Bilateral Congenital Iris Sphincter Agenesis Diagnosed After Massive Bleeding Episode During Repair of Aneurysmal Dilation of Patent Ductus Arteriosus: A Case Report.

We report a rare case of an infant with both an aneurysmal dilation of the patent ductus arteriosus (PDA) and bilateral congenital iris sphincter agenesis. Her mydriasis without pupillary light reflex was first noted after a massive intraoperative bleeding episode during the PDA ligation. The assumption that the mydriasis was a sign of cerebral ischemia led to additional examinations and intensive medical therapies that in retrospect were unnecessary. This is the first reported case of combined aneurysmal dilation of a PDA and congenital iris sphincter agenesis in the anesthesia literature.