Conus medullaris syndrome

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Epidural compression syndromes

Clinical Features

Epidural compression syndromes table[1]

Syndrome Spinal cord compression Conus medullaris syndrome Cauda equina syndrome
Location of lesion Lesions at vertebral level L2
Spontaneous pain Unusual and not severe; bilateral and symmetrical in perineum or thighs Often very prominent and severe, asymmetrical, radicular
Motor findings Deficits usually affect both legs but are often asymmetric Not severe, symmetrical; rarely twitches May be severe, asymmetrical, fibrillary twitches of paralyzed muscles are common
Sensory findings Weakness in lower extremities, paresthesias/sensory deficits, gait difficultly Saddle distribution, bilateral, symmetrical, disassociated sensory loss (impaired pain and temperature with sparing of tactile) Saddle distribution (75% pts), may be asymmetrical, no dissociation of sensory loss
Reflex changes Achilles reflex may be absent Patellar and Achilles reflexes may be absent
Sphincter disturbance Bladder and rectal sphincter paralysis usually reflect involvement of S3-S5 nerve roots Early and marked (both urinary and fecal) Late and less severe (60-80% pts)
Male sexual function Impaired early Impairment less severe
Onset Sudden and bilateral Gradual and unilateral
Other Urinary retention with or without overflow incontinence (Sn 90%, Sp 95%)

Differential Diagnosis

Lower Back Pain

Spinal Cord Syndromes


  • Emergent MRI
    • If considering compression due to neoplasm obtain scan of entire spine
  • Consider Bladder scan/ultrasound for bladder volume


  1. Dexamethasone: at least 16 mg IV as soon as possible after assessment[2]
  2. Consider foley for bladder decompression
  3. Radiation therapy (if due to neoplasm)
  4. Consult spine service (neurosurgery or ortho; institution dependent)

See Also


  1. Bradley WG. Neurology in Clinical Practice: Principles of diagnosis and management. P363
  2. Metastatic spinal cord compression: Diagnosis and management of patients at risk of or with metastatic spinal cord compression. Full Guideline. November 2008. Developed for NICE by the National Collaborating Centre for Cancer. ©2008 National Collaborating Centre for Cancer