Level 2 of 6Must-remember

Hypoglycaemia: recognition and emergency correction

Assess, manage and stay safe — enough on its own

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The card — assess, manage, caution

Assessment— look, ask, measure

Capillary glucose: measure it immediately in every patient with altered conscious level, seizure, focal neurological deficit, acute confusion, apparent intoxication, unexplained collapse or hypothermia, and in any person with diabetes who is acutely unwell.
Even when the cause looks obvious: check the glucose in the apparent hemiplegic stroke and the apparent drunk, because hypoglycaemia reproduces stroke, drunkenness, dementia, epilepsy and psychiatric illness exactly.
The treatment threshold: any value below 4.0 mmol/L (72 mg/dL) is hypoglycaemia and must be treated — "4 is the floor" — while a normal bedside value is sufficient to exclude it.
History to ask for: which glucose-lowering drug, what dose, at what time, missed meals or snacks, alcohol, exercise, vomiting, weight loss, recent acute illness, steroid withdrawal, and whether anyone else has access to insulin or tablets.
Ask how long the drug will keep working: sulphonylureas (glibenclamide, gliclazide, glipizide, glimepiride) and long- or intermediate-acting insulins (glargine, detemir, degludec, isophane, premixed) outlast any bolus, whereas metformin, DPP-4 inhibitors, thiazolidinediones, alpha-glucosidase inhibitors, GLP-1 receptor agonists and SGLT2 inhibitors do not cause hypoglycaemia when used alone.
In a person without diabetes: alcohol is the commonest cause, and a blood concentration as low as 45 mg/dL (9.8 mmol/L) can precipitate profound hypoglycaemia where glycogen is depleted, classically with coma and hypothermia.
On inspection: the patient may be sweating, pale, tremulous and tachycardic, or equally may be quiet, confused and hypothermic — no sign is specific and the diagnosis is made by measuring the glucose.
Autonomic (warning) symptoms: sweating, trembling, pounding heart, hunger, anxiety, paraesthesiae, feeling hot and pallor — these normally come first and prompt self-treatment.
Neuroglycopenic symptoms: difficulty concentrating, slurred speech, incoordination, drowsiness, delirium, irritability, altered behaviour, dizziness, visual disturbance, focal deficit including a dense hemiplegia with an extensor plantar, seizure, coma and rarely death.
Non-specific symptoms: nausea, tiredness and headache, which are easily attributed to something else.
Airway and conscious level: assess these before anything else, because they and not the glucose number decide the route of treatment.
Vital signs and bedside tests: pulse, blood pressure, oxygen saturation, core temperature (hypothermia is a genuine feature) and a 12-lead ECG, since the catecholamine surge causes QT prolongation and arrhythmia.
Grade the severity: Level 1 (alert value) below 3.9 mmol/L (70 mg/dL) but at or above 3.0 mmol/L; Level 2 (clinically significant) below 3.0 mmol/L (54 mg/dL); Level 3 (severe) any low glucose causing cognitive impairment such that another person's help is required.
Level 3 is a clinical, not a biochemical, category: a patient rescued by a paramedic at 3.5 mmol/L has had a Level 3 event and one who self-treats at 2.1 mmol/L has not, and Level 3 carries a mortality of up to 4% in insulin-treated patients.
Danger features that mark a high-risk episode: coma, seizure or focal deficit; failure to regain full consciousness within about 10 minutes of a documented glucose above 4.0 mmol/L; a sulphonylurea or long-acting insulin or deliberate overdose; recurrence despite treatment; hypothermia, malnutrition or chronic alcohol use; critical illness, chest pain, arrhythmia or ischaemic ECG changes; impaired awareness or a second episode within a week; no cause identifiable; any hypoglycaemic neonate or child in whom the cause is not obvious.
Age changes the picture and the mimics: older people show few autonomic symptoms and more visual disturbance, ataxia, falls and confusion (misdiagnosed as transient ischaemic attack, stroke or dementia), children show naughtiness, irritability, tantrums or unusual quietness, and infants show poor feeding, jitteriness, floppiness, apnoea, a high-pitched cry, hypothermia or seizure — while the adult mimics to consider are stroke, post-ictal state, alcohol, opioid or sedative intoxication, sepsis, DKA or hyperosmolar hyperglycaemic state, adrenal crisis, hepatic encephalopathy, arrhythmia, panic attack and phaeochromocytoma.

