Spinal Cord Disorders - Clinical Tree

Key Concepts

Nontraumatic spinal cord disorders can be intrinsic or extrinsic, some of which require prompt diagnosis, advanced imaging, and specialist intervention to prevent or limit permanent neurologic dysfunction.
The bulbocavernosus reflex is cord-mediated. Return of this reflex following a spinal injury marks the termination of spinal shock.
Anterior cord syndrome is marked by symmetrical motor loss but intact proprioception and vibration sense.
In patients with sudden severe back pain, consider spinal subarachnoid hemorrhage (SSAH) or spinal epidural hematoma (SEH), both of which are diagnosed using magnetic resonance imaging (MRI).
Transverse myelitis is inflammation of the spinal cord often associated with a prior viral infection resulting in paraplegia and a defined sensory level impairment. MRI with contrast enhancement is the diagnostic modality of choice. Roughly one-third of patients have a good outcome.
Cauda equina syndrome can be difficult to differentiate from conus medullaris lesions because both can result in bladder retention, fecal incontinence, leg weakness, and sensory loss in the perineum. Conus lesions are more typically bilateral, whereas cauda equina syndrome may be unilateral. Upper motor neuron findings are expected with conus lesions while cauda equina syndrome is associated with hypo- or areflexia.
Central cord syndrome is often due to a hyperextension injury. Physical findings are represented with the mnemonic MUD : M otor deficits > sensory, U pper extremities > lower, D istal extremity findings > proximal.
Brown-Séquard syndrome is due to a functional hemisection of the spine (frequently traumatic) resulting in ipsilateral loss of motor function, proprioception, and vibration with contralateral loss of pain and temperature sensation below the level of injury.
The diagnostic imaging of choice in the majority of suspected spinal disorders is MRI with contrast.
A syrinx is a cavitary lesion in the spinal cord that presents with a sensory disassociation predominately in the upper extremities. With progression, it can lead to upper extremity weakness and wasting. Symptom exacerbation with cough or Valsalva is typical.
With compressive lesions of the spinal cord, neurologic status at the time of intervention and the duration of symptoms are directly related to outcome.
Autonomic dysreflexia is a complication of spinal cord injury that can result in life-threatening hypertension. Hypertension may be the result of bladder distention, fecal impaction, pain, or infection. Treatment focuses on blood pressure management and the identification and treatment of inciting noxious stimuli.

Foundations

This chapter focuses on nontraumatic processes affecting the spinal cord, both extrinsic and internal. The ultimate neurologic outcome of patients with many of these disorders depends on expeditious recognition and management in the emergency department (ED).

Anatomy

In adults, the spinal cord is approximately 40 cm long and extends from the foramen magnum, where it is continuous with the medulla oblongata, to the body of the first or second lumbar vertebra (L1 to L2). The spinal cord is covered in the same three meningeal layers as the brain: the pia mater (innermost), arachnoid mater (middle), and dura mater (outermost). Inferiorly, the cord tapers into the conus medullaris (L1), where several segmental levels are represented in a small area. The lumbar and sacral nerve roots form the cauda equina as they descend caudally in the thecal sac before exiting the spinal canal at the respective foramina. The filum terminale, a non-neural strand of fibrous tissue composed of pia whose function is to suspend the cord in the subarachnoid space, runs from the tip of the conus and inserts into the dura at the level of the second sacral vertebra (S2).

Two symmetrical enlargements of the spinal cord contain the segments that innervate the limbs. The first occurs at the junction of the cervical (C) and thoracic (T) vertebrae. The cervical enlargement (C5 to T1) gives rise to the brachial plexus and peripheral nerves of the upper extremity. The second area is located at the junction of the thoracic and lumbar (L) vertebrae. The lumbar enlargement (L2 to S3) gives rise to the lumbosacral plexus and peripheral nerves of the lower extremity. The space surrounding the cord at these particular levels is reduced leaving it more vulnerable to external compression. At each segmental level, anterior (ventral) and posterior (dorsal) roots arise from rootlets along the anterolateral and posterolateral cord surfaces. Anterior roots convey the outflow of the motor neurons in the anterior horn of the spinal cord while posterior roots contain neurons and fibers that convey sensory inflow.

