AKT · Neurology/Cord & peripherallow yield

Syringomyelia

Fluid-filled cavity (syrinx) within the spinal cord

Overview

A fluid-filled cavity (syrinx) expanding within the central spinal cord, often cervical and frequently associated with a Chiari I malformation. As it expands it first interrupts the decussating spinothalamic fibres, producing a classic DISSOCIATED sensory loss in a "cape" distribution — loss of pain/temperature with preserved light touch/proprioception.

Recognise

DISSOCIATED sensory loss: loss of PAIN and TEMPERATURE with PRESERVED light touch/vibration/proprioception, in a "cape"/shawl distribution over the arms and upper trunk
Painless burns/injuries to the hands (loss of protective pain sensation); wasting/weakness of the small hand muscles as it enlarges
Associations: Chiari I malformation, prior trauma, tumour; may extend to the brainstem (syringobulbia)

Red flags

Progressive cord signs, brainstem involvement (syringobulbia), or a causative Chiari/tumour → neurosurgical referral

Differentials & how to tell them apart

Multiple sclerosisdemyelinating episodes disseminated in time/space, MRI plaques — not a central cape dissociated sensory loss

Anterior spinal artery infarctionacute onset, bilateral spinothalamic loss with motor loss but dorsal columns spared — syringomyelia is chronic and progressive

Subacute combined degeneration (B12)dorsal column + corticospinal loss (proprioception affected) — the opposite sensory pattern

Cervical spondylotic myelopathycompressive, mixed signs, no cape dissociated pattern

Investigations

MRI of the whole spine and craniocervical junction (the syrinx + any Chiari malformation/tumour). Neurosurgical assessment.

Management

MRI + neurosurgical referral (treat the cause, e.g. Chiari decompression)

1Image the whole spine/craniocervical junction (MRI) and refer to neurosurgery; treat the underlying cause (e.g. foramen magnum decompression for Chiari I, or address a tumour).Gate: A DISSOCIATED sensory loss (pain/temperature lost, light touch/proprioception preserved) in a cape distribution localises to the CENTRAL cord (syrinx) — this pattern, with painless burns of the hands, distinguishes it from a dorsal-column or peripheral lesion and points to MRI + neurosurgery
2Supportive care (protect insensate skin, neuropathic-pain management); monitor for progression/syringobulbia.

Neurosurgical treatment of the cause — e.g. foramen magnum decompression for a Chiari malformation; drainage/shunt of the syrinx

Supportive — protect insensate hands; manage neuropathic pain

Key points

Cape-distribution dissociated sensory loss + painless hand burns + small-muscle wasting = syringomyelia (often with Chiari I). The dissociation (pain/temp lost, touch/proprioception kept) is the localising key.

Monitor & prognosis

Progression of cord signs; post-operative syrinx size.

Variable; surgery can halt progression, deficits may persist.

Source: ABN; neurosurgical guidance