Spinal Cord Infarction
Spinal cord infarction usually results from ischemia originating in an extravertebral artery. Symptoms include sudden and severe back pain, followed immediately by rapidly progressive bilateral flaccid limb weakness and loss of sensation, particularly for pain and temperature. Diagnosis is by MRI. Treatment is generally supportive.
(See also Overview of Spinal Cord Disorders.)
The primary vascular supply for the posterior third of the spinal cord is the posterior spinal arteries; for the anterior two thirds, it is the anterior spinal artery. The anterior spinal artery has only a few feeder arteries in the upper cervical region and one large feeder (the artery of Adamkiewicz) in the lower thoracic region. The feeder arteries originate in the aorta.
Because collateral circulation for the anterior spinal artery is sparse in places, certain cord segments (eg, those around the 2nd to 4th thoracic segments) are especially vulnerable to ischemia. Injury to an extravertebral feeder artery or the aorta (eg, due to atherosclerosis, dissection, or clamping during surgery) causes infarction more commonly than do intrinsic disorders of spinal arteries. Thrombosis is an uncommon cause, and polyarteritis nodosa is a rare cause.
Sudden pain in the back with tightness radiating circumferentially is followed within minutes by segmental bilateral flaccid weakness and sensory loss. Pain and temperature sensation are disproportionately impaired. The anterior spinal artery is typically affected, resulting in the anterior cord syndrome (see Table: Spinal Cord Syndromes). Position and vibration sensation, conducted by the posterior columns, and often light touch are relatively spared. If the infarct is small and affects primarily tissue farthest away from an occluded artery (toward the center of the cord), a central cord syndrome is also possible. Neurologic deficits may partially resolve after the first few days.
Infarction is suspected when severe back pain and characteristic deficits develop suddenly.
Diagnosis of spinal cord infarction is by MRI. Acute transverse myelitis, spinal cord compression, and demyelinating disorders may cause similar findings but are usually more gradual and are excluded by MRI and by CSF analysis.