Critical Care Medicine-Neurologic Disorders>>>>>Vascular Disorders
Question 7#

Which of the following findings on physical examination are most likely observed in post-thoracic aortic aneurysm repair spinal cord infarction?

A. Bilateral loss of proprioception in lower extremities
B. Inability to flex the knee but maintained motor function of ankle and feet bilaterally
C. Loss of sensation, motor function, and dorsalis pedis pulse in the right lower extremity
D. Flaccid paralysis at T8 level with complete loss of sensory and motor function

Correct Answer is D

Comment:

Correct Answer: D

The most common clinical presentation of a spinal cord infarction is anterior spinal artery syndrome. The anterior spinal cord is at higher risk of ischemia because of its vascular anatomy; it is supplied by a single artery with few collaterals unlike the posterior cord, which is supplied by two arteries. An infarct of the anterior spinal cord presents as loss of motor function and pain/ temperature sensation, with sparing of proprioception and vibratory sense below the level of the lesion. The acute stages are characterized by flaccidity and loss of deep tendon reflexes; spasticity and hyperreflexia develop over ensuing days and weeks. In rare cases, the paralysis may affect one leg more than the other and may be asymmetric, depending on the collateral network integrity. 

It is important to distinguish spinal cord infarction from other etiologies of postoperative neurologic deficits. Vascular occlusion (C) is a surgical emergency. It presents with lack of peripheral pulse, severe pain, and temperature change in addition to the motor deficit. The patient complains of paresthesia, which is not characteristic for anterior spinal cord syndrome. Spinal cord compression from hematoma or abscess is an important category to exclude as these often require prompt diagnosis and emergent surgical decompression (D). The clinical presentation can occur abruptly and mimic SCI. This diagnostic consideration mandates urgent magnetic resonance imaging of the spinal cord in all patients presenting with possible spinal cord infarct. 

It is important to identify the cause of a postoperative neurologic deficit to avoid delay in treatment for etiologies requiring urgent intervention such as spinal cord compression or vascular occlusion.

Reference:

  1. Mullen M, McGarvey M. Spinal Cord Infarction: Clinical Presentation and Diagnosis. UpToDate; January 09, 2018.