Stroke is caused by a loss of blood circulation to an area or areas of the brain. The specific neurologic deficits may vary depending on the location, extent of the damage, and cause of the disorder. A carotid dissection is when a carotid artery develops a tear in its lining. The flow of blood in between the various layers of the blood vessel causes the layers to separate, resulting in the lumen (channel) narrowing.

Stroke secondary to carotid dissection, unlike many other forms of stroke, may occur in young people, usually under 40 years old. Dissection accounts for less than 5% of strokes.

The risks for stroke secondary to carotid dissection include a history of disorders that cause weakness of the blood vessels, such as Marfan's syndrome, fibromuscular dysplasia, and others. Risks also include injury or trauma of the neck. Invasive procedures that involve the carotid artery (e.g., arteriogram) can also put someone at risk.

• pain
  • may occur prior to other neurologic deficits
  • may be in neck
  • may radiate into eye
• pulsating noises may be present in the ear (pulsatile tinnitus)
• weakness or total inability to move a body part
• abnormal sensations
  • numbness, loss of sensation
  • tingling or other
• Horner's syndrome
  • eyelid drooping (ptosis)
  • abnormal pupil
  • abnormal facial sweating
• decreased or lost vision, partial or temporary
• language difficulties (aphasia)
• inability to recognize or identify sensory stimuli (agnosia)
• loss of memory
• vertigo (abnormal sensation of movement)
• loss of coordination
• swallowing difficulties
• personality changes
• mood and emotion changes
• consciousness changes
  • sleepy
  • stuporous, somnolent, lethargic
  • comatose, unconscious

Findings may include any number of deficits. These can include abnormal vision, movement, sensation, reflexes, and speaking. Occasionally, these findings fluctuate with time, depending on how much blood flow is impaired at the moment they are measured.

An examination should include testing of all neurological functions, including visual, motor, sensory, and cognitive abilities, to determine the specific deficits present. The examination may show changes in vision or visual fields, changes in reflexes including abnormal reflexes or abnormal extent of "normal" reflexes, abnormal eye movements, muscle weakness, decreased sensation, and other changes.

A bruit, an abnormal sound heard with the stethoscope, may be heard over the carotid arteries of the neck. The blood pressure may be high. Horner's syndrome may occur, which involves a small pupil, drooping of one eyelid, lack of sweating on one side of the forehead, and a sunken appearance to one eye.

Tests (see also tests for stroke):

• MRI or CT of the head to determine extent and location of stroke
• a cerebral angiography reveals changes indicating carotid dissection
• MRA or a duplex/Doppler ultrasound can also detect dissection
• Blood tests to determine if there are abnormalities in connective tissue or genetic causes of abnormal blood vessels