The arterial supply of the spinal cord is derived primarily from two sources ( Fig. 92.1 ). The single anterior spinal artery arises from the paired vertebral arteries at the base of the skull. It runs the entire length of the cord in the midline anterior median sulcus and supplies the anterior two-thirds of the spinal cord. Blood supply to the posterior third of the spinal cord is derived from the smaller paired posterior spinal arteries that arise from the vertebral arteries near the skull base and run bilaterally along the posterior cord. These three major spinal arteries receive segmental contributions from radicular arteries throughout their caudal projection, the largest being the artery of Adamkiewicz, which typically originates from the aorta between T8 and L4. The venous drainage of the cord largely parallels the arterial supply.

Fig. 92.1, Arterial blood supply to the spinal cord. The anterior spinal artery supplies blood to most of the anterior spinal cord, as well as the lateral column area of the cord ( darkly shaded area ). Some areas of the cord are supplied blood by both the anterior and posterior circulation ( light gray–shaded area ); there is variation among individuals. The anterior horn cells and lateral spinothalamic tracts rely on the anterior spinal artery for blood supply.

The internal anatomy of the spinal cord is divided into central gray matter, containing cell bodies and their processes, and surrounding white matter, where the ascending and descending myelinated fiber tracts are located. These white matter fiber tracts are organized into discrete bundles; the ascending tracts convey sensory information while the descending tracts convey the efferent motor impulses and visceral innervation.

For clinical purposes, neuroanatomy of the spinal cord may be greatly simplified, as depicted in Figure 92.2 . Tracts are named starting with the point of origin followed by the destination; the spinothalamic tract, for example, arises in the spinal cord and travels to the thalamus. Major ascending sensory tracts are labeled on the right side of the figure, with descending motor tracts on the left. The posterior column (dorsal column) carries afferent ascending proprioceptive and vibratory information on the ipsilateral side of the cord from the area stimulated to the brain; crossing of these fibers occurs in the medulla resulting in contralateral cortical representation. Within the cord, the posterior column is arranged with the sacral fibers existing medially and the cervical fibers laterally. The lateral spinothalamic tract conveys afferent information about pain and temperature in a portion of the lateral column of white matter. The tract is arranged so that sacral fibers are located laterally and cervical fibers medially, a reversal from the posterior column arrangement. Crossing of fibers from this tract occurs near the level of entry of the spinal nerve resulting in contralateral representation in the cord. This is why an isolated cord lesion affecting a spinothalamic tract results in decreased or absent pain and temperature perception below the level of injury on the opposite side of the body.

Fig. 92.2, Simplified spinal cord anatomy showing clinically essential motor and sensory tracts.

The major descending motor tract is represented in the lateral corticospinal tract, originating in the cortex of the brain and traveling to the spinal cord. Crossing of this tract occurs in the medulla, similar to the ascending posterior column, meaning that motor signals from one side of the brain ultimately descend down the opposite cord side and result in motion of the contralateral body. This tract is organized similar to the lateral spinothalamic, with sacral fibers located laterally and the cervical fibers medially. The cell bodies of the lower motor neurons (anterior horn cells) are in the ventral portion of the gray matter of the spinal cord.

Classification of Spinal Cord Syndromes

The anatomic organization of the spinal cord lends itself to a corresponding anatomic-pathophysiologic classification of cord dysfunction ( Table 92.1 ). Any of the different cord syndromes may be the final clinical picture of a variety of pathologic processes. These syndromes do frequently exist in partial or incomplete forms, adding to the diagnostic challenge.

