The opposite pupil in herniation

Ropper, Allan H. MD

Neurological/Neurosurgical Intensive Care Unit, Massachusetts General Hospital, Boston, MA.

Address correspondence and reprint requests to Dr. Allan H. Ropper, St. Elizabeth's Hospital, 736 Cambridge Street, Boston, MA 02135.

Received March 2, 1990. Accepted for publication in final form April 17, 1990.

Neurology 40(11):p 1707-1709, November 1990.

Article abstract

I serially examined the pupil opposite the one already enlarged from transtentorial herniation in 13 patients. The main abnormalities, stereotyped in most patients, were an initially diminished light reaction with a 2.5- to 4-mm-diameter pupil, followed by slight reduction in size, and then reenlargement to greater than original size, all with preserved roundness. Subsequent deterioration varied among patients, but a transitional oval shape was infrequent and oculomotor function was preserved until both pupils were enlarged and fixed. Once the pupil on the side of a mass enlarges, heralding herniation, subsequent deterioration can be appreciated through changes in'reactivity and size of the opposite pupil.