🧠 Locked-In Syndrome (LIS) results from damage to the brainstem, particularly the ventral pons.
It presents with a spectrum of severity, from partial to complete forms.
📖 First described by Plum and Posner in 1966.

🔑 Key concept: LIS is characterised by quadriplegia + anarthria but preserved consciousness and vertical eye movements → "conscious but trapped."

🔬Anatomy

🦵 Bilateral ventral pons damage → quadriparesis.
🙂 Facial and bulbar paralysis are common (loss of speech/swallowing).
👀 Vertical eye movements and blinking are usually preserved (midbrain intact); lateral gaze is lost.
🧍 Awareness and consciousness remain intact despite profound motor deficits.
Other deficits depend on associated injuries → blindness, ataxia, or sensory changes.

🧬 Aetiology

Most common: ⛏️ Pontine stroke (ischaemic/haemorrhagic) from basilar artery perforator occlusion.
Other causes:
- ⚡ Central pontine myelinolysis (rapid Na⁺ correction).
- 🧬 Demyelination (e.g. Multiple Sclerosis).
- 🧓 Advanced Motor Neurone Disease (ALS).
- 🎗️ Tumours compressing the ventral pons.
- 🛡️ Guillain-Barré (severe, mimicking LIS).
- 💪 Myasthenia gravis (fulminant form).
- 🤕 Trauma to brainstem.

🩺 Clinical Features

🛌 Often emerges after coma → patient regains consciousness but is quadriplegic.
👁️ Horizontal gaze palsy; vertical gaze and blinking usually intact → primary mode of communication.
🗣️ Speech absent (mute), but comprehension preserved.
🦵 Quadriparesis varies depending on corticospinal tract damage.
👓 Vigilance: eye movements inconsistent, small, and fatiguable.
🧠 Cognition: usually preserved, with only mild deficits if any.

📝 Exam pearl: LIS ≠ coma. In LIS, the patient is awake and aware but cannot move or speak. Vertical eye movement is the diagnostic clue.

🔎 Investigations

🩻 CT: Useful for excluding haemorrhage but may miss brainstem infarcts.
🧲 MRI: Gold standard for identifying pontine lesions.
📉 EEG: Demonstrates wakefulness and rules out diffuse cortical dysfunction.

💊 Management

⚡ Acute: Depends on cause.
- 🧩 Basilar artery occlusion → consider urgent thrombectomy.
- Electrolyte derangements → correct carefully.
🏥 Supportive / Long-term:
- PEG feeding due to bulbar dysfunction.
- Respiratory support in acute phase (prevent aspiration pneumonia).
- Early physiotherapy and communication training (e.g. eye-tracking devices).
❤️ Many chronic LIS patients report meaningful quality of life. Requests for euthanasia are rare.
⚖️ Patients must be supported to live with dignity, with access to rehab, pain control, and autonomy in end-of-life decisions.

🌟 Clinical takeaway: Always distinguish LIS from coma or persistent vegetative state. Early recognition, supportive care, and communication aids are key to preserving dignity and quality of life.

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Locked in Syndrome

Introduction

🔬Anatomy

🧬 Aetiology

🩺 Clinical Features

🔎 Investigations

💊 Management

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