Diseases of the Spinal Cord

Diseases of the spinal cord are frequently devastating. They produce quadriplegia, paraplegia, and sensory deficits far beyond the damage they would inflict elsewhere in the nervous system because the spinal cord contains, in a small cross-sectional area, almost the entire motor output and sensory input of the trunk and limbs. Many spinal cord diseases are reversible if recognized and treated at an early stage thus, they are among the most critical of neurologic emergencies.

Treatable Spinal Cord Disorders Compressive Epidural, intradural, or intramedullary neoplasm Epidural abscess Epidural hemorrhage Cervical spondylosis Herniated disk Posttraumatic compression by fractured or displaced vertebra or hemorrhage Vascular Arteriovenous malformation Antiphospholipid syndrome and other hypercoagulable states Inflammatory Multiple sclerosis Neuromyelitis optica Transverse myelitis Sarcoidosis Sjögren-related myelopathy Systemic lupus erythematosus Vasculitis

Infectious Viral: VZV, HSV-1 and -2, CMV, HIV, HTLV-I, others Bacterial and mycobacterial: Borrelia, Listeria, syphilis, others Mycoplasma pneumoniae Parasitic: schistosomiasis, toxoplasmosis Developmental Syringomyelia Meningomyelocele Tethered cord syndrome Metabolic Vitamin B12 deficiency (subacute combined degeneration) Copper deficiency

Cervical Cord Upper cervical cord lesions produce quadriplegia and weakness of the diaphragm. Lesions at C4-C5 produce quadriplegia; at C5-C6, there is loss of power and reflexes in the biceps; at C7 weakness affects finger and wrist extensors and triceps; and at C8, finger and wrist flexion are impaired. Horner's syndrome (miosis, ptosis, and facial hypohidrosis) may accompany a cervical cord lesion at any level.

Thoracic Cord Lesions here are localized by the sensory level on the trunk and by the site of midline back pain that may accompany the syndrome. Useful markers for localization are the nipples (T4) and umbilicus (T10). Leg weakness and disturbances of bladder and bowel function accompany the paralysis. Lesions at T9-T10 paralyze the lower—but not the upper—abdominal muscles, resulting in upward movement of the umbilicus when the abdominal wall contracts (Beevor's sign).

Lumbar Cord Lesions at the L2-L4 spinal cord levels paralyze flexion and adduction of the thigh, weaken leg extension at the knee, and abolish the patellar reflex. Lesions at L5-S1 paralyze only movements of the foot and ankle, flexion at the knee, and extension of the thigh, and abolish the ankle jerks (S1).

Sacral Cord/Conus Medullaris The conus medullaris is the tapered caudal termination of the spinal cord, comprising the lower sacral and single coccygeal segments. The distinctive conus syndrome consists of bilateral saddle anesthesia (S3-S5), prominent bladder and bowel dysfunction (urinary retention and incontinence with lax anal tone), and impotence. The bulbocavernosus (S2-S4) and anal (S4-S5) reflexes are absent. Muscle strength is largely preserved. lesions of the cauda equina, the nerve roots derived from the lower cord, are characterized by low back and radicular pain, asymmetric leg weakness and sensory loss, variable areflexia in the lower extremities, and relative sparing of bowel and bladder function. Mass lesions in the lower spinal canal often produce a mixed clinical picture with elements of both cauda equina and conus medullaris syndromes

Central Cord Syndrome This syndrome results from selective damage to the gray matter nerve cells and crossing spinothalamic tracts surrounding the central canal. In the cervical cord, the central cord syndrome produces arm weakness out of proportion to leg weakness and a "dissociated" sensory loss, meaning loss of pain and temperature sensations over the shoulders, lower neck, and upper trunk (cape distribution), in contrast to preservation of light touch, joint position, and vibration sense in these regions. Spinal trauma, hydromyelia, hematomyelia, syringomyelia, and intrinsic cord tumors are the main causes.

An acute cervical central spinal cord syndrome can occur after severe hyperextension injuries of the neck. Patients with this syndrome become quadriplegic after cervical trauma but regain strength in the legs in a matter of hours or even minutes. There is bladder dysfunction, usually urinary retention, and patchy sensory loss below the level of the lesion. Weakness is more pronounced in the arms, more distal than proximal (man-in-a-barrel syndrome)

selectively damaged in subacute combined degeneration of the spinal cord owing to vitamin B12 (cobalamin) deficiency. vacuolar myelopathy associated with acquired immunodeficiency syndrome (AIDS), human T-lymphotropic virus type 1 (HTLV-1), associated myelopathy (tropical spastic paraparesis), or extrinsic cord compression (e.g., cervical spondylosis) complain of paresthesias in the feet and, less often, in the hands, difficulties with gait and balance, including loss of proprioception and vibration sense in the legs as well as sensory ataxia with a positive Romberg's sign and bladder atony. Pain and temperature sensations remain intact because of the preservation of the spinothalamic tracts. Bilateral corticospinal tract dysfunction results in spasticity, hyperreflexia, and bilateral Babinski's signs.

