Horner Syndrome

  • Unilateral ptosis, miosis, and sometimes facial anhydrosis
  • Interruption of sympathetic nervous system pathway anywhere between hypothalamus and eye
  • May be isolated manifestation
  • Main causes of acute isolated Horner syndrome: spontaneous or traumatic dissection of cervical carotid artery, neck/upper chest trauma from insertion of venous catheter
  • Droopy upper lid and small but reactive pupil on same side
  • Difference in pupil size between the two eyes (anisocoria) rarely greater than 2mm
  • Ptosis rarely greater than 2mm
  • Neck pain sometimes
  • Refer patient emergently to ophthalmologist or emergency room if you find upper lid ptosis and miosis, especially if acute and accompanied by new neck pain
  • Refer patient non-emergently for chronic ptosis
  • Ophthalmologist will instill apraclonidine 0.5% or cocaine 10% into both eyes to confirm denervated iris of Horner syndrome
  • Acute isolated Horner syndrome common after neck/upper chest surgery and after insertion of central venous catheter
  • Otherwise acute isolated Horner syndrome suggests cervical carotid dissection and chance for stroke
  • Evaluation of acute isolated Horner syndrome includes emergent vascular imaging (CTA or MRA)
  • If dissection confirmed, aspirin or anticoagulant will be prescribed
  • Chronic isolated Horner syndrome may be caused by neck or paraspinal tumors, old neck/chest trauma, middle ear infection
  • Evaluation of chronic isolated Horner syndrome includes neck and upper chest imaging (CT or MRI)