5 Nonoperative Neurological Diseases of the Thoracic Spinal Cord

A thoracic cord lesion typically presents with pain and numbness in a band-like distribution around the chest or abdomen radiating inferiorly. Muscle weakness may not be clear initially in the thoracic region due to significant overlap in the intercostal musculature. However, if the lesion involves the ascending corticospinal tracts, upper motor neuron motor deficits may affect the lower extremities causing weakness, increased tone, and hyperreflexia. Back pain and exertional leg pain are common. A spastic gait or even inability to walk may be present. If the lesion is above T6, autonomic dysfunction may occur causing cardiopulmonary, bowel, bladder, and sexual dysfunction. Patients with chronic myelopathies are at higher risk for coronary artery disease, pneumonia, deep venous thrombosis, pulmonary embolism, urinary tract infections, pressure ulcers, contractures, osteoporosis, and chronic constipation.¹

5.3 Inflammatory Myelopathies

Inflammation of the spinal cord, known as transverse myelitis (whether involving the whole cord or only involving part of the cord), can be caused by many different disease entities or may be idiopathic. Inflammatory myelitis may occur over hours to weeks though generally reaches its peak severity in under a month if untreated.² Weakness in the early phase may be associated with flaccid tone and hyporeflexia; the typical upper motor neuron signs of myelopathy may occur later, and this can prove to be diagnostically challenging. Signs of inflammation can be seen on magnetic resonance imaging (MRI) with gadolinium contrast enhancement in the spinal cord and with cerebrospinal fluid (CSF) patterns of pleocytosis, elevated protein, oligoclonal bands, or elevated immunoglobulin G (IgG) index ( Fig. 5.1). In almost all cases of transverse myelitis, first-line treatment is high-dose intravenous (IV) methylprednisolone (1 g daily for 3–7 days) even if the cause of the inflammation is unknown. Despite the lack of studies to support this, steroids are generally used to quicken recovery and restore neurological function.³ In general, among all cases of transverse myelitis, the prognosis is split into thirds with one-third recovering with minimal or no sequelae, one-third with moderate disability, and one-third with severe disability.⁴

5.3.1 Multiple Sclerosis

Multiple sclerosis is the most common immune-mediated inflammatory disease of the central nervous system affecting the myelin of axons within the brain, optic nerves, and spinal cord. Transverse myelitis due to multiple sclerosis commonly involves short segments of the spinal cord (spanning less than three vertebrae) and is often located dorsally² ( Fig. 5.2). Inflammation of the spinal cord tends to be partial, showing asymmetric neurological signs.⁵ Involvement of the spinal cord is known to be correlated with disability outcomes.⁶ Though cervical cord lesions have been more frequently studied in clinical trials of multiple sclerosis, there is growing evidence to suggest that thoracic cord lesions may be more common than previously thought, and diagnosing thoracic lesions may be important in clinical management and prognosticating on future disability.^6,7 Though the vast majority of people with acute transverse myelitis secondary to multiple sclerosis improve, only about half show complete recovery.⁵ Risk factors for acute transverse myelitis as an initial event progressing into multiple sclerosis include family history of multiple sclerosis, severe impairment at onset, brain MRI lesions typical of multiple sclerosis, abnormal IgG index in the CSF, and the presence of CSF oligoclonal bands.⁵ Acute treatment of transverse myelitis due to multiple sclerosis consists of IV steroids and less often plasma exchange. There are many disease-modifying treatments currently available for multiple sclerosis including injectable, oral, and IV medications that reduce the number of new lesions and number of relapses over the course of the disease.

Fig. 5.1 (a) Sagittal and (b) axial images of a 51-year-old man with transverse myelitis involving the thoracic spinal cord (arrows) that has high signal involving more than two-thirds of the cross-sectional area of the spinal cord. (c) Axial fat-suppressed T1-weighted imaging shows gadolinium contrast enhancement of the actively demyelinating lesion (arrow). (Reproduced from Meyers SP. Differential Diagnosis in Neuroimaging: Spine. New York, NY: Thieme; 2017: 73.)

Neuromyelitis optica (NMO), another demyelinating disorder, used to be considered a variant of multiple sclerosis but is now seen as a distinctly separate disease.⁸ Similar to multiple sclerosis, NMO can affect many different parts of the central nervous system, though there is a predilection for the spinal cord and optic nerves. Presence of an autoantibody biomarker against aquaporin-4 water channels is considered sufficient to make a diagnosis of NMO, though there are also NMO spectrum disorders that are aquaporin-4 seronegative.⁸ Cord lesions tend to be more extensive than those seen in multiple sclerosis, often spanning more than three vertebral segments ( Fig. 5.3). Clinical attacks are often more severe and disabling than multiple sclerosis, and plasma exchange in addition to steroids may be necessary for better outcomes. Maintenance therapy usually consists of immunosuppressants such as rituximab, azathioprine, or mycophenolate mofetil, though data supporting their use are limited.^2,8

