Postviral Vagal Neuropathy: What Is the Role of Laryngeal Electromyography in Improving Diagnostic Accuracy?

OBJECTIVES: To investigate the convenience of laryngeal electromyography (EMG) findings in patients with chronic cough thought to be postviral vagal neuropathy (PVVN) with the clinical symptoms. STUDY DESIGN: Prospective cohort study. METHODS: We applied PVVN questionnaire and chronic cough quality of life (QoL) questionnaire, which is for determining the effect of chronic cough on the QoL, to 20 chronic cough applicants who has no explanatory cause in differential diagnosis. We also carried out videolaryngostroboscopy (VLS) and laryngeal needle EMG in these patients. RESULTS: The mean duration of persisting cough was 1.875 months (SD ±0.825). The overall mean symptom score of chronic cough questionnaire was 58.80 (SD ±9.89). There was a significant positive correlation between total EMG score and chronic cough score (Spearman r, 0.489, P < 0.05). The correlation between VLS findings and either chronic cough scores or EMG scores did not reach statistical significance. CONCLUSIONS: Cranial nerves might be affected by inflammatory processes as occur in the PVVN, which must be considered in the etiology of chronic cough. We showed that the laryngeal EMG can be used as an appropriate diagnostic tool for these patients.

Laryngeal zoster with multiple cranial nerve palsies.

A young immunocompetent patient is presented with a very rare presentation of a common viral illness: herpes zoster of the left hemilarynx with sensorial and motoric neuropathy of three ipsilateral lower cranial nerves: IX, X and XI. The mucosal lesions were discovered during upper gastrointestinal endoscopy. PCR of erosional exsudate confirmed the clinical diagnosis. Antiviral therapy and corticosteroids possibly contributed to the prosperous evolution with complete healing.

Herpes zoster laryngitis: case report and serological profile.

Compared to herpes zoster oticus, varicella zoster virus (VZV) reactivations in immunocompetent patients are rare in laryngeal region. Usually, associated vocal cord paralyses are reported. Herein is a case report of a patient with laryngeal zoster without any associated motor disorders. An attempt is made to assign the distribution of mucosal eruptions to the appropriate neuroanatomical structures. A description of the serological course of VZV IgM and IgG are provided. Vesicles were found on the left sensory distribution areas of the superior laryngeal nerve. VZV IgM and IgG antibodies reached their peak 1 month after initial symptoms. Attentive follow-up and no antiviral therapy were advocated because of the absence of any immune deficiency or endoscopic suspicion of malignancy. In this case of VZV reactivation in the sensitive area of the superior laryngeal nerve, serological profiles of VZV IgM and IgG were profoundly modified up to the fourth month.

Activity of cardiorespiratory networks revealed by transsynaptic virus expressing GFP.

A fluorescent transneuronal marker capable of labeling individual neurons in a central network while maintaining their normal physiology would permit functional studies of neurons within entire networks responsible for complex behaviors such as cardiorespiratory reflexes. The Bartha strain of pseudorabies virus (PRV), an attenuated swine alpha herpesvirus, can be used as a transsynaptic marker of neural circuits. Bartha PRV invades neuronal networks in the CNS through peripherally projecting axons, replicates in these parent neurons, and then travels transsynaptically to continue labeling the second- and higher-order neurons in a time-dependent manner. A Bartha PRV mutant that expresses green fluorescent protein (GFP) was used to visualize and record from neurons that determine the vagal motor outflow to the heart. Here we show that Bartha PRV-GFP-labeled neurons retain their normal electrophysiological properties and that the labeled baroreflex pathways that control heart rate are unaltered by the virus. This novel transynaptic virus permits in vitro studies of identified neurons within functionally defined neuronal systems including networks that mediate cardiovascular and respiratory function and interactions. We also demonstrate superior laryngeal motorneurons fire spontaneously and synapse on cardiac vagal neurons in the nucleus ambiguus. This cardiorespiratory pathway provides a neural basis of respiratory sinus arrhythmias.