Etiological evaluation of Horner syndrome in the modern imaging era and proposal for a practical algorithm

Ayse Betul Acar; Hale Zeynep Batur Caglayan1; 2; Ayse Ilksen Colpak; Murat Ucar; Taylan Altiparmak; Bijen Nazliel

doi:10.55697/tnd.2026.573

Ayse Betul Acar¹, Hale Zeynep Batur Caglayan^1,2, Ayse Ilksen Colpak³, Murat Ucar⁴, Taylan Altiparmak¹, Bijen Nazliel¹

¹Department of Neurology, Gazi University Faculty of Medicine, Ankara, Türkiye
²Neuroscience and Neurotechnology Center of Excellence Joint Application and Research Center (NÖROM), Ankara, Türkiye
³Department of Neurology, Hacettepe University Faculty of Medicine, Ankara, Türkiye
⁴Department of Radiology, Gazi University Faculty of Medicine, Ankara, Türkiye

Keywords: Horner syndrome, miosis, oculosympathetic syndrome, ptosis, pupil.

Abstract

Objectives: This study aimed to investigate the etiology in patients with Horner syndrome (HS) using neuroimaging studies based on demographic and clinical characteristics and to contribute to clinical practice by developing a practical algorithm based on our findings and integrating current neuroimaging techniques.

Patients and methods: This retrospective, two-center study evaluated 54 patients (28 males, 26 females; mean age: 49.3 ± 14.1 years; range, 21 to 76 years) with HS between January 2013 and February 2022. Demographic and clinical features of the patients, the response to apraclonidine, and neuroimaging study findings were evaluated.

Results: Of the cases included in the study, 18 (33.3%) were idiopathic, three (5.5%) were congenital, 13 (24.1%) were central (first-order neuron), 11 (20.4%) were preganglionic (second-order neuron), and nine (16.7%) were postganglionic (third-order neuron). Localized etiology was affirmed in 33 (61.8%) of 54 patients.

Conclusion: This study showed that neuroimaging methods easily identified etiology in patients with additional neurological findings in HS. The underlying causes could not be defined in a significant part of patients with isolated HS. However, it is essential to carry out detailed neuroimaging studies according to clinical findings to exclude life-threatening causes in patients with HS.

Cite this article as: Acar AS, Batur Caglayan HZ, Ilksen Colpak A, Ucar M, Altiparmak T, Nazliel B. Etiological evaluation of Horner syndrome in the modern imaging era and proposal for a practical algorithm. Turk J Neurol 2026;32(1):11-18. https://doi.org/10.55697/tnd.2026.573.