5.3.3 Neurosarcoidosis

Sarcoidosis is a granulomatous disease commonly affecting the lung or lymph nodes that may also rarely (about 5%) affect the spinal cord, cranial nerves, and brain. It is often difficult to distinguish from multiple sclerosis or NMO, though the course may be more subacute, and MRI may more often show leptomeningeal enhancement ( Fig. 5.4).⁴ Chest imaging to look for pulmonary involvement helps to aid in the diagnosis. Serum and CSF angiotensin-converting enzyme levels may also help with the diagnosis, though sensitivity tends to be poor. Acute therapy consists of steroids and antitumor necrosis factor therapy for refractory cases.²

5.3.4 Connective Tissue Disorders

Several connective tissue disorders can cause transverse myelitis, including systemic lupus erythematosus (SLE), Sjögren’s syndrome, mixed connective tissue disorder, and systemic scleroderma.

SLE is a chronic and relapsing–remitting autoimmune disorder that may affect multiple organ systems including joints, skin, kidneys, lungs, and heart. Neuropsychiatric involvement is seen in as many as 60% of cases and may present as seizures, stroke, or psychosis, though transverse myelitis is only seen in about 1 to 2% of people with SLE.⁹ Several autoantibodies are associated with SLE including antinuclear antibody and double-stranded DNA antibody, though particularly associated with SLE myelitis is the antiphospholipid antibody.⁴ Treatment with IV steroids and occasionally with cyclophosphamide and plasma exchange is generally effective, with complete recovery occurring in about 50% of patients, partial improvement in close to 30%, and no improvement or worsening seen in about 20%.⁹

Fig. 5.2 Multiple sclerosis in a 22-year-old woman with a 6-week history of sensory disturbances in her right arm. No other symptoms were present. CSF was positive for oligoclonal bands. (a) Axial FLAIR sequence of the brain demonstrates multiple hyperintense lesions. (b) Axial DIR sequence of the brain. The lesions are depicted in higher contrast. (c) Sagittal T2-weighted image of the cervical spine demonstrates multiple hyperintense lesions. Each of the lesions spans no more than one vertebral body height. (d) Sagittal T1-weighted sequence after contrast administration. Individual lesions show marked enhancement. (Reproduced from Schlamann M. Inflammations, infections, and related diseases. In: Forsting M, Jansen O, eds. MR Neuroimaging: Brain, Spine, Peripheral Nerves. New York, NY: Thieme; 2017:519.)

Fig. 5.3 Neuromyelitis optica in a 25-year-old woman with left-sided optic neuritis and quadriparesis. CSF examination showed pleocytosis. Serum test was positive for aquaporin antibodies. (a) FLAIR image of the brain shows a small, nonspecific white-matter hyperintensity in the left frontal region. (b) Sagittal T2-weighted image of the cervical spine shows hyperintensity extending along the spinal cord from the C1-5 levels. (c) Axial T1-weighted image after contrast administration shows circumscribed enhancement on the right side. (d) Sagittal T1-weighted image after contrast administration. The T2-weighted hyperintensity in panel (b) shows partial enhancement. (Reproduced from Schlamann M. Inflammations, infections, and related diseases. In: Forsting M, Jansen O, eds. MR Neuroimaging: Brain, Spine, Peripheral Nerves. New York, NY: Thieme; 2017:522.)

Sjögren’s syndrome, another chronic multisystem autoimmune disorder, typically causes sicca symptoms including dry eyes, dry mouth, and parotid gland enlargement. Anti-Sjögren’s-syndrome–related antigen A (SSA/Ro) and anti-Sjögren’s-syndrome–related antigen B (SSB/La) antibodies are commonly associated with this disorder. Neurological symptoms occur in about 20% of patients with Sjögren’s syndrome, most commonly affecting the sensory ganglions, small fiber nerves, and spinal cord.¹⁰ Spinal cord lesions, like NMO, tend to be longitudinally extensive ( Fig. 5.5). Similar to SLE, IV steroids are the mainstay of treatment with cyclophosphamide often used for refractory cases.

Fig. 5.4 Sarcoidosis in a 56-year-old woman with tingling paresthesias in the lower limb and a sensory level caudal to T9. She was known to have sarcoidosis. CSF examination showed lymphocytic pleocytosis with 170 cells/μL and positive oligoclonal bands. (a) Sagittal T1-weighted image with contrast shows a fine nodular, almost miliary pattern of intramedullary enhancement that is most pronounced in the thoracic spine. (b) Sagittal T2-weighted image of the spine. Some of the larger granulomas appear hyperintense in the T2-weighted sequence. (c) Axial T1-weighted image with contrast at the level of the C4 vertebral body shows circumscribed enhancement of a granuloma. (d) Fat-saturated sagittal T1-weighted image with contrast in a different patient with known neurosarcoidosis shows typical peripheral meningeal enhancement of the spinal cord. Image quality is compromised due to poor compliance. (Reproduced from Schlamann M. Inflammations, infections, and related diseases. In: Forsting M, Jansen O, eds. MR Neuroimaging: Brain, Spine, Peripheral Nerves. New York, NY: Thieme; 2017:529.)

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