SARS-CoV-2 May Not Cause Unilateral Hypoglossal Nerve Palsy After a Fortnight of Intubation.

Abstract

To the Editor: With interest, we read the article by Costa Martins et al.1 about a 24-yr-old man with severe COVID-19, neurologically manifesting as unilateral hypoglossal nerve palsy. It was concluded that unilateral hypoglossal nerve palsy can be attributed to the infection with SARS-CoV and that the case should alert clinicians for the requirement of focusing on patient’s recovery and the need for a targeted rehabilitation program.1 A number of additional points warrant consideration and are as follows. The main shortcoming of the study is that a causal relation between unilateral hypoglossal nerve palsy and COVID-19 remains unproven. Particularly, no details about magnetic resonance imaging with contrast medium of the brain or the column were reported. Investigations of the cerebrospinal fluid are missing. The patient did not undergo nerve conduction studies, needle electromyography of the tongue, or transcranial stimulation of the hypoglossal nerve. No video cinematography or oto-rhino-laryngological investigation with a fiberscope was carried out. Furthermore, unilateral hypoglossal nerve palsy has not been reported in any other COVID-19 patient among the more than 30 million infected worldwide as per the end of September 2020. A further shortcoming is that no information was provided about the current medication that the patient was regularly taking before admission, that function and morphology of other cranial nerves were not investigated, and that nerve conduction studies of peripheral nerves were not provided. To assess whether hypoglossal palsy was due to Guillain-Barré syndrome or Miller Fisher syndrome, it is crucial that more thorough investigations were carried out. Guillain-Barré syndrome is increasingly recognized as a manifestation of COVID-19, and currently, more than 60 patients with SARS-CoV-2–associated Guillain-Barré syndrome have been reported.2 Furthermore, the authors did not consider critical illness neuropathy as causative. Critical illness neuropathy is a frequent complication of long-term treatment on the intensive care unit and artificial ventilation and should be considered as a differential diagnosis in the index patient. Critical illness neuropathy may occasionally affect the cranial nerves, and affection of the brainstem in critically ill patients has been also reported.3 It is misleading to describe the patient with isolated hypoglossal nerve palsy. The patient also experienced dysphagia and dysarthria, why it is conceivable that not only the 12th cranial nerve but also the 9th and 10th cranial nerves were affected. A further shortcoming is that the medication applied during hospitalization has not been detailed. Because several drugs are potentially nerve toxic, it is crucial to know the drug treatment applied during hospitalization. The patient developed a delirium during his stay in the intensive care unit. No classification of the delirium was provided, and no results of the workup for clarifying the etiology were provided. No lumbar puncture or electroencephalography recordings were carried out. Overall, the interesting case report has a number of shortcomings, which should be addressed before drawing final conclusions. It remained unproven that the hypoglossal nerve palsy was caused by SARS-CoV-2. The patient did not exhibit palsy of a single cranial nerve but of at least three cranial nerves. More likely than isolated cranial nerve palsy, the patient had Guillain-Barré syndrome with involvement of cranial nerves or critical illness neuropathy with affection of cranial nerves. Josef Finsterer, MD, PhD Klinik Landstrasse, Messerli Institute Vienna, AustriaFulvio Alexandre Scorza, MDCarla Alexandra Scorza, MD Disciplina de Neurociência Universidade Federal de São Paulo/ Escola Paulista de Medicina (UNIFESP/EPM) São Paulo, BrazilAna C. Fiorini, MD Programa de Estudos Pós-Graduado em Fonoaudiologia, Pontifícia Universidade Católica de São Paulo (PUC-SP) São Paulo, Brazil Departamento de Fonoaudiologia Escola Paulista de Medicina/ Universidade Federal de São Paulo (EPM/UNIFESP) São Paulo, Brazil