Not myopathic, but autonomic changes in patients with long-COVID syndrome: a case series.

INTRODUCTION: Neurological sequelae following SARS-CoV-2 infection still represent a serious concern both for neurologists and neuroscientists. In our paper, we investigated pain, myalgia, and fatigue as symptoms in long-COVID patients with an electrophysiological approach, comprising the evaluation of sympathetic skin responses (SSRs) and quantitative electromyography (qEMG). MATERIALS AND METHODS: Twelve patients were enrolled (mean age, 47.7 ± 11.6 years), referred to our attention because of myalgia, pain, or muscle cramps, which persisted about 6 months after the diagnosis of SARS-CoV-2 infection. They underwent conventional electroneurography (ENG), needle electromyography (EMG), and SSRs; moreover, qEMG was performed by sampling at least 20 motor unit potentials (20-30 MUPs) during weak voluntary contraction in deltoid and tibialis anterior muscles. The mean duration, amplitude, and percentage of polyphasic potentials were assessed and compared with healthy and age-matched volunteers. RESULTS: ENG did not disclose significant changes compared to healthy subjects; needle EMG did not reveal denervation activity. In addition, qEMG showed MUPs similar to those recorded in healthy volunteers in terms of polyphasia (deltoid: p = 0.24; TA: p = 0.35), MUP area (deltoid: p = 0.45; TA: p = 0.44), mean duration (deltoid: p = 0.06; TA: p = 0.45), and amplitude (deltoid: p = 0.27; TA: p = 0.63). SSRs were not recordable from lower limbs in seven patients (58%) and from the upper ones in three of them (25%). CONCLUSION: Our data suggest an involvement of the autonomic system, with a focus on cholinergic efferent sympathetic activity, without any evidence of myopathic changes.

Critical illness neuropathy in severe COVID-19: a case series.

INTRODUCTION: Neurological complications of SARS-CoV-2 disease have received growing attention, but only few studies have described to date clinical and neurophysiological findings in COVID patients during their stay in intensive care units (ICUs). Here, we neurophysiologically assessed the presence of either critical illness neuropathy (CIP) or myopathy (CIM) in ICU patients. MATERIALS AND METHODS: Patients underwent a neurophysiological assessment, including bilateral examination of the median, ulnar, deep peroneal and tibial motor nerves and of the median, ulnar, radial and sural sensory nerves. Needle electromyography (EMG) was performed for both distal and proximal muscles of the lower and upper limbs. In order to differentiate CIP from CIM, Direct Muscle Stimulation (DMS) was applied either to the deltoid or tibialis anterior muscles. Peak to peak amplitudes and onset latencies of the responses evoked by DMS (DMSamp, DMSlat) or by motor nerve stimulation (MNSamp, MNSlat) were compared. The ratio MNSamp to DMSamp (NMR) and the MNSlat to DMSlat difference (NMD: MNSlat - DMSlat) were also evaluated. RESULTS: Nerve conduction studies showed a sensory-motor polyneuropathy with axonal neurogenic pattern, as confirmed by needle EMG. Both MNSamp and NMR were significantly reduced when compared to controls (p < 0.0001), whereas MNSlat and NMD were markedly increased (p = 0.0049). CONCLUSIONS: We have described COVID patients in the ICU with critical illness neuropathy (CIP). COVID-related CIP could have implications for the functional recovery and rehabilitation strategies.

Brainstem neuropathology in two cases of COVID-19: SARS-CoV-2 trafficking between brain and lung.

INTRODUCTION: SARS-CoV-2 might spread through the nervous system, reaching respiratory centers in the brainstem. Because we recently reported neurophysiological brainstem reflex abnormalities in COVID-19 patients, we here neuropathologically assessed structural brainstem damage in two COVID-19 patients. MATERIALS AND METHODS: We assessed neuropathological features in two patients who died of COVID-19 and in two COVID-19 negative patients as controls. Neuronal damage and corpora amylacea (CA) numbers /mm2 were histopathologically assessed. Other features studied were the immunohistochemical expression of the SARS-CoV-2 nucleoprotein (NP) and the Iba-1 antigen for glial activation. RESULTS: Autopsies showed normal gross brainstem anatomy. Histopathological examination demonstrated increased neuronal and CA damage in Covid-19 patients' medulla oblongata. Immunohistochemistry disclosed SARS-CoV-2 NP in brainstem neurons and glial cells, and in cranial nerves. Glial elements also exhibited a widespread increase in Iba-1 expression. Sars-Co-V2 was immunohistochemically detected in the vagus nerve fibers. DISCUSSION: Neuropathologic evidence showing SARS-CoV-2 in the brainstem and medullary damage in the area of respiratory centers strongly suggests that the pathophysiology of COVID-19-related respiratory failure includes a neurogenic component. Sars-Co-V2 detection in the vagus nerve, argues for viral trafficking between brainstem and lung.

Neurological symptoms in acute COVID-19 infected patients: A survey among Italian physicians.

BACKGROUND: COVID-19 is a pandemic disease and questions rise about the coronavirus 2 (Sars-CoV-2) effect on nervous system. This involvement could help explaining the pathogenesis of this condition and lead to novel therapeutic approaches. OBJECTIVE: To assess the occurrence of neurological symptoms in COVID-19 patients during the Italian pandemic outbreak, as reported by physicians. MATERIALS AND METHODS: In the early days of pandemic emergence we developed an online survey open to all Italian clinicians involved in the diagnosis and management of COVID-19 patients. The survey was structured in three sections, with nine different items concerning the presence of different specific clinical abnormalities. Each item was graded from "absent" to "severe" in a 4-point Likert's scale. MAIN OUTCOMES AND MEASURES: Likert's scale data were analyzed by studying the distribution of responses by using medians and bar charts-relative frequencies. Also, in order to analyze differences in symptoms findings depending on the group of specialty, Likert's scale data were combined into two nominal categories ("absent"/"low" and "moderate"/"high"/") and a contingency table chi-square test was used. RESULTS: 126 physicians of 9 different medical specialties, from 10 regions of Italy, filled the online survey. The results show that 87.3% of practitioners reported neurological symptoms. In most cases these were mild and non-specific, but they were severe in a minority of patients. The most common symptoms observed were headache, myalgia and taste and smell abnormalities. Whilst there was no difference between neurologists and non-neurologists, we found that experienced clinicians (defined as clinicians that evaluated more than 30 patients) reported neurological symptoms more frequently than non-expert. CONCLUSIONS: Neurological symptoms have frequently been ported during the Italian COVID-19 pandemic, and thus should be monitored for all affected patients. Whilst some of the disturbances reported may be non-specific and common to other infectious diseases, smell and taste abnormalities might indicate nervous system as entry door for SARS-CoV-2 virus. This interpretation should promote research trials to avoid nervous system involvement.