From the Research
Ipsilateral mydriasis after carotid endarterectomy is most likely caused by transient ischemia of parasympathetic structures within the petrous/cavernous internal carotid artery, as suggested by the most recent study 1. This condition can also be attributed to sympathetic stimulation during angioplasty, as proposed in the same study 1. The pupillary abnormality occurs because the parasympathetic fibers that constrict the pupil are compromised, resulting in unopposed sympathetic influence and subsequent pupil dilation. Key points to consider in the diagnosis and management of ipsilateral mydriasis after carotid endarterectomy include:
- Immediate neurosurgical evaluation to rule out hyperperfusion injury, as recommended by 1
- Urgent neuroimaging (CT or MRI) to identify the underlying cause, as suggested by the example answer
- Careful control of blood pressure to prevent further complications, as implied by the need to manage potential hyperperfusion syndrome
- Consideration of the possibility of a self-limiting process, especially in the absence of other focal neurologic deficits, as noted in 1 It is essential to prioritize the patient's morbidity, mortality, and quality of life when managing this condition, and to be aware of the potential for life-threatening complications, such as cerebral hyperperfusion syndrome, intracranial hemorrhage, or cerebral edema. The evidence from older studies, such as 2, 3, 4, and 5, provides additional context and possible mechanisms for ipsilateral mydriasis, including ischemia to parasympathetic structures, carotid vascular occlusion, and Horner's syndrome. However, the most recent and highest-quality study 1 takes precedence in guiding clinical decision-making.