🧠 Syringomyelia is a chronic, progressive neurological condition characterized by the formation of a fluid-filled cavity (syrinx) within the spinal cord. Over time, the syrinx may expand, damaging the spinal cord and disrupting cerebrospinal fluid (CSF) flow, leading to progressive neurological symptoms.

📖 About

Syringomyelia typically presents with a “shawl-like” or “cape-like” distribution of spinothalamic sensory loss (pain & temperature), while sparing proprioception and vibration.

🧬 Aetiology

Developmental abnormality with an enlarged cavity in the spinal cord, often starting in adolescence.
Frequently associated with Chiari I malformation (hindbrain herniation affecting CSF drainage).
Usually a syrinx in the lower cervical/high thoracic cord anterior to the central canal.
Expansion damages the anterior commissure (where spinothalamic tracts cross).
Gradual enlargement over time → progressive neurological deficits.

⚠️ Causes

Chiari Malformation: Brain tissue extends into the spinal canal, disturbing CSF flow.
Spinal Cord Trauma: Syrinx may appear months–years after injury.
Spinal Cord Tumours: Obstruct CSF flow, leading to syrinx formation.
Post-Infectious/Inflammatory: E.g. meningitis, arachnoiditis.
Arachnoiditis: Following surgery, trauma, or infection.

🩺 Clinical Features

Dissociated Sensory Loss: Cape-like loss of pain & temperature; dorsal columns spared.
Burn Injuries: Due to unnoticed painless injuries (loss of protective sensation).
Motor Symptoms:
- LMN weakness/wasting in hands & arms (anterior horn cell damage).
- UMN signs (spasticity, hyperreflexia) below syrinx level.
Horner’s Syndrome: Ptosis, miosis, anhidrosis (cervical sympathetic involvement).
Facial Numbness: From trigeminal nucleus involvement extending to C2.
Syringobulbia: If syrinx extends to brainstem → bulbar palsy, CN VII/IX/X/XI/XII palsies.
Cerebellar Signs: Ataxia, dysphagia if extension into posterior fossa.
Asymmetry: Can present asymmetrically depending on syrinx size/location.

📊 Comparison: Syringomyelia vs Syringobulbia

Feature	Syringomyelia	Syringobulbia
Definition	Fluid-filled cavity (syrinx) within the spinal cord	Fluid-filled cavity within the brainstem (medulla)
Common Association	Chiari I malformation, trauma, tumours	Chiari I malformation, extension of syringomyelia, brainstem tumours
Main Structures Affected	Spinothalamic tracts → pain & temperature loss	Cranial nerve nuclei & brainstem tracts → bulbar & cranial nerve palsies
Classic Clinical Signs	🌀 Cape-like loss of pain & temperature over shoulders/arms Weakness & wasting of hand muscles	🎭 Onion-skin facial sensory loss 🗣 Bulbar palsy (dysphagia, dysarthria) 😮 Horner’s syndrome
Cranial Nerves	Usually spared	Involvement of CN VII, IX, X, XI, XII → facial weakness, hoarseness, tongue wasting
Cerebellar Involvement	Occasional (if syrinx is large)	More likely due to brainstem–cerebellar connections → ataxia
Investigations	MRI spine	MRI brain & spine (to check medulla and extension)
Management	Posterior fossa decompression, syrinx shunting, treat cause	Posterior fossa decompression (Chiari), syrinx shunting, tumour resection if present

🧪 Investigations

MRI (Gold Standard): Clearly defines syrinx, size, and associated anomalies (e.g. Chiari malformation).
CT Myelography: If MRI contraindicated; shows CSF flow but less sensitive.

💊 Management

Conservative: Asymptomatic or mild → monitor with MRI & neuro exams.
Surgical Options:
- Posterior Fossa Decompression: For Chiari malformation-related syrinx.
- Syrinx Shunting: Diverts CSF from syrinx to reduce expansion.
- Tumour Resection: If syrinx is secondary to spinal tumour.
Rehabilitation: PT/OT for strength & function; SLT if bulbar symptoms.
Pain Control: Analgesics, gabapentin, pregabalin.
Spasticity: Baclofen or tizanidine for comfort and function.

📉 Prognosis

Highly dependent on cause & timing of treatment.
Early surgery (e.g. decompression in Chiari malformation) → good outcomes.
Tumour-related syrinx → prognosis depends on malignancy.
Untreated progressive syrinx → severe disability.

📚 References

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Syringomyelia