Makindo Medical Notes

Related Subjects: |Acute Stroke Assessment (ROSIER&NIHSS) |Causes of Stroke |Ischaemic Stroke |Cancer and Stroke |Cardioembolic stroke |CT Basics for Stroke

Introduction

• 🧠 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.