case_images: PMC10776131_01
case_images: Photographs of patient 1 at presentation demonstrating Horner syndrome of the right eye with miosis and ptosis of the upper eyelid (a), followed by reversal of anisocoria and resolution of upper eyelid ptosis after instillation of topical apraclonidine 0.5% (b). Cerebral magnetic resonance angiography (c) and computed tomography angiography (d) demonstrating dissection of the right intrapetrous internal carotid artery (white arrows). Photographs at follow-up showing no more evidence of clinical (e) or subclinical (f) (using apraclonidine 0.5% pharmacologic testing) Horner syndrome.
case_images: cop-2024-0015-0001-535475_F01.jpg
case_images: PMC10776131_01_cop-2024-0015-0001-535475_F01.jpg
case_images: F1
case_images: However, a mild ptosis of the right upper eyelid was noticed, as well as a difference in pupillary size with a smaller pupil in the right eye (Fig. 1a). Reversal of anisocoria and resolution of upper eyelid ptosis of the right eye were observed after instilling three drops of apraclonidine 0.5% in both eyes, suggestive of a right Horner syndrome (Fig. 1b). A repeat exam at the ophthalmology department the next week confirmed complete resolution of the right eye eyelid ptosis and miosis (Fig. 1e). However, magnetic resonance angiography was obtained the next day and showed a narrowed eccentric lumen surrounded by a crescent-shaped mural hematoma at the intrapetrous segment of the right internal carotid artery, compatible with dissection (Fig. 1c, arrow). Apraclonidine 0.5% pharmacologic testing was repeated 6 weeks later and did no longer unilaterally dilate the right pupil (Fig. 1f). Review of the initial CT scan did reveal mild narrowing of the lumen of the intrapetrous part of the right carotid artery, surrounded by a non-enhancing crescent-shaped thickening of the vessel wall (Fig. 1d, arrow).
case_images: PMC10776131_02
case_images: Photographs of patient 2 at presentation demonstrating Horner syndrome of the right eye with miosis, ptosis of the upper eyelid, and inverse ptosis of the lower eyelid (a), followed by an asymmetric dilation of the pupils after instillation of topical cocaine 10% (b). Head computed tomography angiography (c) and MRI (d) demonstrating dissection of the right internal carotid artery at the cervical segment (white arrows). Photographs at follow-up showing no clinical signs of Horner syndrome (e), whereas cocaine 10% pharmacologic testing still produced anisocoria by dilating the uninvolved left pupil, compatible with a right subclinical Horner syndrome (f).
case_images: cop-2024-0015-0001-535475_F02.jpg
case_images: PMC10776131_02_cop-2024-0015-0001-535475_F02.jpg
case_images: F2
case_images: At presentation, drooping of the right upper eyelid was confirmed, as well as an inverse ptosis of the right lower eyelid and a difference in pupillary size (with a smaller pupil in the right eye) (Fig. 2a). Cocaine 10% pharmacologic testing showed asymmetric dilation of the pupils, suggestive of a right Horner syndrome (Fig. 2b). A closer look, however, revealed mild narrowing of the lumen at the cervical segment of the right internal carotid artery, surrounded by a crescent-shaped thickening of the vessel wall (Fig. 2c, arrow), suggesting dissection. These findings were confirmed the next day by cerebral MRI (Fig. 2d, arrow). At a follow-up examination 3 weeks later, eyelid ptosis and inverse ptosis had indeed resolved (subtle preexisting dermatochalasis of the right upper eyelid was still present), as well as the anisocoria (Fig. 2e). However, cocaine 10% pharmacologic testing still produced anisocoria (only dilating the uninvolved left pupil) and was therefore compatible with a right subclinical Horner syndrome (Fig. 2f).