Internal carotid dissection: Horner's syndrome

Introduction: Horner's syndrome, initially described by the Swiss ophthalmologist Johann Friedrich Horner in 1869, is a condition stemming from disruptions in the sympathetic innervation of the eye and its adjacent structures. It is characterized by the triad of classical signs: anisocoria with miosis, partial eyelid ptosis, and ipsilateral anhidrosis. While the syndrome itself does not result in visual functional disturbances, its etiology is often linked to more serious pathologies. Objective: This report aims to provide a detailed report of a patient who developed Horner's syndrome due to dissection in the internal carotid artery. The employed diagnostic examinations will be discussed for precise diagnosis, as well as the subsequent treatment. Methods: This is a descriptive and observational study, based on meticulous analysis of the patient's medical record and a thorough review of related medical literature. Results: A 48-year-old patient sought care at the health service with a report of ptosis in the right eye and frontoparietal pain on the right side, accompanied by nausea, photophobia and phonophobia. After performing a magnetic resonance angiography of the skull, a reduction in flow and dissection of the right internal carotid artery were observed, being diagnosed as dissection of the internal carotid artery. The patient had comorbidities of hypertension and hypercholesterolemia, and was treated with ASA and nortriptyline for anticoagulation and headache control. Subsequently, a diagnosis of Fibromuscular Dysplasia was made, concluding that it was a Horner's Syndrome caused by the dissection of the internal carotid artery. The patient did not require hospitalization, but remains under follow-up at Hospital de Base in São José do Rio Preto. Conclusion: Our study addresses the therapeutic approach to a clinical picture of Horner's Syndrome, discussing its etiology and describing the treatment employed, which did not involve a surgical procedure.