Iatrogenic Horner Syndrome Diagnosed with 0.5% Apraclonidine

Horner syndrome occurs as a result of a lesion along the oculosympathetic pathway. It has numerous potential etiologies and chemical diagnosis is classically made using topical Cocaine and Hydroxiamphetamine drops. Recent studies have proposed the use of topical Apraclonidine as a reliable and more readily available alternative to Cocaine (REF). We present a case of sudden onset Horner syndrome, diagnosed with 0.5% Apraclonidine, which was caused by improper location of a chest tube.