TABLE 92.1

Spinal Cord Syndromes

Syndrome	Sensory	Motor	Sphincter Involvement
Central cord syndrome	Variable	Upper extremity weakness, distal > proximal	Variable
Brown-Séquard syndrome	Ipsilateral position and vibration sense loss Contralateral pain and temperature sensation loss	Motor loss ipsilateral to cord lesion	Variable
Anterior cord syndrome	Loss of pain and touch sensation Vibration, position sense preserved	Motor loss or weakness below cord level	Variable
Transverse (complete) cord syndrome	Loss of sensation below level of cord injury	Loss of voluntary motor function below cord level	Sphincter control lost
Conus medullaris syndrome	Saddle anesthesia may be present; Sensory loss may range from patchy to complete transverse pattern	Weakness may be of upper motor neuron type; Bilateral	Sphincter control impaired
Cauda equina syndrome	Saddle anesthesia may be present; Sensory loss may range from patchy to complete transverse pattern	Weakness may be of lower motor neuron type; Unilateral	Sphincter control impaired

Complete (Transverse) Spinal Cord Syndrome

Complete spinal cord lesions may be manifested as either acute or subacute processes. It is defined as a total loss of sensory, autonomic, and voluntary motor innervation distal to the spinal cord level of injury. Neural responses mediated at the spinal level, such as deep tendon reflexes, may persist but may also be absent (early stages) or hyperreflexic (later stages). Autonomic dysfunction may be manifested acutely with hypotension (neurogenic shock) or priapism. The most common cause of a complete cord syndrome is trauma, though other etiologies are possible including infarction, hemorrhage, and extrinsic compression. In patients with complete syndromes that persist for more than 24 hours, functional recovery almost never occurs. Any evidence of preserved cord function below the level of injury denotes a partial rather than complete lesion. Signs such as persistent perineal sensation (sacral sparing), reflex rectal sphincter tone or voluntary rectal sphincter contraction, and even slight voluntary toe movement suggest a partial cord lesion, which carries a better prognosis than a complete lesion.

Spinal shock refers to the loss of muscle tone and reflexes with a complete cord syndrome during the acute phase of injury. It typically lasts less than 24 hours but has been reported to occasionally last days or weeks. A marker of spinal shock is loss of the bulbocavernosus reflex, which is a normal cord-mediated reflex that may be preserved in complete cord lesions. The bulbocavernosus reflex involves involuntary contraction of the anal sphincter in response to a squeeze of the glans penis, clitoris, or outward tug on a Foley catheter. Termination of the spinal shock phase of injury is heralded by the return of the bulbocavernosus reflex, with increased muscle tone and hyperreflexia following later.

Incomplete (Partial) Spinal Cord Lesions

Incomplete lesions are characterized by functional preservation of various portions of the spinal cord. Of the many possible incomplete lesions, most can be classified as one of three clinical syndromes based on functionality: (1) central cord syndrome, (2) Brown-Séquard syndrome, or (3) anterior cord syndrome.

Central Cord Syndrome

Central cord syndrome is the most common of the partial cord syndromes. Because of the anatomic organization of the spinal cord, a central cord injury is characterized by bilateral motor paresis. The upper extremities and distal muscle groups are affected to a greater degree than the lower extremities and proximal muscle groups. Sensory impairment and bladder dysfunction are variable features. At times, burning dysesthesias in the upper extremities may be the dominant clinical feature. The mnemonic “MUD” can aid in recall of these features: M otor greater than sensory, U pper greater than lower, D istal greater than proximal.

Central cord syndrome affects the central gray matter and the central portions of the corticospinal and spinothalamic tracts. It is most often caused by a hyperextension injury, frequently from falls or motor vehicle accidents. The postulated mechanism is squeezing of the cord anteriorly and posteriorly due to inward bulging of the dorsally located ligamentum flavum resulting in a contusion to the spinal cord which most affects the central cord. This injury often occurs in elders with degenerative arthritis and spinal stenosis in the cervical area but can affect patients with cervical canal narrowing of any etiology (i.e., disc protrusion, tumor, or congenital narrowing as in achondroplasia). The prognosis depends on the degree of injury at presentation as well as the patient’s age, with advanced age predicting decreased functional outcome. In patients younger than 50 years old, more than 80% regain bladder continence and approximately 90% return to full ambulatory status; in patients older than 50 years, only 30% regain bladder function and approximately 50% regain the ability to ambulate.

