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Mesencephalic hemorrhage and unilateral pupillary deficit
A Shuaib1, G Israelian, M A Lee
1Foothills Hospital, Calgary, Alberta, Canada.
Journal of Clinical Neuro-Ophthalmology
|March 1, 1989
Summary
A unilateral dilated pupil can indicate midbrain bleeding. This rare finding, mesencephalic hemorrhage, should be considered in diagnosing isolated dilated pupils, even without other neurological signs.
Area of Science:
- Neurology
- Ophthalmology
Background:
- An isolated dilated and fixed pupil typically suggests ciliary ganglion dysfunction or parasympathetic nerve blockade.
- Unilateral dilated pupils are usually associated with localized neurological issues or pharmacological agents.
Observation:
- A case study of a 35-year-old woman presenting with headache and a dilated, nonreactive right pupil is described.
- Initial assessment considered common causes of isolated pupillary abnormalities.
Findings:
- Cranial computed tomography (CT) revealed a small hemorrhage in the midbrain (mesencephalon).
- A cerebral angiogram performed subsequently showed no abnormalities, ruling out vascular malformations or aneurysms.
Implications:
- This case highlights that mesencephalic hemorrhage can present as an isolated dilated pupil.
- Clinicians should include mesencephalic hemorrhage in the differential diagnosis for isolated unilateral mydriasis.
- Further research may explore the specific mechanisms linking midbrain hemorrhage to pupillary dysfunction.