A 35-year-old man is brought to the emergency department after crashing his motorcycle into a guardrail at high speed. He was riding without a helmet and briefly lost consciousness, but he is now awake and alert in the emergency department. Blood pressure is 120/70 mm Hg and pulse is 96/min. The patient is wearing a cervical collar and his breath smells of alcohol. Bilateral pupils are equal and reactive. There is chest wall bruising and tenderness. Heart and breath sounds are normal. The abdomen is soft and nontender. There is an obvious deformity of the right leg. Neurological examination shows bilateral lower extremity weakness. Light touch and vibratory sensation is present in both legs, but there is loss of pain and temperature sensation. Bilateral upper extremity motor and sensory examination is normal. Injury at which of the following sites is the most likely cause of this patient's neurological deficits?

Question

A 35-year-old man is brought to the emergency department after crashing his motorcycle into a guardrail at high speed.  He was riding without a helmet and briefly lost consciousness, but he is now awake and alert in the emergency department.  Blood pressure is 120/70 mm Hg and pulse is 96/min.  The patient is wearing a cervical collar and his breath smells of alcohol.  Bilateral pupils are equal and reactive.  There is chest wall bruising and tenderness.  Heart and breath sounds are normal.  The abdomen is soft and nontender.  There is an obvious deformity of the right leg.  Neurological examination shows bilateral lower extremity weakness.  Light touch and vibratory sensation is present in both legs, but there is loss of pain and temperature sensation.  Bilateral upper extremity motor and sensory examination is normal.  Injury at which of the following sites is the most likely cause of this patient's neurological deficits?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d552_2517_bc81_4d102e33f9e9_MD0003_00 This patient with neurological deficits after a motorcycle crash likely has anterior cord syndrome. This usually occurs when there is an injury to the anterior spinal artery (eg, disc retropulsion, fragments of bone from vertebral burst fracture) affecting the anterior two thirds of the spinal cord. Neurological findings include: Bilateral hemiparesis: Lateral corticospinal tract; at the level of the cord injury and below Diminished bilateral pain and temperature sensation: Lateral spinothalamic tract (LST); 1-2 levels below the cord injury because LST decussates 1-2 levels before the corresponding level Intact bilateral proprioception, vibratory sensation, and light touch: Dorsal columns; blood is supplied from the posterior spinal arteries, which are bilateral and reinforced by radicular segmental branches In this patient, bilateral upper extremity motor and sensory examination is normal, which indicates that the level of injury is likely below T1, based on the dermatomes that innervate the arms. This patient should immediately have an MRI to assess the injury site, and likely needs a decompressive procedure to regain neurological function. dermatomes (Choice B) Central cord syndrome is characterized by decreased sensation and motor function in the arms with relative sparing of the legs after forced hyperextension (eg, fall, whiplash); it can be associated with bladder dysfunction. It is usually seen in the elderly with underlying cervical spondylotic myelopathy. (Choice C) An injury to the frontoparietal lobes is likely to cause ongoing altered consciousness, and alone is unlikely to cause bilateral lower extremity weakness with sensory changes. (Choice D) A spinal nerve root injury affecting the lower extremities is more likely to cause a unilateral sciatica-type presentation of back pain, changes in sensation, and motor weakness in one extremity rather than in both. (Choice E) Ventral brainstem injury can lead to "locked-in" syndrome, a disorder characterized by quadriplegia and the inability to speak or swallow but with normal consciousness. Patients can usually blink voluntarily and look vertically due to sparing of the supranuclear ocular pathway. Educational objective: Anterior cord syndrome usually occurs when there is injury to the anterior spinal artery from trauma. It is characterized by bilateral motor function loss at and below the level of the injury with diminished pain and temperature sensation bilaterally that begins 1-2 levels below the cord injury, whereas proprioception, vibratory sensation, and light touch are unaffected. References: Characterization of spinal injuries sustained by American service members killed in Iraq and Afghanistan: a study of 2,089 instances of spine trauma. (http://www.ncbi.nlm.nih.gov/pubmed/23511153) [Pathophysiology of acute spinal cord injury]. (http://www.ncbi.nlm.nih.gov/pubmed/16607070)

A 35-Year-Old Man Is Brought to the Emergency Department After