⚠️ If the cause of coma is uncertain (e.g. CT negative), always consider giving the CAND bundle: 💉 Cefotaxime (meningitis cover), 💊 Aciclovir (HSV encephalitis), 💉 Naloxone (opiates), 🍬 Dextrose ± Pabrinex (thiamine, prevent Wernicke’s).
This covers the major reversible causes until further information is available.

🛠️ Coma Management Overview
🔄 Initial assessment: ABC, high-flow O₂, recovery position. If GCS < 9, seek anaesthetic review and prepare for intubation. 🖥️ Early CT head (and C-spine if trauma). Exclude SDH, EDH, ICH, tumour. 🧠 If CT shows bleed or mass → urgent neurosurgery referral. 🧩 If CT is normal → think metabolic, infective, toxic, endocrine causes: 💊 Opiates: Pinpoint pupils, low GCS → IV Naloxone 0.4 mg, repeat to max 2 mg. 🍬 Hypoglycaemia: IM Glucagon 1 mg and/or IV Dextrose (200 ml 10-20% or 50 ml 50%). 🦠 Meningitis: IV Cefotaxime immediately. 🧬 HSV encephalitis: IV Aciclovir 10 mg/kg q8h. 🧪 Endocrine: Suspected Addisonian crisis → Hydrocortisone 100 mg IV stat. 🌡️ Thyroid crisis: Consider IV T3/T4 for myxoedema coma (bradycardia, hypothermia). 🧲 Seizure (Convulsive and non convulsive): Lorazepam 2-4 mg IV, see Status, EEG if uncertain. 🦟 Cerebral malaria: Travel history? → IV Quinine, blood films. ⬆️ Raised ICP and coning: Intubate + hyperventilate (target pCO₂ 28–32 mmHg). IV Mannitol boluses if appropriate. Definitive neurosurgery (EVD, decompression, clot evacuation).

🛠️ Coma Management Overview

🔄 Initial assessment: ABC, high-flow O₂, recovery position. If GCS < 9, seek anaesthetic review and prepare for intubation.
🖥️ Early CT head (and C-spine if trauma). Exclude SDH, EDH, ICH, tumour.
🧠 If CT shows bleed or mass → urgent neurosurgery referral.
🧩 If CT is normal → think metabolic, infective, toxic, endocrine causes:

💊 Opiates: Pinpoint pupils, low GCS → IV Naloxone 0.4 mg, repeat to max 2 mg.
🍬 Hypoglycaemia: IM Glucagon 1 mg and/or IV Dextrose (200 ml 10-20% or 50 ml 50%).
🦠 Meningitis: IV Cefotaxime immediately.
🧬 HSV encephalitis: IV Aciclovir 10 mg/kg q8h.
🧪 Endocrine: Suspected Addisonian crisis → Hydrocortisone 100 mg IV stat.
🌡️ Thyroid crisis: Consider IV T3/T4 for myxoedema coma (bradycardia, hypothermia).
🧲 Seizure (Convulsive and non convulsive): Lorazepam 2-4 mg IV, see Status, EEG if uncertain.
🦟 Cerebral malaria: Travel history? → IV Quinine, blood films.

⬆️ Raised ICP and coning:
- Intubate + hyperventilate (target pCO₂ 28–32 mmHg).
- IV Mannitol boluses if appropriate.
- Definitive neurosurgery (EVD, decompression, clot evacuation).

🛌 Recovery Position

📏 Assessment of Coma: GCS & Pupils

📄 Download GCS Chart

🧠 Pathophysiology of Coma (ARAS)

Consciousness requires intact Ascending Reticular Activating System (ARAS) + cortex.
ARAS = brainstem nuclei → thalamus → cortex.
Coma occurs with ↑ ICP, bilateral cortical/thalamic damage, or brainstem dysfunction.
Pupils give localising clues: 🔴 Bilateral dilated, fixed → herniation/brainstem failure. 🔵 Pinpoint → pons or opioids. ⚖️ Unequal → structural lesion compressing CN III.

🧩 Consciousness depends on ARAS (midbrain/pons) + both cerebral hemispheres. Structural lesions or diffuse metabolic insults can both produce coma.

