Syringomyelia (‘syrinx’ for short) describes a collection of cerebrospinal fluid within the spinal cord - selectively affects the spinothalamic tracts

Syringobulbia is a similar phenomenon in which there is a fluid-filled cavity within the medulla of the brainstem. This is often an extension of the syringomyelia but in rare cases can be an isolated finding.

Causes include:

• a Chiari malformation: strong association
• trauma
• tumours
• idiopathic

Features

• a ‘cape-like’ (neck, shoulders and arms)
  • loss of sensation to temperature but the preservation of light touch, proprioception and vibration
  • classic examples are of patients who accidentally burn their hands without realising
  • this is due to the crossing spinothalamic tracts in the anterior commissure of the spinal cord being the first tracts to be affected
• spastic weakness (predominantly of the lower limbs)
• neuropathic pain
• upgoing plantars
• autonomic features:
• Horner’s syndrome due to compression of the sympathetic chain, but this is rare
  • bowel and bladder dysfunction
• scoliosis will occur over a matter of years if the syrinx is not treated

Investigations

• full spine MRI with contrast to exclude a tumour or tethered cord