Brown-Séquard Syndrome

Brown-Séquard syndrome is the result of an anatomic or functional hemisection of the spinal cord. Usually associated with penetrating injuries, Brown-Séquard syndrome also may be seen with compressive or intrinsic lesions. It has been reported in association with spinal cord tumors, spinal epidural hematomas, vascular malformations, cervical spondylosis, degenerative disc disease, herpes zoster myelitis, radiation injury, and as a complication of spinal instrumentation. In its pure form, it is characterized by ipsilateral loss of motor function, proprioception, and vibration sense with contralateral loss of pain and temperature sensation below the level of injury. Because fibers associated with the lateral spinothalamic tract ascend one or two spinal cord segments before crossing to the contralateral side, ipsilateral anesthesia (pain and temperature modalities) may be noted one or two segments above the lesion, although this observation is variable. Most patients with this syndrome incur only partial sensory and motor impairment, so the classic pattern is not always seen. Brown-Séquard syndrome carries the best prognosis of any of the incomplete spinal cord syndromes. Fully 80% to 90% of patients regain bowel and bladder function, 75% regain ambulatory status, and 70% become independent in their activities of daily living.

Anterior Cord Syndrome

Anterior cord syndrome is characterized by loss of motor function, pinprick, and light touch below the level of the lesion with preservation of the posterior column modalities, including position, vibration, and some touch. Although most reported cases of anterior spinal cord syndrome follow aortic surgery, it may also occur after severe hypotension, infection, myocardial infarction, vasospasm from drug reaction, and aortic angiography. Mechanically, the lesion may be caused by cervical hyperflexion resulting in a cord contusion or by protrusion of bone fragments or herniated cervical disc material into the canal. Rarely, it is produced by laceration or thrombosis of the anterior spinal artery or a major radicular vessel. Functional recovery varies, with most improvement occurring during the first 24 hours and little improvement thereafter. Although anterior cord lesions from ischemia usually are incomplete, patients without motor function at 30 days have little or no likelihood of regaining any motor function by 1 year. Only 10% to 20% of patients regain some muscle function, and even in this group there is little power or coordination.

Conus Medullaris and Cauda Equina Syndromes

The differentiation between conus medullaris and cauda equina lesions in clinical practice is difficult because the two disorders overlap in their clinical presentation. In addition, a combined lesion can mask clear clinical symptoms or signs of either an upper or a lower motor neuron type of injury.

Physical features of conus medullaris syndrome may involve disturbances of urination (usually from a denervated, spastic, autonomic bladder that manifests as overflow incontinence) and sphincter impairment (decreased rectal tone) or erectile dysfunction. Sensory involvement may affect the sacral and coccygeal segments, resulting in saddle anesthesia. Pure lesions of the conus medullaris are rare. Upper motor neuron signs, such as increased motor tone and hyperreflexia, may be present, but their absence does not exclude the syndrome.

Conus medullaris syndrome can be caused by central disc herniation, neoplasm, trauma, or vascular insufficiency. Because the conus is such a small structure, with lumbar and sacral segments represented in a minimal area, a lesion will usually cause bilateral symptoms. This finding may help distinguish conus medullaris lesions from those in the cauda equina, which often are unilateral.

Cauda equina (Latin for “horse’s tail”) is the name given to the lumbar and sacral nerve roots that continue on within the dural sac distal to the conus medullaris. Not a true “cord syndrome” as the cord itself is unaffected, cauda equina syndrome represents dysfunction at the level of nerve roots. The anatomic clustering of nerve roots within the lumbar dural sac allows insult to multiple nerve roots to occur simultaneously.

Cauda equina syndrome is usually caused by the midline rupture of an intervertebral disc most commonly at the L4 to L5 level, but any compressive mass can cause it. As in conus medullaris syndrome, patients generally present with progressive symptoms of fecal or urinary incontinence, impotence, decreased rectal tone, distal motor weakness, and saddle anesthesia. Deep tendon reflexes may be reduced. All of these findings have low sensitivity but moderately good specificity in the diagnosis, with saddle anesthesia and bowel/bladder changes having a specificity range of 70% to 89%. Of note, a complaint of low back pain may or may not be present.