🧪 Differential Diagnosis: CT & Glucose First

Cause	Clues	Management
🍬 Hypoglycaemia	Low CBG	IV Dextrose
💊 Opiate toxicity	Pinpoint pupils	IV Naloxone
🧠 Stroke	Focal neurology	CT head, stroke pathway
⚡ Post-ictal	History of seizure	Recovery position, treat status
🦠 Meningitis/Encephalitis	Fever, neck stiffness	Cefotaxime + Aciclovir
☠️ CO poisoning	Exposure, headache, cherry-red skin	100% O₂ ± hyperbaric
🤕 Head injury	History of trauma	CT head/C-spine
💧 Hyponatraemia	Na <115, seizures	Hypertonic saline
🧬 Sepsis	Fever, shock	IV Tazocin + Gentamicin
📟 NCSE	Unresponsive, subtle eye movements	EEG, Lorazepam
💥 SDH/EDH	Head trauma	Neurosurgery + Mannitol
🦟 Cerebral malaria	Travel history	IV Quinine

⚡ Pupils in Coma

Pupil Type	Description	Causes
Normal	3–4 mm, reactive	Metabolic causes
Thalamic	~2 mm, reactive	Thalamic compression
Fixed dilated	>7 mm, unreactive	Herniation, CN III compression
Midsized fixed	~5 mm, unreactive	Midbrain lesion
Pinpoint	1–1.5 mm, minimal reaction	Pons, opioids, organophosphates
Asymmetric	Anisocoria	Structural lesion, CN III palsy

🚨 Signs of Trauma

🐼 Raccoon eyes (periorbital bruising).
🎧 Battle’s sign (mastoid bruising).
🩸 Haemotympanum.
💧 CSF rhinorrhoea/otorrhoea (confirm with β-2 transferrin).
👆 Palpable depressed skull fracture.

📊 Pathophysiologic Patterns

Feature	Supratentorial	Subtentorial	Diffuse/Metabolic
Pupils	Normal or dilated with herniation	Midsized (midbrain), pinpoint (pons)	Normal/reactive; pinpoint (opiates); dilated (anticholinergics)
Eye movements	May show gaze preference	Abnormal adduction/abduction	Usually preserved unless sedated
Motor	Often asymmetric	Asymmetric (uni) or symmetric (bi)	Usually symmetric

📚 Teaching Commentary

Coma is a syndrome, not a diagnosis. Always think structural vs metabolic. 🔍 Pupils are the fastest localising sign: normal = metabolic, abnormal = structural. 🇬🇧 In UK practice, juniors should remember: “CAND for coma if CT is normal” → Cefotaxime, Aciclovir, Naloxone, Dextrose + Pabrinex. This covers the major reversible killers until more is known. GCS < 8 = intubate. Always immobilise the neck if trauma suspected.

References

Cases — Coma (Reduced GCS)

Case 1 — Hypoglycaemia: A 58-year-old man with type 2 diabetes on insulin is found unresponsive at home. Capillary glucose is 1.8 mmol/L. GCS 6/15. Pupils equal and reactive. After IV 20% dextrose, consciousness improves rapidly. Teaching point: Always check glucose in any unconscious patient (“D” in ABCDE). Hypoglycaemia is a reversible cause of coma, with rapid recovery if treated promptly. 🍬
Case 2 — Traumatic brain injury: A 22-year-old motorcyclist is brought in after a high-speed collision. He has unequal pupils (left fixed and dilated), GCS 5/15, and irregular breathing. CT shows an acute left extradural haematoma with midline shift. Teaching point: Low GCS after trauma should prompt urgent neuroimaging. Extradural haematomas may have a classic “lucid interval,” but once coma develops, urgent neurosurgical decompression is required. 🧠
Case 3 — Sepsis with encephalopathy: A 75-year-old woman with community-acquired pneumonia becomes progressively drowsy. On arrival: temp 39.5°C, BP 80/50, HR 120, GCS 7/15. She localises to pain but does not obey commands. Teaching point: Sepsis-associated encephalopathy is common in older adults; reduced GCS in this setting signals severe illness and high mortality risk. Urgent ABC resuscitation, antibiotics, and source control are priorities. 🌡️

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The unconscious (comatose) patient