Myelopathy

Diseases, ,

 

Approaches:

  • Localization by level of lesion:
    • Cervical
    • Thoracic
    • Lumbar (Conus medullaris and cauda equina syndrome)
  • Localization by cross-sectional origin of pathology:
    • Extradural
    • Intradural extramedullary
    • Intramedullary (within the spinal cord)
  • Anatomical syndromes
    • Anterior cord syndrome
    • Central cord syndrome
    • Transverse myelitis
    • Brown-Sequard syndrome

 

Anatomical syndrome approach:

Anterior cord syndrome:

  • Anatomy: lesion at anterior aspects of the spinal cord. Involves corticospinal tracts, spinothalamic tract and bowel and bladder dysfunction.
  • Clinical features: Severe weakness, loss of pinprick and fine sensation, bowel and bladder dysfunction. Intact proprioception and vibration.
  • Etiology: usually spinal cord infarction.

Central cord syndrome:

  • Anatomy:  lesions at the central structures in the spinal cord. Damage to crossing spinothalamic tract fibres, corticospinal tract.
  • Clinical features: weakness in the hands much more than the legs, suspended sensory level to pin-prick, and loss of sensation lower to the level,
  • Etiology: trauma is the most common cause, syringomyelia can cause similar symptoms

Transverse myelopathy:

  • Anatomy: lesions at the anterior and posterior aspects as well as right and lateral aspects of the spinal cord. Damage to corticospinal tract, spinothalamic tract, dorsal column tract, bowel and bladder fibers.
  • Clinical features: Partial or complete dysfunction. weakness, sensory loss in all modalities, bowel and bladder dysfunction.
  • Etiology: many causes including immune, infectious, trauma etc.

Brown-Sequard syndrome:

  • Anatomy: lesions at half (side) of the spinal cord. Damages the ipsilateral corticospinal tract, ipsilateral dorsal column tract, contralateral spinothalamic tract,
  • Clinical features: ipsilateral weakness, contralateral pin-prick sensation loss, ipsilateral paraesthesia,
  • Etiology: rare, Radiation myelopathy, penetrating puncture trauma (very rare),

Conus medullaris syndrome:

  • Anatomy: lesions in the lower terminal part of the spinal cord. Damage to structures controlling bowel and bladder sphincters. May interrupt motor fibers and sensory fibers
  • Clinical features: bowel and bladder sphincter dysfunction, with back pain, saddle anesthesia, erectile dysfunction, less commonly weakness in the legs (usually more symmetric than cauda equina syndrome when present)
  • Etiology: tumors, lumbar intervertebral disc central herniation,

Cauda equina syndrome:

  • Anatomy: lesion at the nerve roots in the cauda equina (lower than end of the spinal cord proximal to exiting the spinal canal and thecal sac)
  • Clinical features: asymmetric painful lumbar polyradiculopathy, Asymmetric weakness (lower motor neuron pattern), painful polyradiculopathy, bowel and bladder sphincter dysfunction
  • Etiology: lumbar intervertebral disc herniation, lumbar spinal stenosis, epidural abscess, metastatic tumors, ankylosing spondylitis, trauma, spinal bifida,

 

Causes of myelopathy:

Spinal cord compression:

  • Herniated intervertebral disc
  • Tumor
  • Vertebral fracture

Vascular myelopathy:

Inflammatory i.e. Acute  myelitis:

Infectious myelopathy:

  •  Mycoplasma pneumonia, syphilis, HSV-1, HIV-1, HTILV,

Radiation induced myelopathy and radiation induced spinal cord hemorrhage
Neoplastic:

  • Extradural neoplasms:
    • Metastatic to vertebral column: Lung, breast, prostate
    • Primary vertebral column neoplasms
  • Intradural extramedullary neoplasms:
    • Schwannoma
    • Neurofibroma
    • Carcinomatous meningitis (usually don’t present as myelopathy, more often polyradiculopathy)
  • Intramedullary (within the spinal cord):

 

Investigations to consider:

MRI spine:

  • Assesses compressive myelopathy, assesses for pattern length & enhancement, abscess, features of specific diagnosis, cord expansion in tumors & abscess, flow voids in AVMs

CSF analysis including:

  • Cell count with differential, glucose, protein
  • IgG index, oligoclonal bands,

B12, Methylmalonic acid levels
Vitamin E levels, Copper levels
Infectious Investigations to consider::
Bacteria:

  • Syphilis serology & CSF VDRL
  • Lyme serology i.e. Borrelia burdorferi serology
  • Tests for Brucella spp. (Brucellosis),
  • Mycoplasma pneumoniae  & cold agglutinins
  • Mycobacterium tuberculosis TB
  • Yersinia enterocolitica,
  • Chlamydiae psittaci, (psittacosis)
  • Rachalimaea henselae (cat scratch fever)

Viral testing:

  • HIV tests, HTLV 1 tests,
  • PCR: HSV, VZV, EBV
  • VZV antibodies
  • EBV, CMV, HHV6,
  • Enteroviruses, lymphocytic choriomeningitis virus LCM, Influenza virus
  • Echovirus, coxsackie virus, hepatitis A, hepatitis B, rubella, measles, mumps
  • Poliomyelitis, West Nile Virus WNV: +/- LMN signs

Fungal: Cryptococcus testing
Parasitic:

  • Schistosomiasis tests (serology & stool)
  • Toxaplasma gondii Toxoplasmosis
  • Cysticercosis
  • Toxocariasis, gnathostoma, angiostrongyllus

Autoimmune Investigations to consider::

  • Anti-NMO antibody: neuromyelitis optica
  • SS-A & SS-B, antiphopholipid antibodies,
  • Lip biopsy: Sjogren syndrome
  • ACE levels
  • Only if clinically indicated (not routine) consider coeliac antibodies
  • Stiff person syndrome: anti-GAD65, anti-amphiphysin, anti-gephyrin

Very Long Chain Fatty Acids: adrenoleukodystrophy
Mitochondrial disease: lactate, muscle biopsy, mitochondrial DNA analysis

Monitor:

Urodynamics: neurogenic bladder
Screening or osteoporosis
Autonomic dysreflexia: an episode of extremely high BP or increase of or >20mmHg above patients baseline. Headache & flushing may also occur. Note: this occurs in lesions above T5

Treatment:

Treat the underlying cause
Consider empiric therapy for inflammatory, viral or bacterial causes while tests are pending

General measures for myelopathy:

Monitor & support respiratory function
Monitor & treat neurogenic shock
Monitor & treat constipation
Monitor & treat for neurogenic bladder
Monitor & treat erectile dysfunction
Monitor & treat osteoporosis
Monitor & treat spasticity:

  • Baclofen, diazepam, dantrolene or tizanidine P.O.
  • 2nd line: Baclofen intrathecally

Prevent joint contractures:

  • Physical therapy & mobilisation

Treat neuropathic pain
Skin care: Monitor, prevent & treat pressure sores
If autonomic dysreflexia occurs:

  • Removal of noxious stimulus e.g.
  • Bladder drainage (insertion of or insuring function of Foley catheter),
  • Consider PR examination to rule out Fecal impaction
  • Assess skin below the level of injury
  • Sit up the patient & lower the patient’s legs
  • If BP remains high:
    • Nifedipine or nitroprusside
    • Consider clonidine for prophylaxis

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