Management— do this, in order

Critical sample, only if it takes seconds: draw venous blood before giving glucose for laboratory glucose in a fluoride-oxalate tube, insulin, C-peptide, beta-hydroxybutyrate, cortisol, ethanol and a sulphonylurea screen; if blood cannot be obtained quickly, treat first, then sample and record that it was post-treatment.
Treat on the bedside value: never wait for the laboratory, and begin treatment as soon as the samples have been taken.
Airway and position first in the unconscious patient: recovery position, suction, chin lift, and oxygen to keep saturations at or above 94%.
Choose the route by the airway, not the number: a drowsy patient at 3.6 mmol/L needs parenteral treatment, whereas an alert patient at 2.4 mmol/L does not.
Alert, cooperative and swallowing safely — oral carbohydrate: 15–20 g of fast-acting glucose, that is 5–7 glucose (Dextrosol) tablets, 4–5 Glucotabs, a glucose drink, 150–200 mL of non-diet fizzy drink or fruit juice, or 3–4 teaspoons of sugar in water; do not exceed this.
Recheck and repeat orally: recheck the capillary glucose at 10–15 minutes and repeat the same 15–20 g if still below 4.0 mmol/L, but if three cycles (30–45 minutes) fail, abandon the oral route and give parenteral treatment.
Conscious but confused or aggressive with a safe airway — buccal gel: two tubes of 40% glucose gel squeezed between the teeth and the gums and never poured into the throat, rechecked at 10–15 minutes, moving to intramuscular glucagon or intravenous glucose if three cycles fail or the swallow becomes unsafe.
Unconscious, fitting, very aggressive or nil by mouth — intravenous glucose: 20% glucose 75 mL IV (= 15 g) over 15 minutes as first line, or 10% glucose 150 mL IV (= 15 g) over 15 minutes, which is equally acceptable and preferable in small veins.Doctor / Nurse
Where only 50% glucose is stocked: 50 mL (= 25 g) as a slow bolus into a large, freely running vein, followed by a 0.9% sodium chloride flush — and never in a child.Doctor / Nurse
After the intravenous dose: recheck the capillary glucose 10 minutes after the infusion finishes and repeat the same dose if it remains below 4.0 mmol/L, since there is no ceiling on repeating an appropriate dose.
No intravenous access — glucagon 1 mg intramuscularly into the deltoid or anterolateral thigh (subcutaneous is also effective and a relative can give it at home), followed by intravenous glucose once access is obtained.Doctor / Nurse
If two adequate parenteral doses fail: confirm the cannula has not tissued, repeat the bolus, then start a continuous 10% glucose infusion titrated against hourly capillary glucose to keep the value above 4.0 mmol/L.Doctor / NurseNot available at your setup — Infusion pump. If no infusion pump is available, titrate the drip rate manually against hourly capillary glucose.
Child, conscious and swallowing safely: oral fast-acting glucose approximately 0.3 g/kg — glucose tablets or 100–150 mL of non-diet sugary drink in an older child, a milk feed in an infant if feeding is safe — or 1–2 tubes of 40% glucose gel between teeth and gums if uncooperative with a safe airway.
Child, unconscious, fitting or unsafe swallow: 10% glucose 2 mL/kg (= 0.2 g/kg) by slow intravenous injection (alternative 20% glucose 2 mL/kg as a slow injection over 10 minutes), then 10% glucose 0.10 g/kg per hour (= 1 mL/kg/hour) titrated upwards against hourly glucose.Doctor / Nurse
Child with no intravenous access: glucagon 0.5 mg IM if under 25 kg or under 8 years, or 1 mg IM if 25 kg or over, followed by intravenous glucose once access is obtained.Doctor / Nurse
Thiamine 100 mg by slow intravenous injection (or intramuscularly if there is no line) with or immediately after the glucose in any malnourished or alcohol-dependent patient, because a glucose load in thiamine deficiency can precipitate Wernicke's encephalopathy — but never delay the glucose to find it.Doctor / Nurse
Once above 4.0 mmol/L, alert and swallowing safely: give 20 g of long-acting carbohydrate — a slice of bread, two biscuits, a sandwich, or the next meal if due — the step most often omitted and the one that prevents relapse.
Sulphonylurea or long-acting insulin as the agent: admit for glucose support and observation for up to 48 hours (longer in renal impairment) on a titrated 10% glucose infusion with hourly then two-hourly capillary glucose, measure creatinine, and add octreotide 50–100 micrograms subcutaneously every 6–12 hours as the specific adjunct.Doctor / NurseNot available at your setup — Infusion pump, Renal function (creatinine/urea).

