Chronic Horner’s in a patient with internal carotid artery dissection and pseudoaneurysm AUTHOR: Stephanie Rettenmeier, OD

ABSTRACT: A patient presents with a chronic right Horner’s pupil secondary to an asymptomatic right internal carotid artery dissection and resultant pseudoaneurysm. Following is a discussion of diagnosis and management of patients with Horner’s syndrome. GENERAL CASE HISTORY: • Patient Demographics: 46 year old Caucasian male • Chief Concern: Increase in frequency of right temporal and retrobulbar headaches • Ocular History: Chronic right sided Horner’s pupil, longstanding right temporal and retrobulbar headaches, , , and • Medical History: Hyperglycemia, obstructive sleep apnea, obesity, hypertension, carotid artery /dissection, and chronic headache • Medications: Carboxymethylcellulose 0.5% ophth soln. PRN, Metformin HCL 500mg BID • Other: No history of ocular surgeries or trauma to the eyes, neck, or head; surgical history includes discectomy PERTINENT EXAM FINDINGS: • Clinical: Best corrected visual acuity was 20/20-2 OD and 20/25 OS. o Entrance testing was remarkable for 2mm of anisocoria. were round and reactive to light with no afferent pupillary defect OU. His pupil sizes were measured in dim and bright light, respectively: OD: 5mm/3mm, OS: 7mm/5mm. The 2mm anisocoria was first documented in January 2008. A positive 10% test confirmed a right sided Horner’s pupil in February 2008. o External examination showed mild right upper stable to previous records. Anterior segment revealed trace right upper eyelid edema with bilateral dermatochalasis of the upper . Posterior segment findings were unremarkable. • Physical: No history of right facial anhydrosis. He is symptomatic of chronic migraine headaches as well as right temporal and retrobulbar headaches, controlled with rest. • Laboratory Studies: The patient has a history of abnormal (high) triglycerides, hemoglobin A1C, and fasting blood glucose • Radiology Studies: Serial imaging in the form of MRI and MRA have been performed on the patient from 07/2010 to 08/2016 showing evidence of a right petrous internal carotid artery (pseudo)aneurysm. Serial imaging shows decrease in overall size of the aneurysm from 20mm x 10mm in 2010 to 12mm x 7mm in 2016; all imaging studies report stability of the lesion. DIFFERENTIAL DIAGNOSIS: • Anisocoria: Adie (tonic) pupil, , third nerve palsy, chronic anterior , sphincter tear, physiological anisocoria, unilateral exposure to miotic or mydriatic agents1 DIAGNOSIS AND DISCUSSION • Condition: Horner’s syndrome presents after disruption along the oculosympathetic pathway causing the classic triad of pupillary , mild ptosis, and facial anhydrosis2,5. Common causes of preganglionic disruptions include Pancoast tumor, trauma, or post (para)thyroid surgery4. Common causes of postganglionic disruptions include trauma, cluster/migraine headache, or internal carotid artery dissection/aneurysm4. • Diagnosis: A combination of patient history, pharmacological testing, and diagnostic imaging help determine the diagnosis and etiology2. Clinically, 1% can confirm a Horner’s pupil, though classically 10% topical cocaine is used when available4,5. Pharmacologic testing to localize the lesion is less common due to poor availability of hydroxyamphetamine; targeted neuroimaging is being utilized in its place4. Imaging produces useful results when used in conjunction with the patient’s signs and symptoms and hydroxyamphetamine testing to distinguish pre- versus post-ganglionic disruption5. • Unique Features: This case discusses a Horner’s pupil in a younger patient, asymptomatic for signs of carotid dissection; neuroimaging was required for diagnosis. A painful Horner’s pupil is the primary sign in up to 60% of cases caused by internal carotid artery dissection3,5. Carotid artery dissection most commonly occurs in patients 35-50 years old3. TREATMENT AND MANAGEMENT • Treatment: The patient was monitored with annual serial imaging using MRI & MRA. After stability was observed, imaging was spread out to a bi-annual basis. Treatment of 81mg of aspirin daily was initiated for stroke prevention. It was also recommended that the patient control any hypertension, hyperglycemia, and hypercholesterolemia. • Treatment should be provided based on the etiology of the condition. In cases of carotid dissection or aneurysm, stroke prevention is required. It is estimated that 20% of strokes are caused by carotid artery dissection in patients younger than 45 years old3. CONCLUSION • Use the patient history to help determine the etiology. Up to 80% of patients have apparent etiology at the time of diagnosis2; when it is not an obvious etiology, targeted neuroimaging can be useful to rule out life-threatening pathology5. • Consider carotid artery dissection, especially in patients who present with headache or in younger aged patients. Carotid dissection should be ruled out when the etiology is unknown, because certain cases can present with few symptoms. BIBLIOGRAPHY 1. Gerstenblith AT, Rabinowitz MP. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of . Sixth ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012. 2. Davagnanam I, Fraser CL, Miszkiel K, Daniel CS, Plant GT. Adult Horner’s syndrome: a combined clinical, pharmacological, and imaging algorithm. Eye. 2013;27(3):291-298. 3. Morgan RD, Kreckler S, Lintott P. Painless Horner’s syndrome through occupational exposure. Am J Med. 2011;124(6):e5-6. 4. Gao Z, Crompton JL. Horner syndrome: a practical approach to investigation and management. Asia-Pac J Ophthalmol. 2012;1(3):175-179. 5. Kedar S, Biousse V, Newman NJ. Horner syndrome. UpToDate. http://www.uptodate.com/contents/horner-syndrome. Updated Jul 14, 2015. Accessed August 16, 2017.