An Unusual Cause of Fixed Dilated Pupils After Cardiac Surgery
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PRACTICAL PEARL
An Unusual Cause of Fixed Dilated Pupils After Cardiac Surgery Joseph D. Burns Æ Edward M. Manno Æ Eelco F. M. Wijdicks
Published online: 3 June 2008 Ó Humana Press Inc. 2008
Abstract Background The presence of fixed, dilated pupils after cardiac surgery is an ominous sign, typically indicating severe diffuse hypoxic-ischemic brain injury. Rarely, however, this finding can be seen as a result of focal midbrain ischemia. It is important to differentiate between these syndromes, as the latter might be amenable to acute stroke treatments, and because they affect consciousness very differently. Case A 46-year-old man with diffuse atherosclerosis underwent coronary artery bypass grafting and closure of an incidentally discovered patent foramen ovale. He underwent neurologic evaluation on post-operative day 6 because he was not speaking and appeared to have a new right hemiparesis. Eye movements, pupillary, and lid function were all normal at this time. MRI showed multiple posterior circulation infarcts, involving both cerebral peduncles. On post-operative day 12, he became unresponsive, quadriplegic, and had bilaterally fixed, dilated pupils. CT showed low attenuation in nearly the entirety of both cerebral peduncles. Discussion Midbrain infarction is rare. Bilateral midbrain infarction is even rarer and typically presents as locked-in syndrome with preservation of pupillary function and at least vertical eye movements. In our review of the literature, we found only three other cases of midbrain infarction associated with bilateral mydriasis. As in our case, these characteristically involved the anteromedial midbrain bilaterally.
J. D. Burns (&) E. M. Manno E. F. M. Wijdicks Division of Critical Care Neurology, Department of Neurology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA e-mail: [email protected]
Conclusions Fixed, dilated pupils after cardiac surgery can rarely be caused by bilateral anteromedial midbrain infarctions. It is important to differentiate this from the much more common diffuse hypoxic-ischemic injury. Keywords Midbrain Infarction DWI Ocular motility Pupils
Introduction The presence of fixed and dilated pupils after cardiac surgery is an ominous sign and typically indicates severe, diffuse hypoxic-ischemic brain injury [1]. While the former is invariably associated with severely impaired consciousness, patients with midbrain infarctions can have remarkably intact consciousness and therefore different outcomes [2]. As well, treatments differ widely for the two conditions. It is therefore crucial to recognize the difference between these problems when evaluating such patients. Here we report a patient with bilaterally fixed and dilated pupils, ophthalmoplegia, and flaccid quadriparesis associated with infarction of large portions of both sides of the anterior midbrain after cardiac surgery.
Case Report We evaluated a 46-year-old right-handed man in the cardiothoracic surgical ICU on post-operative day 6 for persistent somnolence an
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