Makindo Medical Notes

Related Subjects: |Syringomyelia |Syringobulbia |Dandy Walker syndrome

Syringomyelia is a chronic, progressive neurological condition characterized by the formation of a fluid-filled cavity or cyst, known as a syrinx, within the spinal cord. This cavity can expand over time, leading to damage to the spinal cord and disruption of the normal flow of cerebrospinal fluid (CSF). The condition can result in a range of neurological symptoms depending on the location and extent of the syrinx.

Dark pool without drain
Fingers burned, lost sense of pain
Cored out spinal cord
Named for nymph turned hollow reed
Neurosurgery in need
@DrCindyCooper

About

• Syringomyelia presents with a shawl-like distribution of spinothalamic sensory loss, particularly affecting pain and temperature sensations while sparing other modalities such as proprioception and vibration.

Aetiology

• Developmental abnormality with an enlarged cavity in the spinal cord that typically begins in adolescence.
• May be part of other developmental structural abnormalities that affect CSF drainage, such as Arnold-Chiari malformation.
• Characterized by a lower cervical and high thoracic longitudinal cyst or syrinx in the cervical cord anterior to the central canal.
• The expanding cyst damages the area around the anterior commissure where the spinothalamic tracts cross.
• There is a gradual enlargement of the syrinx over time.
• Blockage of CSF outflow from the fourth ventricle often due to Arnold-Chiari malformation.

Causes

• Chiari Malformation: A congenital condition where brain tissue extends into the spinal canal, often leading to the formation of a syrinx.
• Spinal Cord Trauma: Injury to the spinal cord, such as from a car accident or fall, can lead to the development of a syrinx, sometimes years after the initial injury.
• Spinal Cord Tumours: Tumours within or near the spinal cord can obstruct the normal flow of CSF, leading to syrinx formation.
• Post-Infectious or Post-Inflammatory Changes: Infections, such as meningitis, or inflammatory conditions affecting the central nervous system can result in the formation of a syrinx.
• Arachnoiditis: Inflammation of the arachnoid membrane, often due to surgery, trauma, or infection, can lead to the formation of a syrinx.

Clinical Features

• Central Cord Syndrome: Characterized by dissociated sensory loss, particularly affecting pain and temperature sensations in an "onion-skin" distribution over the face, sparing the nose.
• Burns on Fingers: Loss of pain sensation can lead to unnoticed injuries and burns on the fingers.
• Central Sensory Impairment: Presents as a cape-like distribution of sensory loss over the shoulders and arms.
• Preservation of Dorsal Columns: Proprioception and vibration senses remain intact as dorsal columns are spared.
• Motor Symptoms: Lower motor neuron (LMN) weakness and muscle wasting in the hands and arms due to damage to the anterior horn of the spinal cord.
• Upper Motor Neuron (UMN) Lesions: Signs such as hyperreflexia and spasticity below the level of the syrinx.
• Autonomic Symptoms: Bladder and bowel function are usually spared.
• Horner's Syndrome: May occur due to cervical cord damage affecting sympathetic pathways.
• Facial Numbness: Involvement of the trigeminal nerve nucleus extending down to C2 can cause facial numbness.
• Syringobulbia: Extension of the syrinx into the brainstem can lead to additional symptoms such as bulbar palsy, facial, palatal, or laryngeal palsy affecting cranial nerves VII, IX, X, and XI.
• Hypoglossal Nerve Dysfunction: Wasting of the tongue due to involvement of the XII cranial nerve.
• Cerebellar Signs: If the syrinx extends into the cerebellum, symptoms like ataxia and dysphagia may occur.
• Asymmetrical Presentation: The condition can present asymmetrically, depending on the extent and location of the syrinx.

Investigations

• Magnetic Resonance Imaging (MRI): The imaging modality of choice for diagnosing syringomyelia. MRI can clearly show the syrinx within the spinal cord, assess its size and extent, and identify any associated anomalies such as Chiari malformation.
• Computed Tomography (CT) Myelography: May be used in cases where MRI is contraindicated. CT myelography provides information on CSF flow and the anatomy of the spinal cord but is less sensitive in detecting syrinx cavities.

Management

• Conservative Management: In asymptomatic or mildly symptomatic cases, regular monitoring with MRI and clinical evaluations may be sufficient.
• Surgical Intervention:
  • Decompression Surgery: Often performed in cases related to Chiari malformation to relieve pressure and improve CSF flow, potentially reducing the size of the syrinx.
  • Syrinx Shunting: A surgical procedure to drain the syrinx and prevent its expansion. Shunting can involve placing a catheter to divert CSF from the syrinx to another part of the CSF system.
  • Tumour Resection: If a spinal cord tumour is causing the syrinx, surgical removal of the tumour may be necessary to restore normal CSF flow and alleviate syrinx formation.
• Rehabilitation: Physical therapy (PT) and occupational therapy (OT) can help manage neurological deficits, improve muscle strength, and enhance mobility. Speech-language therapy (SLT) may be beneficial if bulbar symptoms are present.
• Pain Management: Medications such as analgesics or anticonvulsants (e.g., gabapentin, pregabalin) may be used to manage chronic pain associated with syringomyelia.
• Symptomatic Treatment: Addressing specific symptoms like muscle spasticity with baclofen or tizanidine can improve patient comfort and functionality.

Prognosis

• The prognosis of syringomyelia depends on the underlying cause and the extent of spinal cord damage. Early diagnosis and appropriate management, particularly surgical intervention, can help prevent further neurological deterioration and improve quality of life.
• Patients with associated Chiari malformation may experience significant improvement after decompression surgery, while those with progressive spinal cord tumours may have a more guarded prognosis.

References

• Syringomyelia - Medscape
• Syringomyelia - NIH Genetic and Rare Diseases Information Center