Tabes usually develops 10 to 20 years after the onset of luetic infection and results in impaired vibration and position sense and decreased tactile localization Patients with tabes dorsalis often complain of lancinating (lightning) pains, most frequently in the legs, develop urinary incontinence, and have absent patellar and ankle muscle stretch reflexes. The affected limbs are hypotonic but not weak, and hyperextensible joints are common. Abdominal crises, mimicking a surgical abdomen, occur in approximately 10% of patients. Laryngeal crises with stridor, rectal, and vesical crises are less common. Trophic disturbances result in Charcot joints, which are analgesic joints that disintegrate and become deformed as a result of chronic trauma. Many patients have diminished deep pain sensation demonstrated by diminished sensation to squeezing the Achilles tendon (Abadie's sign). Argyll Robertson pupils, optic atrophy, eyelid ptosis, or ophthalmoplegia

type I infantile progressive spinal muscular atrophy of Werdnig-Hoffman disease, intermediate spinal muscular atrophy or type II spinal muscular atrophy, type III juvenile progressive spinal muscular atrophy or Kugelberg-Welander disease, and progressive spinal muscular atrophy in motor neuron disease. Adult onset of spinal muscular atrophy may involve the proximal or distal musculature or have a chronic asymmetric monomelic pattern. Pure lower motor neuron syndromes have been described in cases of hexosaminidase deficiency, poliomyelitis (postpolio syndrome), and postirradiation syndrome. diffuse weakness, atrophy, and fasciculations are noted in the muscles of the trunk and extremities. Muscle tone is usually reduced and muscle stretch reflexes may be depressed or absent. Sensory changes are absent because the sensory tracts remain unaffected.

Anterior Spinal Artery Syndrome Infarction of the cord is generally the result of occlusion or diminished flow in this artery. The result is extensive bilateral tissue destruction that spares the posterior columns. The lower thoracic segment of the spinal cord and conus medullaris are most frequently involved. Patients with the anterior spinal artery syndrome have an abrupt onset, and is often associated with radicular pain. Loss of motor function (e.g., flaccid tetraplegia or paraplegia) occurs within minutes on hours below the level of the lesion (bilateral corticospinal tract damage).

There is impaired bowel and bladder control, and thermoanesthesia and analgesia below the level of the lesion (compromise of the spinothalamic tracts bilaterally). Position sense, vibration, and light touch remain intact because of the preservation of the dorsal columns (supplied by the posterior spinal arteries). Patients may develop painful burning dysesthesias below the level of cord injury, likely related in part to selective neospinothalamic deafferentation and preservation of the posterior columns

Clinical Manifestations of Spinal Cord Ischemia Anterior Spinal Artery Syndrome Back of neck pain of sudden onset Rapidly progressive flaccid and areflexic paraplegia Loss of pain and temperature to a sensory level Preservation of proprioception and vibration sensation Urinary incontinence Posterior spinal artery syndrome Loss of proprioception and vibratory sense Preserved pain and temperature sensation except for involved segment of cord, where global anesthesia is present Loss of myotatic and cutaneous reflexes below involved segment Absence of motor deficits Isolated Focal Motor or Sensory Deficits in Extremities, Which May Represent Lacunar Infarctions Slowly Progressive Paraparesis or Quadriparesis (Hypoxic Myelopathy) Spinal Cord Claudication (Hemodynamic Transient Ischemic Attacks or TIAs)

Causes of Venous Spinal Cord Infarction Thrombophlebitis Chronic meningitis Decompression sickness (Caisson disease) Acute myelogenous leukemia Spinal cord glioma Polycythemia rubra vera Esophageal vein sclerotherapy Liver abscess (embolization of venous material) Fibrocartilaginous emboli

Myelopathies Congenital Diastematomyelia (spinal notochord syndrome) Traumatic Nonpenetrating injuries Penetrating injuries Spondylogenic Craniocervical junction abnormalities Atlantoaxial anomalies (Down's syndrome) Cervical spondylotic myelopathy Cervical disc herniation with spinal cord compression Thoracic disc herniation with thoracic spinal stenosis Diffuse idiopathic skeletal hyperostosis (Forestier's disease) Ossification of the posterior longitudinal ligament Rheumatoid disease of the spine (RA) Anterior atlantoaxial subluxation Posterior atlantoaxial subluxation Vertical atlantoaxial subluxation

