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Hypoglycaemia: recognising it and the nursing response, conscious and unconscious

  • Assessment

A sudden change in behaviour in a person with diabetes is a low until proven otherwise: check glucose and start the protocol.

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What it is

Hypoglycaemia is a blood glucose below the threshold the institution's protocol defines. Guidelines grade it in three levels: level 1 is a low value that needs attention, level 2 is a clinically important low that needs immediate treatment, and level 3 is a severe event in which the person needs another person's help to recover, whatever the number. In hospital, each institution must have a standard, nurse-initiated treatment protocol, so the nurse can act at once without waiting for an order. The response depends on whether the patient can swallow safely: a fast-acting carbohydrate by mouth if the patient is awake and can swallow; if not, nothing by mouth, and glucagon or IV dextrose as the protocol states.

Reference values

  • Level 1: low value; level 2: clinically important low that needs immediate treatment; level 3: severe event that needs another person's help, with no fixed value. The numeric thresholds are those of the institutional protocol.
  • Early (autonomic) signs: shaking, sweating, fast heartbeat, hunger, anxiety, tingling of the lips or tongue.
  • Signs of a more severe low: confusion, irritability, poor coordination, drowsiness, odd behaviour, seizures, loss of consciousness.
  • Usual causes: insulin or a sulfonylurea with a late, missed or small meal; vigorous exercise; alcohol without food; a stopped feed; a lower steroid dose.

What you need

  • Glucose meter and supplies; the institution's hypoglycaemia protocol.
  • A fast-acting carbohydrate on the unit; glucagon and IV dextrose as the protocol provides.
  • IV access if the patient already has one.

How to measure it (and why)

  1. Suspect a low with sweating, shaking, confusion or a sudden change in behaviour: early action prevents seizures and injury.
  2. Check capillary glucose at once; if no meter is at hand and the patient is awake, treat first: the risk of waiting is greater.
  3. Check whether the patient is awake and can swallow safely: this decides the route of treatment.
  4. Awake: give the fast-acting carbohydrate the protocol states; liquids act faster than solid food.
  5. Not awake or cannot swallow: nothing by mouth (risk of aspiration); call for help and give glucagon or IV dextrose per protocol.
  6. Place an unconscious patient on their side: glucagon can cause vomiting and this protects the airway.
  7. Recheck glucose after about 15 minutes and repeat the treatment if still low: symptoms should improve within 10–15 minutes.
  8. When the patient can swallow, give a snack or the next meal: the effect of the sugar is short.
  9. Tell the doctor, record the episode and the cause, and pass it on at handoff: the insulin plan may need to change.

How to read it

  • Symptoms that improve after the carbohydrate confirm a low even if no glucose was measured.
  • A low repeated at the same time of day points to the insulin or the meal timing: report the pattern.
  • No warning signs (hypoglycaemia unawareness) is more common with long-standing diabetes, frequent lows and beta-blockers.
  • Confusion, poor coordination or drowsiness mean the low is more severe: the patient can no longer treat it alone and needs another person's help.

Next step: when to call for help

  • Call for urgent help: the patient cannot swallow, is unconscious, has a seizure or does not improve after treatment.
  • Tell the doctor: every low, even if corrected, so the plan is reviewed.
  • Tell the doctor: lows that repeat; after any low the risk of another one stays high for the next 24 hours.
  • Hand over: the episode, the cause and the closer monitoring for the next 24 hours.

Test yourself

Think of the answer, then tap the question to see it.

A patient on insulin becomes confused and sweaty before lunch. What is the first action?

Check capillary glucose at once and start the hypoglycaemia protocol. A sudden change in behaviour in a person with diabetes is a low until proven otherwise.

Why is nothing given by mouth to a patient with a low who cannot swallow?

Because of the risk of aspiration. The protocol uses glucagon or IV dextrose instead, and the patient is placed on their side.

What follows the first treatment of a low in an awake patient?

Recheck glucose after about 15 minutes, repeat if still low, then give a snack or the meal, tell the doctor and record the episode.

Which patients may have a low with few warning signs?

Older adults, people with long-standing diabetes or frequent lows, and patients taking beta-blockers.

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Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.

Sources: Nursing Pharmacology, 9.4: Antidiabetics (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2023); 16. Diabetes Care in the Hospital: Standards of Care in Diabetes—2025 (American Diabetes Association Professional Practice Committee, Diabetes Care (PMC), 2025); Guía de práctica clínica para el diagnóstico, tratamiento y seguimiento de la diabetes mellitus tipo II en la población mayor de 18 años (GPC-2015-51), versión para pacientes (Ministerio de Salud y Protección Social de Colombia, 2015); Glucagon injection (drug information) (MedlinePlus, U.S. National Library of Medicine, 2025).

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