# Characteristic Video Laryngeal Endoscopic "Pharyngeal Rotation" in Unilateral Pharyngeal Constrictor Muscle Paresis: A Case of Herpes Zoster Pharyngitis

## TL;DR

This paper describes a rare case of herpes zoster pharyngitis and highlights a unique endoscopic finding called 'pharyngeal rotation' that can help diagnose nerve palsy.

## Contribution

The paper introduces 'pharyngeal rotation' as a novel endoscopic sign for diagnosing unilateral glossopharyngeal/vagal nerve palsy.

## Key findings

- Pharyngeal rotation was observed during video laryngeal endoscopy in a patient with unilateral pharyngeal constrictor muscle paresis.
- The finding supported the diagnosis of glossopharyngeal/vagal nerve palsy due to herpes zoster pharyngitis.
- Serum antibody titers confirmed varicella zoster virus infection in the patient.

## Abstract

Herpes zoster pharyngitis (HZP) is a rare condition that should be considered as a differential diagnosis of acute dysphagia secondary to unilateral glossopharyngeal and/or vagal nerve palsy. Although early treatment is important to avoid adverse sequelae, serological diagnosis of varicella zoster virus (VZV) takes over a few days. Therefore, it is important to actively suspect VZV infection based on physical findings. Mucocutaneous lesions, curtain signs, and laryngeal palsy are well-known characteristic physical findings. In addition to these findings, the video laryngeal endoscopic finding that the pharyngeal constrictor muscles contract on only one side during swallowing, showing an appearance of "pharyngeal rotation", is one of the characteristic findings of glossopharyngeal/vagal nerve palsy and can support the diagnosis.

We report the case of an 82-year-old Asian female who presented with acute dysphagia, sore throat, left ear pain, and fever that persisted for several days. Initial video laryngeal endoscopy revealed a markedly decreased pharyngeal reflex and significant salivary retention without mucosal vesicular lesions. Repeat videoendoscopic evaluation of swallowing revealed characteristic pharyngeal rotation, which was helpful in diagnosing unilateral pharyngeal constrictor muscle paresis, thus suggesting unilateral glossopharyngeal/vagal nerve palsy. An increase in serum antibody titers (IgG and IgM) against VZV was observed. Bilateral differences and rotation of the pharynx during pharyngeal contraction can be detected endoscopically in pharyngeal constrictor muscle paresis caused by glossopharyngeal/vagal nerve palsy and should be evaluated during video laryngeal endoscopy in patients with dysphagia.