Point-of-Care Ultrasound for Quantitative Assessment of Pupillary Dysfunction in Acute Internal Carotid Artery Dissection

Diagnosing internal carotid artery dissection (ICAD) can be challenging even for experienced clinicians, as one of its most specific signs-Horner syndrome (HS)-is often missed during routine neurological examination (NE). This study aimed to evaluate pupillary reactivity in ICAD patients using ultrasound pupillometry (UP) and compare quantitative UP findings with standard NE.

We enrolled 33 consecutive patients with acute ICAD and an age- and sex-matched healthy control group without ocular pathology. HS was assessed at admission using standard NE. UP was performed in both the affected eye (AE) and non-affected eye (NAE), measuring pupillary diameter (PD) and response time (PT) to light stimulus (LS) and ciliospinal reflex (CR). Ultrasound examinations were performed by a single operator, while all offline quantitative measurements were performed by a second investigator blinded to the neurological findings.

UP revealed significantly smaller PDs in the AE compared with the NAE, both at rest and after direct and consensual LS (3.23 ± 0.64 mm vs. 5.12 ± 0.51 mm, p < 0.01). The AE also showed reduced CR response in terms of mydriasis (4.03 ± 2.8% vs. 9.76 ± 3.36%, p < 0.01) and dilation time (2.984 ± 0.278 s vs. 2.071 ± 0.223 s, p < 0.01). Similar differences were observed between the AE and controls. Quantitative pupillary abnormalities were identified by UP in 96.9% of patients, whereas clinical HS was detected by standard NE in 39.4% (p < 0.01).

UP represents a promising Neuro-POCUS application for the objective, quantitative assessment of pupillary dysfunction in acute ICAD and may serve as a valuable adjunct to routine NE.