Cord Syndromes 2018-01-30T16:37:17+00:00

Anatomy of the Spinal Cord Tracts

  • Motor:
    • Anterior horn (cell bodies of motor neurons)
    • Lateral corticospinal / pyramidal tract
      • Begins in primary motor cortex
      • Descends on ipsilateral side through thalamus, reaching the medulla
      • Crosses at medullary pyramid
      • Then descends in contralateral cord
  • Sensory:
    • Lateral spinothalamic / anterolateral tract (pain and temperature)
      • Sensory fibres enter ipsilateral cord via dorsal root
      • Immediate decussation across the anterior commissure, just anterior to the central canal
      • Thereafter ascends to thalamus in the contralateral cord
    • Dorsal column (vibration, pressure, proprioception)
      • Ipsilateral on entering cord, ascends on ipsilateral side to ipsilateral cuneate and gracilis nuclei
        • Fasciculus cuneatus – upper limb
        • Fasciculus gracilis – lower limb
      • Second order neurons from these nuclei then decussate and run towards the thalamus (ventral posteromedial nucleus)

Segmental Syndromes / Transverse Myelitis

  • Acute cord transection will cause spinal shock (flaccid paraparesis, urinary retention, diminished reflexes)
  • Thereafter, clinical picture is:
    • Sparing of the cranial nerves
    • Increased tone (velocity-dependent)
    • Hyperreflexia below the level of the lesion
    • Upgoing plantars
    • Power
      • If mechanical, may have LMN weakness at the level of lesion
      • Otherwise, pyramidal weakness bilaterally below the level of lesion
    • Sensation
      • Sensory level in a dermatomal distribution
      • Both pinprick and temperature affected
    • Look for wheelchair
    • Look for surgical scars over the back
  • Causes
    • Trauma
    • Transverse myelitis
      • Demyelinating
        • Multiple sclerosis
        • Neuromyelitis optica
        • Idiopathic transverse myelitis
        • Acute disseminated encephalomyelitis
      • Inflammatory
        • Systemic lupus erythematosus
        • Sjögren’s syndrome
      • Infection
        • Bacterial: Lyme, mycoplasma, tuberculosis, syphilis
        • Viral: HSV, VAV, CMV, HIV, HAV, echovirus, influenza virus
    • Tumours
    • Epidural abscess
    • Degenerative spondylosis
  • Investigation
    • Magnetic resonance imaging of the spinal cord to look for lesions separated in space
    • Lumbar puncture
      • Unpaired oligoclonal bands (MS)
      • Cytology
      • CSF VDRL
      • Elevated CSF protein
      • Angiotensin converting enzyme (neurosarcoidosis)
    • Serology
      • NMO antibody (anti-aquaporin-4 antibody) – sensitivity 70%, specificity 100%
      • Antinuclear antibody, anti-dsDNA (SLE)
      • Anti-Ro/SSA and anti-La/SSB antibodies (Sjogren’s syndrome)
  • Management (inflammatory myelitis)
    • Multidisciplinary team approach
    • Patient education
    • IV methylprednisolone
    • For severe disease
      • IV cyclophosphamide
      • Plasma exchange, especially if failed methylprednisolone
    • If no improvement after PLEX, some evidence for
      • IV immunoglopulin (ADEM)
      • Rituximab (NMO)
      • Azathioprine (SLE)
      • See section on multiple sclerosis

Posterior Cord Syndrome

  • Posterior cord syndromes affect the dorsal column and corticospinal tracts
  • Clinical findings
    • Increased tone below the level of the lesion
    • Hyperreflexia below the level of the lesion
    • Bilateral pyramidal weakness below the level of the lesion
    • Proprioceptive and vibration loss below the level of the lesion
    • Spared pinprick sensation
  • Causes
    • Multiple sclerosis (cerebellar signs, INO, RAPD)
    • Tabes dorsalis (Argyll-Robertson pupils)
    • Sub-acute combined degeneration of the cord from B12 deficiency (absent ankle jerks, macroglossia)
    • Friedrich’s ataxia (cerebellar signs, pes cavus, kyphoscoliosis)
    • Epidural / intramedullary tumours
    • Cervical myelopathy
    • Atlanto-axial subluxation

Anterior Cord Syndrome

  • Anterior cord syndromes affect the spinothalamic and corticospinal tracts
  • Clinical findings
    • Increased tone below the level of the lesion
    • Hyperreflexia below the level of the lesion
    • Bilateral pyramidal weakness below the level of the lesion
    • Loss of pain and temperature bilaterally below the level of lesion
    • Proprioception and vibration spared
  • Causes
    • Anterior spinal artery infarction
    • Intervertebral disc herniation
    • Radiation myelopathy