Clinical Features

History

Weakness, sensory abnormalities, and autonomic dysfunction are the cardinal manifestations of spinal cord dysfunction. The tempo and degree of impairment often reflect the disease process. Past medical history is vital because an underlying coagulopathy or other systemic process may be elicited. A history of cancer suggests the possibility of metastatic disease. Recent trauma raises the possibility of vertebral fracture or disc protrusion. The acuity of pain can help narrow the differential diagnosis as well, with sudden pain or dysfunction more likely to be a vascular catastrophe, and slower onset, midline pain in the setting of fever points toward an infectious source.

Physical Examination

The physical examination pertinent to spinal cord dysfunction involves testing in three areas: (1) motor function, (2) sensory function, and (3) reflexes. Each component is best tested with the anatomic organization of the spinal cord in mind to help determine the level of dysfunction. A detailed description of neurologic deficits and their correlating spinal level can be found in Chapter 35 .

Motor Function

Testing of motor function encompasses examination of muscle bulk, tone, and strength. Muscle bulk is easily examined in large motor groups, such as the thigh, the calf, or the upper arm. Inspection of intrinsic hand muscles may also be helpful in determination of bulk; wasting may be evident as hollowed or recessed regions of the hand. Any decreased mass, asymmetry, or fasciculations should be noted. Tone is tested with repeated passive knee, elbow, or wrist flexion, or by rapid passive forearm pronation-supination, with the examiner assessing for abnormally increased or decreased resistance. Increased tone may indicate spasticity or an upper motor neuron lesion whereas decreased tone corresponds with lower motor neuron, motor end-plate, or muscle problems. Motor strength is then graded in the upper and the lower extremities. Motor grading for the neurologic examination is relatively straightforward; scored on a scale of 0 to 5, as shown in Table 92.2 .

TABLE 92.2

Grading of Neuromuscular Weakness

Grade	Physical Findings
0	No firing of the muscle is present.
1	The muscle fires but is unable to move the intended part.
2	The muscle is able to move the intended part with gravity eliminated.
3	The muscle is able to move the intended part against gravity.
4	The muscle is able to move the intended part but not at full strength.
5	Full muscle strength is present.

A rectal examination and the bulbocavernosus reflex (involuntary anal sphincter contraction in response to a squeeze of the glans penis or clitoris or a tugging on a Foley catheter) are performed to assess voluntary sphincter contraction and resting tone. Although not commonly thought of as a physical examination maneuver, a post-void residual (PVR) urine volume is useful to evaluate bladder function. A PVR of more than 100 to 200 mL in a patient without prior voiding difficulty suggests bladder dysfunction of a neurologic cause.

Sensory Function

Sensory testing requires a cooperative patient and an attentive examiner. Assessment of the patient’s response to pinprick and light touch (contralateral spinothalamic tract) and proprioception (ipsilateral posterior column) in all four extremities is necessary. Testing of sacral dermatomes is indicated, as sparing suggests that a lesion may be incomplete. The sensory fibers from these dermatomes are more peripherally located in the ascending fiber bundles, thus, central or partial cord lesions may ablate sensation in the extremities yet allow some perception in the sacral area.

Reflexes

Deep tendon (muscle stretch) reflexes are graded on a scale of 0 to 4+, with 2 being normal. Hyperactive reflexes suggest upper motor neuron disease (affecting the neurons or their outflow from the brain or spinal cord) as do sustained clonus and Babinski sign. If present, hyperactive or abnormally brisk reflexes may be a key finding suggesting a myelopathy. However, absence of hyperreflexia does not exclude one. Reflexes may be diminished or absent when sensation is lost, when spinal shock is present, or in diseases of muscles or the neuromuscular junction. In acute cord injury, reflexes can be diminished in the acute phase, therefore, the bulbocavernosus reflex may be helpful in this assessment.

