Vagus nerve dysfunction in the post-COVID-19 condition: a pilot cross-sectional study

OBJECTIVES

The post-COVID-19 condition (PCC) is a disabling syndrome affecting at least 5%-10% of subjects who survive COVID-19. SARS-CoV-2 mediated vagus nerve dysfunction could explain some PCC symptoms, such as dysphonia, dysphagia, dyspnea, dizziness, tachycardia, orthostatic hypotension, gastrointestinal disturbances, or neurocognitive complaints.

METHODS

We performed a cross-sectional pilot study in subjects with PCC with symptoms suggesting vagus nerve dysfunction (n = 30) and compared them with subjects fully recovered from acute COVID-19 (n = 14) and with individuals never infected (n = 16). We evaluated the structure and function of the vagus nerve and respiratory muscles.

RESULTS

Participants were mostly women (24 of 30, 80%), and the median age was 44 years (interquartile range [IQR] 35-51 years). Their most prevalent symptoms were cognitive dysfunction 25 of 30 (83%), dyspnea 24 of 30 (80%), and tachycardia 24 of 30 (80%). Compared with COVID-19-recovered and uninfected controls, respectively, subjects with PCC were more likely to show thickening and hyperechogenic vagus nerve in neck ultrasounds (cross-sectional area [CSA] [mean ± standard deviation]: 2.4 ± 0.97mm2 vs. 2 ± 0.52mm2 vs. 1.9 ± 0.73 mm2; p 0.08), reduced esophageal-gastric-intestinal peristalsis (34% vs. 0% vs. 21%; p 0.02), gastroesophageal reflux (34% vs. 19% vs. 7%; p 0.13), and hiatal hernia (25% vs. 0% vs. 7%; p 0.05). Subjects with PCC showed flattening hemidiaphragms (47% vs. 6% vs. 14%; p 0.007), and reductions in maximum inspiratory pressure (62% vs. 6% vs. 17%; p ≤ 0.001), indicating respiratory muscle weakness. The latter findings suggest additional involvement of the phrenic nerve.

DISCUSSION

Vagus and phrenic nerve dysfunction contribute to the complex and multifactorial pathophysiology of PCC.

OUP accepted manuscript

Spinocerebellar ataxias consist of a highly heterogeneous group of inherited movement disorders clinically characterized by progressive cerebellar ataxia variably associated with additional distinctive clinical signs. The genetic heterogeneity is evidenced by the myriad of associated genes and underlying genetic defects identified. In this study, we describe a new spinocerebellar ataxia subtype in nine members of a Spanish five-generation family from Menorca with affected individuals variably presenting with ataxia, nystagmus, dysarthria, polyneuropathy, pyramidal signs, cerebellar atrophy and distinctive cerebral demyelination. Affected individuals presented with horizontal and vertical gaze-evoked nystagmus and hyperreflexia as initial clinical signs, and a variable age of onset ranging from 12 to 60 years. Neurophysiological studies showed moderate axonal sensory polyneuropathy with altered sympathetic skin response predominantly in the lower limbs. We identified the c.1877C > T (p.Ser626Leu) pathogenic variant within the SAMD9L gene as the disease causative genetic defect with a significant log-odds score (Z_max = 3.43; θ = 0.00; P < 3.53 × 10⁻⁵). We demonstrate the mitochondrial location of human SAMD9L protein, and its decreased levels in patients’ fibroblasts in addition to mitochondrial perturbations. Furthermore, mutant SAMD9L in zebrafish impaired mobility and vestibular/sensory functions. This study describes a novel spinocerebellar ataxia subtype caused by SAMD9L mutation, SCA49, which triggers mitochondrial alterations pointing to a role of SAMD9L in neurological motor and sensory functions.

Current Incidence and Risk Factors of Fecal Incontinence After Acute Stroke Affecting Functionally Independent People

Background: Previously published retrospective series show a high prevalence of fecal incontinence (FI) in stroke patients. We aimed to analyze in a prospective series the current incidence of FI in acute stroke in functionally independent patients and its evolution over time and the patient characteristics associated with the appearance of FI in acute stroke. Methods: We included consecutive patients with acute stroke admitted in our stroke unit who fulfilled the following inclusion criteria: a first episode of stroke, aged >18 years, with no previous functional dependency [modified Rankin Scale (mRS) ≤ 2] and without previous known FI. FI was assessed by a multidisciplinary trained team using dedicated questionnaires at 72 ± 24 h (acute phase) and at 90 ± 15 days (chronic phase). Demographic, medical history, clinical and stroke features, mortality, and mRS at 7 days were collected. Results: Three hundred fifty-nine (48.3%) of 749 patients (mean age 65.9 ± 10, 64% male, 84.1% ischemic) fulfilled the inclusion criteria and were prospectively included during a 20-month period. FI was identified in 23 patients (6.4%) at 72 ± 24 h and in 7 (1.9%) at 90 days ± 15 days after stroke onset. FI was more frequent in hemorrhagic strokes (18 vs. 5%, p 0.007) and in more severe strokes [median National Institute of Health Stroke Scale (NIHSS) 18 (14-22) vs. 5 (3-13), p < 0.0001]. No differences were found regarding age, sex, vascular risk factors, or other comorbidities, or affected hemisphere. Patients with NIHSS ≥12 (AUC 0.81, 95% CI 0.71 to 0.89) had a 17-fold increase for the risk of FI (OR 16.9, IC 95% 4.7-60.1) adjusted for covariates. Conclusions: At present, the incidence of FI in acute stroke patients without previous functional dependency is lower than expected, with an association of a more severe and hemorrhagic stroke. Due to its impact on the quality of life, it is necessary to deepen the knowledge of the underlying mechanisms to address therapeutic strategies.

