Successful Treatment of Post COVID-19 Neurogenic Dysphagia with Botulinum Toxin

Abstract

Introduction: Dysphagia in post COVID-19 patients could be caused by several factors, including reduced pharyngolaryngeal coordination due to SARS-CoV-2 tropism to the central and/or peripheral nervous system. To our knowledge, this is the first reported case of COVID-19-related dysphagia successfully treated with botulinum toxin type A injection.

Case description: We report the case of a patient with severe oropharyngeal dysphagia due to COVID-19 confirmed by fibre endoscopy. As a result, the patient required an enteral feeding tube. After two months of traditional swallowing therapies, there was only limited improvement. An electrophysiologic evaluation of the cricopharyngeal muscle was performed and showed a normal inhibition of the cricopharyngeal muscle, followed by a hypertonic rebound. Based on this result, we decided to perform a unilateral laryngeal injection of botulinum toxin type A. After the injection, the patient's swallowing function improved significantly, allowing him to return to oral feeding.

Discussion: Newly diagnosed oropharyngeal dysphagia was found in 35.3% of hospitalised patients with COVID-19. There are several possible causes of COVID-19-associated dysphagia, including stroke, encephalitis, critical illness neuropathy, Guillain-Barré syndrome and skeletal muscle injury. In our case, since stroke was excluded by brain MRI, cranial nerve injury was a possible explanation for the difficult recovery of swallowing despite daily swallowing therapy.

Conclusion: We suggest that electrophysiology is a valid tool for the diagnosis and follow-up of patients with oropharyngeal dysphagia.

Learning points: SARS-CoV-2 tropism to the central and/or peripheral nervous system can cause dysphagia in post COVID-19 patients.An electrophysiologic approach is useful for the diagnosis and follow-up of patients with oropharyngeal dysphagia.A single botulinum toxin type A injection is a valid treatment option to improve the swallowing function in patients with post COVID-19 dysphagia.

Keywords: COVID-19; EMG; botulinum toxin; dysphagia.

Figure 1

A, B) Residual is visible in post pharyngeal swallow on the epiglottis and in the retro-cricoid region. C, D) Residual enters the airway, remains above the vocal folds and is not completely ejected from the airway.

Figure 2

Electromyographic recording from cricopharyngeus and mylohyoid muscles during swallowing before botulinum toxin treatment. The cricopharyngeus muscle was recorded using a monopolar teflon-coated hollow needle, while for the suprahyoid/submental muscles surface adhesive electrodes were placed over the skin of the suprahyoid/submental region bilaterally, at an interelectrode distance of 30 mm. The black arrows indicate cricopharyngeus EMG activity inhibition corresponding to each swallowing attempt. Reproducibility of activation pattern can be appreciated across four repetitions (A to D).

Figure 3

A) Residues may be seen in pyriform right sinus, no residues remain above the vocal folds, opening of the glottis post-swallow inspiration, no stasis. B) Execution of pharyngeal swallow with rapid closure of the glottis.

Figure 4

A, B) One month after botulinum toxin treatment no food residues are visible after the administration of all kinds of textures.

Figure 5

Electromyographic recording from cricopharyngeus and mylohyoid muscles during swallowing after botulinum toxin treatment. The black arrows indicate cricopharyngeus EMG activity inhibition corresponding to each swallowing attempt. Reproducibility of activation pattern can be appreciated across four repetitions (A to D). EMG hyperactivity of cricopharyngeus muscle is clearly reduced after botulinum toxin treatment.