Horner Syndrome With a Positive Harlequin Sign in an Adolescent Male

An 11-year-old boy presented to the emergency department with a history of uneven facial flushing. The boy's parents described that the left side of his face became flushed with exercise while the right side remained pale. On clinical examination, the boy had right-sided ptosis and miosis, with pupils measuring 5.0 mm on the right eye and 8.0 mm on the left eye (Fig. 1).

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Guor Wang, MD Horner Syndrome With a Positive Harlequin Sign in an Adolescent Male Mitchell D. Thatcher, BSc, Lindsay Ong-Tone, MB ChB, FRCSC A n 11-year-old boy presented to the emergency department with a history of uneven facial flushing. The boy’s parents described that the left side of his face became flushed with exercise while the right side remained pale. On clinical examination, the boy had right-sided ptosis and miosis, with pupils measuring 5.0 mm on the right eye and 8.0 mm on the left eye (Fig. 1). Pupils were otherwise round, reactive, and without afferent pupillary defects. Anhidrosis was suspected on the right side but was not formally assessed. Further examination revealed 20/25 corrected vision in both eyes, complete extraocular movements, and full confrontational fields to finger counting. Anterior and posterior segment examinations were normal. General examination revealed normal tone, reflexes, and cranial nerve function. A photograph taken by the parents before presenting to the emergency department showed distinct hemifacial flushing (Fig. 2). Neuroimaging studies, including MRI and MRA, of the brain, neck, and upper chest, with and without contrast were unremarkable. The etiology of this patient’s presentation is unclear, but the parents recalled a recent history of right shoulder injuries at a trampoline park and in a snowmobile accident, suggesting a possible traumatic cause. Before these injuries, they had never noticed the ptosis, miosis, or hemifacial flushing with exercise. Based on the clinical signs, the boy was diagnosed with Horner syndrome with a positive Harlequin sign and was managed conservatively by ophthalmology and child neurology. At 4 years of follow-up, the patient’s family reported that the ptosis and hemifacial flushing had resolved, and only mild anisocoria remained. Horner syndrome is characterized as the classical triad of ptosis, miosis, and anhidrosis (1). Additionally, the Harlequin sign describes the distinct hemifacial flushing that may occur with oculosympathetic findings (such as Horner syndrome) or without (referred to as “Harlequin syndrome”) (2). The Harlequin sign arises due to sympathetic dysfunction that pre- FIG. 1. Right-sided ptosis and miosis of Horner syndrome. vents thermoregulatory vasodilation on the denervated side. The flushed side has normal innervation and occurs as a compensatory reaction to the lack of sudomotor and College of Medicine (MDT), University of Saskatchewan, Saskatoon, Canada; and Division of Ophthalmology (LOT), Department of Surgery, University of Saskatchewan, Regina, Canada. The authors report no conflicts of interest. Address correspondence to Mitchell D. Thatcher, BSc, 215 2125 11th Avenue, Regina, SK S4P 3X3, Canada; E-mail: Mitchell.Thatcher@ usask.ca FIG. 2. Photograph of the patient after exercise with the hemifacial flushing of the Harlequin sign. Thatcher and Ong-Tone: J Neuro-Ophthalmol 2022; 42: e579-e580 e579 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence Furthermore, the extended follow-up of this pediatric case is unique as the family stated that the flushing had resolved 4 years after the initial presentation, possibly representing a weakening of the compensatory sudomotor and vasomotor mechanisms of the normally innervated side of the face. Disorders of the facial sympathetic nervous system may present with concerning clinical signs that require a comprehensive investigation. Although many causes of Horner and Harlequin syndrome are benign, it is essential to rule out more sinister pathologies, such as acute bleeding, thrombosis, syrinx, or compressive tumors (2), with a comprehensive neurological examination and appropriate imaging studies. In the case of normal investigations, patients should be followed closely but reassured of the syndromes’ benign nature and likely improvement over time. vasomotor function on the pale side (3). In our case, we suspect a lesion to the sympathetic system along the right side, correlating to a right-sided ptosis and miosis, with a contralateral flushing reaction on the left side. Further reviewing the anatomy of the facial sympathetic nervous system allows us to better localize the lesion for this clinical presentation. In the facial sympathetic system, preganglionic oculomotor fibers leave the spinal cord at T1, while sudomotor and vasomotor fibers exit at T2 and T3 of the spinal cord. The fibers ascend the sympathetic chain to synapse with the superior cervical ganglion at the C2 and C3 levels. Thirdorder neurons exit rostrally along the internal carotid artery and innervate the eye and forehead. Caudally exiting neurons travel with the external carotid artery to supply the rest of the face (4). Therefore, the presence of an isolated Harlequin syndrome would suggest a lesion of the second-order preganglionic sudomotor and vasomotor fibers between the upper thoracic roots and the bifurcation of the common carotid artery. Alternatively, the coexistence of Horner syndrome (as seen in this case) suggests a lesion to, or just proximal to, the superior cervical ganglion. Here, we present a case of an adolescent male child with Horner syndrome and an accompanying Harlequin sign due to a presumed traumatic cause. Our case aligns with a review of published Harlequin syndrome cases, where most patients also had abnormal pupils, most commonly Horner syndrome (5). The current case is unique due to the presumed traumatic cause of the syndrome in an adolescent that was not due to surgical intervention or a complication of anesthesia. 1. Walton KA, Buono LM. Horner syndrome. Curr Opin Ophthalmol. 2003;14:357–363. 2. Miquel J, Piyaraly S, Dupuy A, Cochat P, Phan A. Congenital cases of concomitant harlequin and horner syndromes. J Pediatr. 2017;182:389–392. 3. Drummond PD, Lance JW. Facial flushing and sweating mediated by the sympathetic nervous system. Brain. 1987;110(pt 3):793–803. 4. Darvall JN, Morsi AW, Penington A. Coexisting harlequin and Horner syndromes after paediatric neck dissection: a case report and a review of the literature. J Plast Reconstr Aesthet Surg. 2008;61:1382–1384. 5. Bremner F, Smith S. Pupillographic findings in 39 consecutive cases of harlequin syndrome. J Neuroophthalmol. 2008;28:171–177. e580 Thatcher and Ong-Tone: J Neuro-Ophthalmol 2022; 42: e579-e580 REFERENCES Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.