Background: The yield of imaging in Horner syndrome has been explored only in children. This study evaluates the yield of imaging in adults.
Methods: This was a retrospective cohort study of 52 patients with Horner syndrome examined in 2 neuro-ophthalmology hospital clinics. Patients were divided into 3 groups according to the ability to determine the etiology at the time of the first neuro-ophthalmology consultation: group I, etiology of Horner syndrome known at the initial neuro-ophthalmologic examination; group II, etiology of Horner syndrome not known at the initial neuro-ophthalmologic examination, but sufficient information obtained to allow targeted imaging; and group III, etiology of Horner syndrome not known at the initial neuro-ophthalmologic examination, and sufficient information not obtained to allow targeted imaging. The yield of investigation and the frequency of the different etiologies were evaluated.
Results: In 32 (62%) patients, the etiology was already known at the initial neuro-ophthalmologic examination (group I). The most prevalent etiology was surgical trauma. In 11 (21%) patients, a targeted imaging workup was possible, revealing an etiology in 7 patients (group II). Carotid dissection and cavernous sinus mass were the most common etiologies. In 9 (17%) patients, a nontargeted imaging evaluation was necessary, revealing an etiology in only 1 patient, who had a previously undetected thyroid malignancy (group III).
Conclusions: The etiology of Horner syndrome is usually known at the time of initial presentation to a neuro-ophthalmologist. When the etiology is not known and clinical information permits a targeted imaging evaluation, an etiology can usually be determined, most commonly a cervical carotid artery dissection or a cavernous sinus mass. When the etiology is not known and clinical information is insufficient to allow a targeted imaging evaluation, an etiology is rarely discovered. Even so, nontargeted imaging is warranted because life-threatening lesions, such as thyroid malignancies, may rarely be detected.