Differential Diagnoses

The prime principle in management of spinal cord dysfunction is to consider and diagnose potentially treatable and time-sensitive conditions. The clinician should rule out any nonstructural cause of neurologic dysfunction (e.g., hypoglycemia, hypokalemia) early in the evaluation process. Once a true neurologic entity is suspected, the next step is to differentiate the location of the lesion (i.e., brain, spinal cord, nerve or motor end-plate). When the pathologic process is suspected to be spinal in origin, liberal use of specialist consultation and imaging is generally warranted. Spinal cord disorders may mimic many other disease processes, and neither the history nor physical examination can reliably enable a true diagnosis until appreciable neurologic dysfunction has developed.

The picture of a complete (transverse) spinal cord syndrome with paraplegia, sensory loss at a clear anatomic level, and sphincter dysfunction cannot be fully mimicked by other anatomic lesions; incomplete or evolving spinal cord syndromes, however, can. Ataxia, for example, is often a finding in cerebellar disease but has been reported as a rare, isolated finding in spinal cord compression.

In general, pathologic processes involving the spinal cord may be divided into those affecting the cord or its blood supply (e.g., demyelination, infection, or infarction) and ones that compress the cord. Of note, myelitis is a comprehensive term for spinal cord inflammation with dysfunction. The clinical presentation is often similar across the many etiologies of cord compression, but the tempo of the process may yield a different clinical picture. In chronic compression, muscle wasting and abnormal reflexes may be present, whereas both of these findings are likely to be lacking in acute compression.

Diagnostic Testing

The purpose of diagnostic testing in patients suspected of having spinal cord dysfunction is to detect or exclude extrinsic compressive lesions or other potentially treatable entities. Conventional radiographs and computed tomography (CT) scans are essential in patients with trauma or suspected bony involvement by tumor or degenerative process because they better define bone and can show some soft tissue abnormalities. However, due to its ability to clearly define the spinal cord and the soft tissue structures around it, magnetic resonance imaging (MRI) is the preferred modality in assessing spinal cord disorders. It may also detect tissue damage patterns within the cord, such as hemorrhage and edema, as well as bone pathology. When utilized, MRI assessment of the entire spine should be considered because lesions can frequently occur at multiple levels.

MRI with gadolinium contrast enhancement is indicated when looking for pathology that affects the blood–central nervous system (CNS) barrier. Specific indications include primary or metastatic tumor, multiple sclerosis (MS), and spinal infections (i.e., spinal epidural abscess, discitis, and osteomyelitis). An example of the utility of gadolinium enhancement is seen in Figure 92.3 . CT myelography is an option when MRI is unavailable or contraindicated, although it does not yield the same level of detail.

Fig. 92.3, 90-year-old female with recent pyelonephritis presenting with severe neck pain. Pregadolinium sequence (A) compared with postgadolinium sequence (B) demonstrates posterior spinal epidural abscess (SEA) (yellow arrowheads).

After imaging studies exclude compressive lesions or other masses affecting the spinal cord, the possibility of inflammatory or demyelinating disorders remains. In these cases, lumbar puncture with cerebrospinal fluid (CSF) analysis may be diagnostic.

Management

The treatment of many of the disease processes causing spinal cord dysfunction is nonspecific and based on limited evidence. Steroids have been used with many nontraumatic causes of cord compression, particularly spinal cord tumors, despite the lack of rigorous clinical studies supporting this practice. Radiation treatment is recommended for cord compression by tumor; surgical consultation for decompression may be considered, although the indications and timing for surgery are controversial.

Specific Disease Processes

Spinal cord disorders are grouped into lesions resulting from processes intrinsic to the cord or vasculature and lesions causing extrinsic compression ( Table 92.3 ).

