Conus medullaris syndrome

Background

Epidural compression syndromes

• Spinal cord compression (non-traumatic)
• Cauda equina syndrome
• Conus medullaris syndrome
• Epidural abscess (spinal)
• Epidural hematoma (spinal)

Clinical Features

Epidural compression syndromes table

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

• Spine related
  • Acute ligamentous injury
  • Acute muscle strain
  • Disk herniation (Sciatica)
  • Degenerative joint disease
  • Spondylolithesis
  • Epidural compression syndromes
    • Spinal cord compression (non-traumatic)
    • Cauda equina syndrome
    • Conus medullaris syndrome
    • Epidural abscess (spinal)
    • Epidural hematoma (spinal)
  • Spinal fracture
  • Cancer metastasis
  • Spinal stenosis
  • Transverse myelitis
  • Vertebral osteomyelitis
  • Ankylosing spondylitis
  • Spondylolithesis
  • Discitis
• Renal disease
  • Kidney stone
  • Pyelonephritis
  • Nephrolithiasis
• Intra-abdominal
  • Abdominal aortic aneurysm
  • Ulcer perforation
  • Retrocecal appendicitis
  • Large bowel obstruction
  • Pancreatitis
• Pelvic disease
  • PID
• Other
  • Retroperitoneal hemorrhage/mass
  • Meningitis

Spinal Cord Syndromes

• Complete spinal cord transection syndrome
• Anterior cord syndrome
• Central cord syndrome
• Brown-Sequard syndrome
• Epidural compression syndromes
  • Syringomyelia
  • Spinal cord compression (non-traumatic)
  • Cauda equina syndrome
  • Conus medullaris syndrome
  • Epidural abscess (spinal)
  • Epidural hematoma (spinal)

Evaluation

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

Management

• Dexamethasone: at least 16 mg IV as soon as possible after assessment
• Consult spine service
• Consider foley for bladder decompression

See Also

• Epidural compression syndromes

References

Authors

Ross Donaldson, Daniel Ostermayer, Neil Young