Caution— what harms

Never force oral carbohydrate or gel into a drowsy, fitting or uncooperative patient, because aspiration converts a five-minute problem into a lethal one.
Never wait for a laboratory glucose before treating, and never accept a label of stroke, drunkenness, post-ictal state, dementia or psychiatric illness without a documented glucose.
Never refer for thrombolysis without a documented glucose: hypoglycaemic hemiparesis with an extensor plantar response resolves completely on correction.
Benzodiazepines are not the treatment for a hypoglycaemic seizure: the glucose is the anticonvulsant, and benzodiazepines deepen the coma without correcting the cause.
Glucagon fails where there is no glycogen — undernutrition, prolonged fasting, severe liver disease, advanced alcohol use and repeated recent episodes — so give intravenous glucose in these patients.
Glucagon is hazardous after oral glucose-lowering therapy: it stimulates insulin secretion, so in sulphonylurea poisoning it produces a transient rise followed by a deeper fall.
Do not over-treat: excess oral carbohydrate produces rebound hyperglycaemia, and in sulphonylurea poisoning a glucose load further stimulates the primed beta cell and provokes rebound hypoglycaemia.
50% glucose is highly hypertonic: it thromboses veins and causes severe tissue necrosis if it extravasates, so use 20% or 10% whenever available and never give 50% to a child.
The meter tells you to treat, never that you may stop: bedside meters and continuous glucose monitors are calibrated over roughly 3.3–8.9 mmol/L (60–160 mg/dL) and may differ from the laboratory by as much as 20% below 3.3 mmol/L.
Beware falsely low readings: poor digital perfusion gives falsely low fingerstick values, and a plain rather than fluoride-oxalate tube allows in vitro glycolysis and a falsely low laboratory glucose.
A patient who wakes, eats and feels well after a sulphonylurea is not cured: the tablet is still working for up to 48 hours and longer in renal impairment, and deaths in this group are deaths of premature reassurance rather than of inadequate initial treatment.
Failure to wake within about 10 minutes of a documented glucose above 4.0 mmol/L means a second diagnosis — cerebral oedema, post-ictal state, stroke, head injury, intoxication, sepsis, hepatic encephalopathy or adrenal crisis.
Do not skip the monitoring: hourly then two-hourly capillary glucose while any infusion runs, cardiac monitoring and a 12-lead ECG in any Level 3 episode, core temperature with rewarming of the hypothermic patient, and creatinine after a sulphonylurea.
Do not stop at the glucose: hypoglycaemia is often the marker of sepsis, hepatic or renal failure, severe malaria or adrenal crisis, and omitting the 20 g of long-acting carbohydrate or discharging without reviewing the insulin regimen (reduce the next dose by 10–20% where the reason is unclear) invites the next episode.

Refer / escalate

Escalate or transfer urgently if consciousness does not return within about 10 minutes of a documented glucose above 4.0 mmol/L (there is a second diagnosis), or if the agent is a sulphonylurea, a long- or intermediate-acting insulin or a deliberate overdose, or there is coma, seizure, focal deficit, hypothermia, malnutrition, critical illness, recurrence despite treatment, no identifiable cause, or any hypoglycaemic neonate or child in whom the cause is not obvious.

The card — assess, manage, caution

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