Brown-Sequard Syndrome

  • Hemisection of the cord affecting the corticospinal, dorsal column and spinothalamic tracts
  • Unlike most cord syndromes, this causes a hemiparesis
  • Clinical findings
    • Spares all the cranial nerves
    • Ipsilateral increased tone below the level of the lesion
    • Ipsilateral hyperreflexia below the level of the lesion
    • Ipsilateral pyramidal weakness
    • Ipsilateral loss of proprioception and vibration below the level of the lesion
    • Contralateral loss of pain and temperature below the level of the lesion
  • Causes
    • Demyelination
    • Trauma
    • Spinal cord tumours
    • Longitudinal myelitis

Central Cord Syndrome / Synringomyelia

  • Central lesions affect the decussating nociceptive fibres first, then the anterior horn cells and corticospinal tracts; the dorsal columns are usually spared
  • Clinical findings
    • Inspection
      • Wasting at the level of the lesion
      • Spasticity below the level of the lesion
    • Reflexes
      • Increased below the level of the lesion (if large enough to affect corticospinal tract)
      • May be absent at the level of the lesion
      • Plantars may be extensor
    • Power
      • Flaccid weakness at the level of the lesion (anterior horn cell)
      • Pyramidal below the level of the lesion (corticospinal tract)
    • Sensation
      • Bilateral pain and temperature loss around the level of the lesion
      • Normal pain and temperature above and below the level of the lesion
      • Normal proprioception and vibration sense
  • Causes
    • Syringomyelia
    • Intramedullary tumours

Pure Motor Syndrome (Spastic Paraparesis)

  • Clinical picture
    • Walking aids / wheelchair
    • Disuse atrophy
    • Increased tone, usually in the lower limbs first
    • Hyperreflexia
    • Pyramidal weakness below the level of the lesion
    • Sensation usually intact
      • Some forms of hereditary spastic paraplegia may involve mild dorsal column loss
  • Causes
    • Human T cell lymphotropic virus-1 (HTLV1, tropical spastic paraparesis)
      • Retrovirus which infects CD4 T cells
      • Transmission: vertical, sexual, contaminated blood products
      • Often in Africa, South America and southern Japan
      • Also causes adult T cell leukaemia / lymphoma
      • Lifetime risk of haematological or neurological events in carriers: 0.25 – 3%
      • Usual onset 40 – 50, more common in women
      • Onset usually asymmetric and gradual, with gait and urinary disturbance
      • May have brisk upper limb reflexes
    • Hereditary spastic paraplegia
      • Almost 50 gene loci
      • De novo mutations are frequent
      • May be inherited in autosomal dominant, autosomal recessive or X-linked pattern
        • Autosomal dominant is most common
      • Phenotype and penetrance is variable – determining family history may be difficult
      • Usually presents in the fourth decade (range of first till seventh decade)
      • Spastic paraparesis, usually of the lower limbs
        • 30% have dorsal column involvement
        • 30% have neurogenic bladder
    • Primary lateral sclerosis (see Motor Neurone Disease)
  • Investigation
    • Peripheral blood film
      • Atypical T lymphocytes with convoluted nuclei – “flower cells” (HTLV1)
    • HTLV1 antibodies in CSF and serum
    • Genetic testing for hereditary spastic paraparesis (most common is spastic paraplegia gene 4)
  • Management
    • Multidisciplinary team approach
    • HTLV
      • Transient improvement with corticosteroids
      • Combivir (lamivudine + zidovudine) may decrease viral load, no evidence for effect on neurological function

Conus Medullaris Syndrome

  • Lesion at L2 affecting the conus medullaris (tapered end of spinal cord)
  • Clinical picture
    • Often sudden, bilateral onset of symptoms with lower back pain
    • Normal knee jerks, but absent ankle jerks
    • Flaccid paralysis bladder and rectum
    • Saddle anaesthesia
    • Leg weakness may be mild, or predominantly distal
  • Causes
    • Epidural abscess
    • Tumour at L2
    • Intervertebral disc herniation at L1/2

Cauda Equina Syndrome

  • Compression of the cauda equina, containing 18 nerve roots (L2 – S5)
  • Clinical picture
    • Lower back pain radiating to legs
    • Wasting, usually no fasciculations
    • Arreflexia in the legs (ankles affected first)
    • Weakness
      • Ankle plantarflexion (S1/S2)
      • Knee flexion (L5/S1)
      • Hip extension (L5/S1)
      • May involve more muscle groups as compression worsens
    • Sensory loss in all modalities in dermatomes supplied by affected roots
    • May have urinary retention, lax anal tone (must do digital rectal examination)
  • Causes
    • Intervertebral disc herniation
    • Epidural abscess
    • Epidural tumor
    • Intradural extramedullary tumour
    • Carcinomatous meningitis
    • Bony metastases
  • Investigation
    • Magnetic resonance imaging of the lumbosacral spine
  • Management
    • Emergency radiotherapy
    • Steroids (dexamethasone 16mg daily in divided doses)
    • Neurosurgical referral for surgical decompression and stabilization

Cord Syndromes

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