important to recognise
Neuroglycopenia
Brain not supplied with enough glucose
adrenergic response
- noradrenaline / acetylcholine
- mobilize glycogen and fat as additional fuel
- Liver: Glucose ➡️Brain
- Fat stores: FFA ➡️other
hormonal response
- Insulin ⬇️
-Insulin antagonists ⬆️
➡️Cathecholamines (adrenaline): alarm
➡️Glucagon: immediate, most important, silent
➡️Cortisol (slower response)
➡️GH (slower response)
What is the most important protector against hypoglycemia?
Glucagon (acts immediately)
- released when glucose and insulin in low
Role of catecholamines (adrenaline)
- mainly responsible for hypoglycemic symptoms
- ALARM
- acts immediately, major back-up system for glucagon
What does cortisol and growth hormone do with glucose balance
- Cortisol: mobilize energy stores (2-3 hrs)
- Growth hormone: antagonize insulin-effects (after hours)
- these hormones work synergistically - combined hyperglycemic effect more than individual impact
- Hypoglycemia: ⬆️ cortisol; ⬆️ GH
Symptoms of hypoglycemia are due to:
- counter regulatory mechanisms NB: adrenergic response
- Adrenergic symptoms: BG < 3.8mmol/l
- inadequate glucose delivery to the brain with resultant dysfunction due to neuroglycopenia
- Neuroglycopenic symptoms: BG < 2.8mmol/l
Adrenergic symptoms
- Anxiety
- Tremor
- Sweating
- Hunger
- Palpitations
- more prominent
- evokes similar symptoms repeatedly in same patient
- ALARM: main warning of falling blood glucose level
Neuroglycopenia
- Vision
- Weakness
- Tiredness
- Confusion
- Behavioral abnormalities
- Dizzy…..
- Convulsions
- Coma
- patient presents with subtle to overt features of brain dysfunction
Diagnosis of Hypoglycemia
- suspect clinically: symptoms and signs non-specific and raise suspicion only
- confirm biochemically: ideally laboratory confirmation of low blood glucose
- Whipple triade must be present especially in patients without known diabetes
- remember normal physiology and expected low insulin if hypoglycemia
Nb Whipples traide (diagnostic triade for hypoglycemia)
Traide
- symptoms and signs of hypoglycemia
- laboratory confirmed plasma glucose <2.5 (2.7) mmol/l [<45 (50)mg/dl]
- reversal of symptoms with glucose administration
- blood glucose values applicable to non-diabetic population
- must confirm clinical suspicion biochemically
- symptoms non-specific
- in patients with diabetes on glucose lowering treatment, we use a higher cut-off for diagnosing hypoglycemia, namely 4.0mmol/L (72mg/dl) as these patients are at high risk for low sugars
Classification of hypoglycemia
(1) in background population without diabetes mellitus
- a blood glucose below 2.7 (2.5 mol/L) along with other Whipple triad criteria
(2) in patients with diabetes mellitus on treatment
- classification based on clinical presentation and blood glucose measurement
- includes all episodes of an abnormally low plasma glucose concentration (with or without symptoms) that expose the individual to harm:
• Level 1: blood glucose less than 3.9 mmol/L (54mg/dl) but _>3mmol/L (70mg/dI)
• Level 2: blood glucose < 3mmol/L
• Level 3: any episode of hypoglycemia where third-party assistance or other resuscitative measures required ( do not wait for sugar test result, treat immediately)
Etiology / pathophysiology
fasting hypoglycemia
- in an otherwise healthy person should always be thoroughly investigated. May indicate the presence of a serious, and potentially curable, underlying condition.
postprandial hypoglycemia
- is self-limiting, do not produce ominous symptoms, is non-progressive and rarely suggestive of underlying disease. Is mostly seen in association with previous gastric surgery / psycho- pathology
Fasting hypoglycemia presents
- at night-time
- early morning on waking
- provoked by exercise
- during fasting period in the day-time