Cervical/Thoracic spine pachymeningitis Thoracic cord compression by rheumatoid nodules Thoracic spinal cord infarction due to vasculitis Syringomyelia due to cervical cord compression Transverse myelopathy associated with antiphospholipid antibodies Transverse myelitis due to sulfadiazine Myelopathy in SLE SLE myelopathy Transverse myelopathy associated with antiphospholipid antibodies Herpes zoster myelitis Compression fracture (long - term corticosteroid use) with spinal cord compression Spinal epidural/subdural hemorrhages Epidural lipomatosis Tuberculous spondylitis Atlantoaxial subluxation

Spondyloarthropathies Ankylosing spondylitis Reiter's syndrome Reactive arthritis Psoriatic arthritis Associated with inflammatory bowel disease Undifferentiated spondyloarthropathies Whipple's disease Behcet's disease Demyelinating Multiple sclerosis Devic's neuromyelitis optica Acute disseminated encephalomyelitis Postinfectious and postvaccinal myelopathies Inflammatory transverse myelitis

Osmotic demyelination syndrome Leukodystrophies Infectious Bacterial (tuberculosis, pyogenic infections) Viral (e.g., HIV, HTLV - 1) Parasitic (e.g., schistosomiasis, hydatid disease) Other (e.g., syphilis, Lyme disease, Mycoplasma) Granulomatous disorders Sarcoidosis Wegener's granulomatosis Vascular Vasculitis Spinal artery (anterior, posterior) occlusion Venous spinal cord infarction Vascular malformations Metabolic B 12 deficiency Copper deficiency Hyperthyroidism Diabetes mellitus

Mitochondrial disorders Spinal tumors Tumors of bone (primaryâ € “ secondary) Plasma cell dyscrasias multiple myeloma, solitary plasmacytoma Extradural (metastatic carcinoma, lymphomas, malignant melanoma) Intradural extramedullary Intramedullary (astrocytomas, glioblastoma multiforme, ependymoma, primitive neuroectodermal tumors, gangliocytoma, neurocytoma, lipoma, epidermoid cyst, meningioma) Nontumoral myelopathies Subacute necrotizing myelopathy of Foix and Alajouanine Subacute paraneoplastic necrotizing myelopathy (lung carcinoma, lymphomas) Drugs and Toxic Myelopathies Neurolathyrism Konzo (cyanogenic glucosides from bitter casava) Subacute myelo - optic neuropathy Methotrexate, Cytosine Intravenous heroin

Systemic disorders Portocaval encephalomyelopathy Inflammatory bowel disease Celiac disease Physical agents Electrical or lightning injuries Radiation Caisson disease (decompression sickness) System Degeneration Hereditary spastic paraplegia Spinal muscular atrophies Amyotropic lateral sclerosis (sporadic/familial) Inherited disorders Syringomyelia Chiari malformations Miscellaneous Myelopathy with corpora amylaceaâ € “ Polyglucosan body disease Spinal cord herniation

amyotrophic lateral sclerosis (motor neuron disease, Charcot's disease, Lou Gehrig's disease), in which degenerative changes occur in the anterior horn cells of the spinal cord (and in the motor nuclei of the brainstem) and in the corticospinal tracts. Progressive diffuse lower motor neuron signs (progressive muscular atrophy, paresis, and fasciculations) are superimposed on the signs and symptoms of upper motor neuron dysfunction (paresis, spasticity, and extensor plantar responses). Virtually any striated muscle may be affected, except the pelvic floor Bulbar or pseudobulbar impairment is often superimposed, resulting in explosive dysarthria, dysphagia, emotional incontinence, and tongue spasticity, atrophy, or weakness

Brown-Sequard Hemicord Syndrome This consists of ipsilateral weakness (corticospinal tract) and loss of joint position and vibratory sense (posterior column), with contralateral loss of pain and temperature sense (spinothalamic tract) one or two levels below the lesion. Segmental signs, such as radicular pain, muscle atrophy, or loss of a deep tendon reflex, are unilateral. Partial forms are more common than the fully developed syndrome.

Brown-Sequard Hemicord Syndrome This consists of ipsilateral weakness (corticospinal tract) and loss of joint position and vibratory sense (posterior column), with contralateral loss of pain and temperature sense (spinothalamic tract) one or two levels below the lesion. Segmental signs, such as radicular pain, muscle atrophy, or loss of a deep tendon reflex, are unilateral. Partial forms are more common than the fully developed syndrome.

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