EpistemisDissociated anesthesia
Specialty: Neurology.
Why it occurs
- Syringomyelia (centromedullary cystic cavity that compresses the fibers of the anterior spinothalmic bundle that cross the anterior white commissure, losing thermal and pain sensitivity with preservation of proprioceptive and fine touch)
- Brown-Séquard syndrome (injury of a spinal hemicord that causes ipsilateral proprioceptive loss and contralateral thermoalgesic loss)
- Previous spinal artery syndrome (spinal cord infarction that spares the posterior cords, producing paralysis and thermoalgesic hypoesthesia with normal proprioception)
- Tabes dorsalis (neurosyphilis, with loss of proprioceptive and vibratory sensitivity with respect to thermoalgesics)
Initial workup
Comprehensive sensory neurological examination comparing pain perception (prick), temperature (hot and cold water tubes), vibration (128 Hz tuning fork) and proprioception (joint position); magnetic resonance imaging (MRI) of the entire cervical and thoracic spine, as well as the craniocervical junction (exclusion of Chiari malformation frequently associated with syringomyelia).
red flags
Dissociated loss of thermoalgesic sensitivity in the chest and arms associated with progressive muscle weakness in the hands, bilateral thenar atrophy and urinary incontinence, indicating progressive syringomyelia or centralmedullary tumor with compression of the pyramidal tract.
Standard management
- There are no specific drugs for sensory dissociation
- Surgical decompression of the posterior fossa or placement of a syringosubarachnoid shunt if the syringomyelia is progressive and structurally correctable
- Symptomatic management of neuropathic pain associated with gabapentinoids.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Neurology
- Listed causes
- 4
- Treatment options
- 3