LAUSR

ABSTRACT Horner’s syndrome coexisting with an ipsilateral fourth cranial nerve palsy is a rare occurrence and likely localises to pathology in the cavernous sinus. One such case may have occurred in the 18th century affecting the renowned mathematician Leonhard Euler. A review of his biographies, eulogies, and three finely detailed facial portraits suggest that these two neuro-ophthalmic conditions, along with visual loss and a decades-long intermittent febrile illness, may have been the result of an orbital cellulitis and septic cavernous sinus thrombosis, from an underlying chronic brucellosis infection.