Horner Syndrome and Anisocoria

Primary Demographics

• Pediatrics: traumatic (especially following birth) or neoplastic (neuroblastoma, gliomas)

• Adults: intracranial pathology (first order), thoracic pathology (second order), internal carotid artery and cavernous sinus pathology (third order)

What am I looking for?

• Exam

  • Ptosis, miosis of the affected side, anhidrosis, iris heterochromia (pediatrics), ophthalmoplegia

• History

  • Onset of ptosis or miosis, functional neurologic deficits, history of trauma or neck injury, headache or neck pain, photos to see if ptosis was present earlier

Management

• Diagnosis is the most challenging part of Horners and anisocoria (memorize the flow chart)

  • Anisocoria greater in dark

    • Presence of dilation lag of the affected eye in dark suggests Horners

    • 0.5% Apraclonidine in both eyes will lead to dilation of the affected eye

      • Overnight this is sufficient and should prompt immediate imaging

  • Once diagnosis confirmed as Horners

    • MRI brain and orbits wwo contrast

    • CTA or MRA head and neck (rule out dissection)

    • CT or MR chest

    • Full body imaging in children

  • Anisocoria greater in light

    • Presence of constriction lag of the affected eye in light suggests a parasympathetic lesion

    • Dilute 1% pilocarpine with BSS (1:10) and apply to eyes.

      • Constriction suggests an Adie's pupil (benign), failure to constrict should prompt use of 1% pilocarpine

      • Constriction with 1% pilocarpine is consistent with a CN III palsy, failure to constrict suggests pharmacologic mydriasis. 

Follow up: depends on clinical findings causing anisocoria