Anti-NF155 chronic inflammatory demyelinating polyradiculoneuropathy strongly associates to HLA-DRB15

Background

The aim of the research is to study the human leukocyte antigen (HLA) class II allele frequencies in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) associated with anti-neurofascin 155 (NF155) antibodies.

Methods

Thirteen anti-NF155+ and 35 anti-NF155 negative (anti-NF155neg) CIDP patients were included in a case-control study. The frequencies of the DRB1 HLA allele were analyzed in all patients while DQ frequencies were only studied in patients sharing the DRB1*15 allele. In silico HLA-peptide binding and NF155 antigenicity, predictions were performed to analyze overlap between presented peptides and antigenic regions.

Results

DRB1*15 alleles (DRB1*15:01 and DRB1*15:02) were present in 10 out of 13 anti-NF155+ CIDP patients and in only 5 out of 35 anti-NF155neg CIDP patients (77 vs 14%; OR = 20, CI = 4.035 to 99.13). DRB1*15 alleles appeared also in significantly higher proportions in anti-NF155+ CIDP than in normal population (77 vs 17%; OR = 16.9, CI = 4.434 to 57.30). Seven anti-NF155+ CIDP patients (53%) and 5 anti-NF155neg CIDP patients had the DRB1*15:01 allele (OR = 7, p = 0.009), while 3 anti-NF155+ CIDP patients and none of the anti-NF155neg CIDP patients had the DRB1*15:02 allele (OR = 23.6, p = 0.016). In silico analysis of the NF155 peptides binding to DRB1*15 alleles showed significant overlap in the peptides presented by the 15:01 and 15:02 alleles, suggesting functional homology.

Conclusions

DRB1*15 alleles are the first strong risk factor associated to a CIDP subset, providing additional evidence that anti-NF155+ CIDP patients constitute a differentiated disease within the CIDP syndrome.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0996-1) contains supplementary material, which is available to authorized users.

Abstract TP7: Somatosensory Evoked Potentials and Dramatic Recovery After Mechanical Thrombectomy in Patients With Acute Ischemic Stroke and Anterior Large Vessel Occlusion

Hypothesis: Somatosensory evoked potentials (SEPs), as surrogate of cerebral blood flow, may predict immediate and long term clinical outcome in patients with acute ischemic stroke undergoing mechanical thrombectomy.

Methodology: Median nerve SEPs were monitored before and continously during mechanical trhombectomy in acute ischemic stroke patients with proximal anterior large vessel occlusion. The target signal was the patency of the N20 wave ipsilateral to the stroke site. Dramatic recovery was defined as improvement ≥ 10 or NIHSS score 0-1 at 24 hours and good functional outcome as modified Rankin scale 0-2 at 90 days.

Results: A total of 41 patients were monitored with SEPs. Six patients were excluded because of traces artifacts. At the beginning of the procedure, patent N20 was observed in 25 patients and absence of N20 wave in 10 patients. Age, gender, median NIHSS score (17 vs 17), site of vessel occlusion, IV tPA use, ASPECTS score and onset-to-groin puncture time were comparable between patients with patent and absent N20 wave. Patent N20 group showed better median NIHSS score at 24 hours (6 [2-18] vs 18 [11-24], p=0.031) and a no significant trend to a higher rate of dramatic recovery (52% vs 25%, p=0.087). At the end of the procedure, patent N20 was found in 25 patients (3 recovered N20 and 3 lost N20 wave). Complete revascularization (TICI 2b,3) was achieved in 22/25 patent N20 group and 4/10 no patent N20 group. Patent N20 at the end of the procedure was significantly associated with dramatic recovery (60% vs 0%, p=0,001) and good functional outcome (68% vs 0%, p=0,001)

Conclusions: SEPs recording is a non-invasive and feasible test that provides real time data in the angiosuite, even in patients under general anesthesia in which neurological deficit cannot be evaluated. Patency of SEP at the beginning but especially at the end of the procedure is related with immediate and long term outcome, despite achieving complete revascularization.