Acute Spinal Cord Syndromes



Acute Spinal Cord Syndromes


Natalie R. Weathered

Noam Y. Harel



INTRODUCTION

Patients presenting with acute spinal cord syndromes represent true neurologic emergencies. Pathologic damage to the cord is usually incomplete. Therefore, there is opportunity to salvage (and peril of losing) vital cord tissue and function over the ensuing minutes and hours after presentation. As with other neurologic presentations, clinicians must first localize and then differentiate the type of damage in order to initiate the most effective interventions.




SPINAL CORD ANATOMY

To aid with localization, recall that the caudal spinal cord segments do not align with the vertebrae bearing the same names. The spinal cord ends around L1, with the roots of the cauda equina below that vertebral level. Additionally, within the cervical cord, the spinal roots exit the spinal canal above the associated vertebral level except for root C8, which exits between C7 and T1. Thereafter, each spinal root exits below the corresponding vertebral body.


MOTOR SYSTEM

The majority of the corticospinal tract, mediating a large proportion of our volitional limb movements, decussates in the medulla before descending in the contralateral lateral corticospinal tract. The minority of motor axons that do not decussate within the medulla form the anterior corticospinal tract. The lower motor neurons, receiving input from corticospinal fibers as well as segmental interneurons, reside within the ventral horn (Fig. 16.1).


SENSORY SYSTEM

Afferent sensory fibers from the dorsal root ganglia enter the spinal cord at the dorsal horn. From there, their course depends on the type of modality being transmitted.


Pain and Temperature

These fibers travel rostrally within Lissauer tract for one or two spinal segments before synapsing within the dorsal horn and crossing to the contralateral anterolateral system. The anterolateral system is composed of the anterior spinothalamic tract, which carries crude touch sensory fibers, and the lateral spinothalamic tract, which carries pain and temperature fibers.








TABLE 16.1 Differential Diagnosis for Acute Spinal Syndromes
















































































































































































































Compressive/mechanical



Trauma



Disk herniation



Epidural abscess



Epidural hematoma



Epidural neoplasm/metastasis



Vertebral compression fracture


Vascular



Ischemic stroke



Dural arteriovenous fistula



Arteriovenous malformation



Cavernous malformation


Inflammatory



Multiple sclerosis



Neuromyelitis optica



Transverse myelitis



Acute disseminated encephalomyelitis (ADEM)



Sarcoidosis



Paraneoplastic



Systemic lupus erythematosus (SLE)



Antiphospholipid antibody syndrome (APS)



Sjögren syndrome



Mixed connective tissue disease (MCTD)



Behçet disease


Toxic/metabolic



Heroin



Konzo



Arachnoiditis after angiographic/myelographic contrast agents



Methotrexate toxicity



Cytarabine toxicity



Amphotericin B toxicity


Neoplasm


Infectious



Viral gray matter/acute flaccid paralysis




Poliovirus




Enterovirus




Coxsackieviruses A & B




West Nile virus (WNV)




Japanese encephalitis (JE)




Tick-borne encephalitis



Viral white matter/longitudinal myelitis




Herpes simplex virus (HSV)




Varicella-zoster virus (VZV)




Cytomegalovirus (CMV)




Epstein-Barr virus (EBV)




Influenza



Bacterial




Mycoplasma pneumoniae




Syphilis




Tuberculosis




Lyme



Fungal




Cryptococcus neoformans




Coccidioides immitis




Blastomycetes dermatitides




Histoplasma capsulatum




Candida species




Aspergillus species




Zygomycetes



Parasitic



Schistosoma species



Toxoplasma gondii



Taenia solium (cysticercosis)










TABLE 16.2 Classic Spinal Cord Syndromes

































Syndrome


Typical Causes


Clinical Characteristics


Central cord syndrome (syringomyelia)


Underlying cervical spondylosis with hyperextension injury; damage relatively greater to gray than white matter


Weakness in upper extremities > in lower extremities; may have neurogenic bladder dysfunction and varying degrees of sensory loss at or below the lesion (often in a “cape-like” distribution).


Brown-Séquard syndrome


Penetrating trauma (many nonpenetrating injuries show partial asymmetric syndromes)


Ipsilateral motor and vibration/proprioception loss below the lesion, contralateral pain/temperature loss two levels below the lesion


Anterior cord syndrome


Hypotensive event leading to infarct within the midthoracic region, or hyperflexion injury leading to compression of the anterior spinal artery


Bilateral loss of motor, pain/temperature sensation below the lesion with preservation of vibration/proprioception/two-point discrimination


Posterior cord syndrome


B12 deficiency, MS, vascular malformations, atlantoaxial subluxation


Bilateral loss of vibration/proprioception/two-point discrimination with preservation of motor, pain/temperature sensation below the lesion


Cauda equina syndrome


Disk herniation, tumor


Asymmetric lower extremity weakness, patchy impaired sensation to all modalities, loss of deep tendon reflexes as well as bulbocavernosus reflex and anal wink, often with low back and radicular pain


Conus medullaris syndrome


Disk herniation, trauma, tumor


Symmetric sacral > lumbar weakness (may have normal leg strength), saddle anesthesia, bowel/bladder dysfunction


MS, multiple sclerosis.



Vibration, Proprioception, and Two-Point Discrimination

These fibers travel within the ipsilateral dorsal columns to the gracilis and cuneatus nuclei of the lower medulla. Axons from the legs (fasciculus gracilis) are pushed medially by entering axons from the arms (fasciculus cuneatus) (see Fig. 16.1).


AUTONOMIC SYSTEM


Sympathetic

Sympathetic preganglionic neurons are located within the inter-mediolateral nucleus of the thoracic and upper lumbar (L1-L2) spinal cord. Their axons exit via the ventral roots and synapse on the postganglionic sympathetic neurons in the paravertebral ganglia (the “sympathetic chain ganglia”) or the prevertebral ganglia.






FIGURE 16.1 Anatomy of the spinal cord (cross-section). Tract lamination: S, sacral segments; L, lumbar segments; Th, thoracic segments; C, cervical segments. (From Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 5th ed. Philadelphia: Lippincott Williams and Wilkins; 2007.)

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Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on Acute Spinal Cord Syndromes
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