683 An Aberrant Retropharyngeal Internal Carotid Artery (ICA) Associated with Airway Obstruction: A Case Report

Abstract Background The ICA ascends towards the skull base in the carotid sheath, posterolateral to the posterior pharyngeal wall. Various patterns of congenital and acquired ICA anomalies in relation to the pharynx have been described in the literature. Very few studies have associated these anatomical variations with clinical symptoms of airway obstruction. Case report An 85-year-old female patient presented to Accident & Emergency (A&E) with a recent history of several discrete episodes of positional airway obstruction on leaning forward. The description of symptoms from patient and first responders was consistent with stridor. No other relevant medical history was identified. Flexible nasal endoscopic examination (FNE) revealed a smooth pulsatile lesion in the posterior pharyngeal wall. No other abnormality was detected. CT head and neck characterized an anatomically aberrant and tortuous internal carotid artery in the retropharynx, partially obstructing the oropharynx/supraglottis. The patient was monitored for 48 hours without incident. No further treatment was recommended due to her frailty, and she was discharged with a telephone follow up. Conclusions Although causality cannot be proven, the partial obstruction of her airway by a large aberrant ICA vessel provides a likely explanation for her symptoms. No other cause for her symptoms was identified. This interesting case presents an unusual differential diagnosis for positional airway obstruction. It also highlights a rare but important anatomical variation in the path of the ICA which ought to be considered during oropharyngeal or laryngeal surgery to avoid catastrophic arterial injury.