Beware of "old" Horner syndrome.

Purpose: Chronic Horner syndrome is a rare clinical condition, the etiology of which often remains undiscovered. A patient is presented with an 8-year history of Horner syndrome who was diagnosed with multiple cervical artery dissections.

Case Report: A 42-year-old woman presented to our emergency department with a severe occipital headache that woke her up from sleep 3 days earlier. She had a history of headaches and recalled one in particular dating back to 2003. At that time, she sought medical attention at general practitioner's office because of the terrible headache and a noticeable disparity of her pupils. She was told that she had miosis of the right pupil. The examination conducted in 2011 revealed Horner syndrome with right miosis and ptosis. A four-vessel cerebral angiography revealed an occlusion of the right internal carotid artery. The morphology of stenosis and pseudoaneurysm of C1 segment of left internal carotid artery, as well as a pseudoaneurysm of V3/V4 junction of left vertebral artery indicated a probable dissective etiology.

Conclusions: This case illustrates that Horner syndrome with a chronic presentation can be as potentially dangerous as its acute counterpart and should be judiciously investigated.