TABLE 92.3

Causes and Characteristics of Nontraumatic Spinal Cord Dysfunction

Disease Process	Symptoms/Examination Findings	Testing	Treatment
Intrinsic Lesions
Multiple Sclerosis	Symptoms include sensory, visual (optic neuritis), GI, fatigue, weakness, labile mood, hyperreflexia.	MRI, LP, consider biopsy	Steroids + disease-modifying medications
Transverse Myelitis	Paraplegia, transverse sensory impairment, and sphincter disturbance.	MRI	±Glucocorticoid therapy (etiology dependent)
Spinal Subarachnoid Hemorrhage	Usually have focal deficits on examination at level of bleed. May also complain of headache and/or demonstrate nuchal rigidity on exam.	MRI +/− LP	Anticoagulation reversal +/− clot evacuation
Syringomyelia	Headache with neck pain and sensory disturbances. Frequently demonstrate lower limb hyperreflexia with hand weakness and dissociative anesthesia.	MRI	Neurosurgical consultation vs. outpatient follow-up
HIV Myelopathy	Advanced HIV infection with weakness, gait disturbance, and sensory abnormalities.	Diagnosis of exclusion	Supportive therapy, HAART
Spinal Cord Infarction	Findings depend on location of infarction but anterior cord syndrome is most common.	Diagnosis of exclusion	Dependent on etiology
Surfer’s Myelopathy	Back pain, paresis, and urinary retention.	MRI	Conservative therapy
Extrinsic Lesions
Spinal Epidural Hematoma	Sudden severe radicular back pain usually presents prior to onset of deficits. Exam findings depend on location of hematoma.	MRI	Decompressive laminectomy
Spinal Epidural Abscess	Classically febrile with progressive neurological deficits. Back pain may be worse with percussion.	MRI	IV antibiotics ± surgery vs. needle decompression
Discitis	Children with back pain at level of lesion. Subacute presentation with fever but no neurologic deficits.	MRI	IV antibiotics
Neoplasm	Nighttime pain worse with lying flat. Deficits depend on location of lesion.	CT or MRI	Glucocorticoid therapy + radiation therapy or surgery

Intrinsic Cord Lesions

Multiple Sclerosis

Demyelination denotes a disease process with the prominent feature of partial or complete loss of the myelin surrounding the axons of the CNS. Multiple sclerosis (MS) is the most common example of such a process. The spinal cord is involved in as many as 90% of MS patients. In approximately 20% of patients, the spinal cord lesions will be the only area where plaques are identified. The pathophysiology, diagnosis, and management of MS is discussed in Chapter 94 .

Transverse Myelitis

Foundations

Acute transverse myelitis (TM) refers to acute or subacute spinal cord dysfunction characterized by paraplegia, a transverse level of sensory impairment, and sphincter disturbance. It is often considered part of a heterogeneous group of inflammatory processes known as neuromyelitis opticum spectrum disorders (NMOSD). TM affects the spinal cord by interrupting the ascending or descending pathways. The presentation may be mimicked by compressive lesions, trauma, infection, or malignant infiltration.

The pathogenesis of transverse myelitis is unknown, although it is noted to follow a viral infection in approximately 30% of patients and therefore often termed postinfectious myelitis. Other postulated etiologies include infectious, autoimmune, and idiopathic disorders. It can be seen with a wide variety of connective tissue diseases, such as lupus, Sjögren syndrome, antiphospholipid syndrome, and other mixed connective tissue diseases. More recent research points to the presence of anti-AQP4 antibodies, particularly in cases thought to be part of NMOSD. No cause is identified in 30% of patients. Progression of symptoms is usually rapid, with 66% of the cases reaching maximal deficit by 24 hours. However, symptoms may progress over days to weeks. The thoracic cord region is affected in 60% to 70% of cases, with the cervical cord being rarely involved. When TM lesions span 3 or more spinal cord levels, it is termed longitudinally extensive transverse myelitis (LETM) and is considered a hallmark of NMOSD.

Clinical Features

In addition to motor, sensory, and urinary disturbances, patients with acute transverse myelitis may complain of back pain as well as a low-grade fever, raising concern for SEA. As with MS, the examination may reveal weakness progressing to paresis, hypertonia, hyperreflexia, clonus, Babinski response, and anal sphincter dysfunction. A distinct sensory level deficit is usually present. Autonomic dysfunction may also be noted as hyper- or hypotension and tachy- or bradycardia.

Differential Diagnoses

Considerations in the differential diagnosis for transverse myelitis include MS, SEA, spinal epidural hematoma (SEH), primary or metastatic spinal neoplasm, spinal cord infarct, surfer’s myelopathy, and vitamin B ₄ deficiency.

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