Reduced Consciousness — Approach & Revision

1

Settle them, and check the basics

airway & glucose first

Red flags — what each should make you think

GCS ≤8airway at risk — call for help Unequal or fixed pupilsintracranial catastrophe Pinpoint pupils, low RRopioid toxicity Fever + rash / neck stiffnessmeningitis / encephalitis Focal neurologystroke or bleed Very low glucosehypoglycaemia — fix it now

🩺

Pearl

Two things first, every time: protect the airway (a GCS of 8 or less can't protect its own), and check the glucose. Hypoglycaemia is the great mimic — it can look like a stroke, a seizure or a drunk patient, and it's fixed in seconds.

Your first moves

A–EAssess A–E, protect the airwayGCS ≤8 → call anaesthetics
gluBlood glucose — immediatelytreat hypoglycaemia at once
pupPupils + GCS + focal signspinpoint → consider naloxone
✚Bloods + VBGNa, glucose, U&E, LFT, ammonia, cultures
RxGive the obvious antidoteglucose, or naloxone for opioid toxicity
CTConsider CT headfor focal signs or no clear cause

2

Run through the reversible causes

don't miss a fixable one

The causes to sweep through

Hypoglycaemia — check and correct glucose
Hypoxia / hypercapnia — oxygen, a gas
Opioids / sedatives — pinpoint pupils, low RR → naloxone
Intracranial — stroke, bleed, SAH → CT
Infection — meningitis, encephalitis, sepsis → treat, don't delay
Metabolic — sodium, DKA/HHS, hepatic or uraemic encephalopathy
Toxins, seizure (post-ictal), hypothermia

Work A–E — assess and act as you go

AAirway. A GCS of 8 or less cannot protect the airway.airway manoeuvres/adjuncts, call anaesthetics

BBreathing. Hypoxia and CO₂ retention both reduce consciousness.oxygen, gas; consider naloxone if opioid pattern

CCirculation. Shock reduces cerebral perfusion.IV access, treat shock, ECG

DDisability. GCS, pupils, focal signs, glucose. This is the core exam.correct glucose; image if focal or unexplained

EExposure. Rash, temperature (fever or hypothermia), injection marks, patches.expose and look for the cause

3

Rule out the killers

tap to open each

What points toward it, what would rule it in, and how to manage it.

points toward it

Diabetes on treatment, sweating, agitation or focal signs. Can mimic almost anything.

rule in

Low blood glucose.

manage it

Treat immediately — IV glucose or IM glucagon — then recheck. The fastest reversible cause there is.

Source: bedside glucose · local hypoglycaemia protocol

points toward it

Reduced consciousness, a low respiratory rate and pinpoint pupils.

rule in

The toxidrome and a response to naloxone.

manage it

Support ventilation; naloxone titrated to breathing. Watch for re-sedation as it wears off.

Source: TOXBASE · naloxone

points toward it

Focal neurology, a sudden severe headache, unequal pupils, or signs of raised intracranial pressure.

rule in

CT head.

manage it

Urgent imaging and referral to stroke or neurosurgery; protect the airway and maintain perfusion.

Source: CT head · stroke / neurosurgery

points toward it

Fever, headache, neck stiffness, rash, or altered behaviour and seizures (encephalitis).

rule in

Lumbar puncture (after CT if indicated).

manage it

Don't delay — IV ceftriaxone and IV aciclovir if encephalitis is suspected; dexamethasone.

Source: NICE NG240 — meningitis

points toward it

Sodium disturbance, DKA or HHS, hepatic or uraemic encephalopathy, or endocrine crises.

rule in

Bloods and a gas — glucose, sodium, ketones, urea, LFTs, ammonia.

manage it

Treat the specific derangement per local protocol; correct sodium cautiously and involve seniors.

Source: bloods · VBG · local protocols

4

Investigate — what to order, when, and what it tells you

test with a question in mind

Glucose & VBG

When

Immediately, in everyone.

Tells you

Hypoglycaemia, acid-base, CO₂, lactate, sodium.

Bloods

Send

U&E, LFT, calcium, ammonia, FBC, CRP, cultures if febrile.

Consider

Timed paracetamol/salicylate if overdose possible.

CT head

When

Focal signs, trauma, or no clear reversible cause.

Tells you

Bleed, stroke, mass, hydrocephalus.

Further tests

LP

If CNS infection suspected (after CT).

ECG

Arrhythmia, and toxicological clues.

5

How the plan comes together

disposition · handover

reversed

A clear reversible cause treated (e.g. hypoglycaemia, opioids) with full recovery and safe observation.

Then: treat the underlying issue and safety-net.

admit / escalate

Persisting reduced GCS, an airway concern, or a serious cause → admit; critical care/anaesthetics for airway protection.

Hand over: GCS trend, glucose, pupils, what you've excluded and what's still open.

🩺

Pearl

Work it like a checklist of reversibles while you protect the airway — glucose, oxygen, opioids, then image and treat. The fixable causes are quick wins you never want to miss. Nicely done getting here.