Anisocoria in Traumatic Brain Injured Patient.
American Journal of Physical Medicine & Rehabilitation
Case Diagnosis: Anisocoria
Case Description: A 54-year-old male presented following an assault with loss of consciousness for an unknown period of time. Glascow coma scale was 13 on arrival to the Emergency Department. Imaging showed right subarachnoid hemorrhage, trace left subdural hemorrhage, and left medial orbital wall fracture. Physical exam showed his pupils were equally round and reactive to light. On the third day of admission, his left pupil was found to be dilated and nonreactive. Patient offered no new subjective complaints and his neurological exam was otherwise stable. Repeat head imaging showed only stable hemorrhages. Ophthalmology reviewed prior facial CT and could not identify any injury along the cranial nerve III pathway. Following ophthalmological examination he was diagnosed with traumatic mydriasis.
Discussions: The clinical significance of anisocoria can range from completely benign to immediately life threatening. A systematic approach is required to identify the potential severity of a situation and help direct testing appropriately. Traumatic mydriasis is pupillary dilation following ocular trauma and usually results from injury to the pupillary sphincter muscle. The ability of the pupil to react to light and accommodate varies, however defect is present in both direct and consensual light. The absence of ptosis and diplopia are important distinctions. Some differentials include physiological anisocoria, pharmacologic mydriasis, third nerve palsy, and intracranial pathology. Traumatic mydriasis is a diagnosis of exclusion and more serious etiologies must be ruled out.
Conclusions: Traumatic mydriasis can occur following blunt eye trauma due to injury to the pupillary sphincter muscle. It is a diagnosis of exclusion, and more serious causes must be ruled out. Thorough examination, documentation, and expert opinion from consultants can aid in proper diagnosis and limit unnecessary repeat testing.
McCallum J, Sankovic R, Contreras W. Anisocoria in traumatic brain injured patient. Am J Phys Med Rehab. 2021;100(4 suppl.):a31.