Horner syndrome can be caused by which of the following?

• A. Headaches or migraines
• B. Mass
• C. Inflammation
• D. All of the above

Answer: (D)

Horner syndrome happens when the sympathetic nerves that run to the eye are interrupted anywhere along their route from the brain down to the eye. This oculosympathetic pathway can be affected by a variety of issues. A mass in the neck or chest can press on or invade the sympathetic fibers, and masses in the apex of the lung (like Pancoast tumors) are a classic cause. Inflammation in the area of the sympathetic chain can also disrupt transmission, leading to the characteristic ptosis and miosis. Some headaches, especially cluster-type headaches, can present with Horner’s features because of associated autonomic symptoms that involve the same sympathetic pathways. Since any process that disrupts this pathway can produce Horner syndrome, headaches, masses, and inflammation are all potential contributing factors, making all of the listed options plausible.