Coronavirus disease‐2019 (COVID‐19), caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), is known for being a life‐threatening respiratory illnesses, but there is increasing evidence of neurological manifestations.1 Herein we report a patient with COVID‐19–associated inflammatory myopathy who presented with facial, bulbar, and proximal limb weakness.

A 58‐year‐old woman presented with cough, dyspnea, and myalgia. Vital signs were stable and her physical examination was unremarkable. Initial polymerase chain reaction (PCR) testing for SARS‐CoV‐2 was negative and the patient was discharged home. She returned 3 weeks later with more severe dyspnea, cough, dysarthria, dysphagia, odynophagia, and severe generalized weakness with inability to ambulate. She had no sensory symptoms or bowel or bladder dysfunction.

Physical examination was significant for tachycardia at 110 beats/min and oxygen saturation of 88% on room air. She had bilateral ptosis, facial weakness, hypernasal dysarthria, and profound symmetric proximal limb weakness. Reflexes were symmetrically diminished. Repeat SARS‐CoV‐2 PCR test was positive.

MRI of the entire neuroaxis showed no central or peripheral nervous system involvement, but it did demonstrate diffuse muscle edema and enhancement, with a region of myonecrosis (Figure 1A,B).

Motor nerve conduction studies of the peroneal, tibial, ulnar, and median nerves were unremarkable, as were sensory studies of the ulnar and median nerves; no responses were elicited from the superficial peroneal and sural nerves. Three‐hertz repetitive stimulation of the ulnar nerve before and after 1‐minute exercise showed no change in compound muscle action potential amplitude recorded from the abductor digiti minimi muscle during a series of 10 stimuli. Needle electromyography of the right vastus lateralis, iliopsoas, and deltoid muscles revealed sparse fibrillation potentials; no motor units could be activated.

On admission, creatine kinase (CK) was elevated to 700 U/L. Anti–Sjögren‐syndrome–related antigen (anti‐SSA) and anti–small ubiquitinlike modifier‐1–activating enzyme (anti–SAE 1) antibodies were both strongly positive and Ku antibody was weakly positive. Acetylcholine receptor (AChR) binding, modulating, and muscle‐specific kinase (MuSK) antibodies were all negative (Table 1).

Muscle biopsy showed perivascular inflammatory infiltration with endomysial extension, regenerating fibers, and upregulation of human leukocyte antigen class ABC expression on non‐necrotic fibers. Cytochrome oxidase/succinic dehydrogenase enzyme histochemistry was unremarkable. Vacuolar change and curvilinear bodies (on electron microscopy) suggestive of hydroxychloroquine myopathy were absent (Figure 1C‐F).

Our presumptive diagnosis was COVID‐19–associated myositis and a 5‐day course of 1000 mg intravenous methylprednisolone was administered. Elevated interleukin‐6 was found and tocilizumab was given. Anticoagulation was given for left brachial vein thrombosis and a 5‐day course of hydroxychloroquine and azithromycin was also administered. Over 2 weeks, her CK levels normalized and she recovered the ability to raise her arms and legs from the bed. She showed slow improvement in bulbar function and her speech became more intelligible. She did not require mechanical ventilation; however, a percutaneous endoscopic gastrostomy (PEG) tube was inserted to allow for sufficient nutrition.

Viral infection is a well‐known cause of myositis in which influenza A and B are the most common causes in the United States.2 Myopathy with elevated CK levels has been reported in patients with severe acute respiratory syndrome (SARS).3 Limited pathological studies suggested vasculitis or immune‐mediated mechanism as the potential cause for myopathy, without evidence of direct viral invasion.4, 5

Myalgias have been reported in up to a half of the patients with SARS‐CoV‐2 infection. Serum CK levels elevations depend on the severity of disease, ranging from mild to frank rhabdomyolysis.1, 6-8 A recent report described a COVID‐19 patient with myalgia, proximal weakness, elevated CK level, and muscle edema on MRI.9

Herein we have reported a COVID‐19 patient with associated myositis involving the proximal limb, bulbar, and facial muscles. The severe immune activation known to occur in COVID‐19 patients likely plays a major pathophysiological role. Myositis and myasthenia gravis (MG) may coexist and, although specific antibodies were negative and ulnar repetitive nerve stimulation was normal, the severe bulbar involvement raises the possibility of superimposed MG. This is especially of interest in light of a recent report of patients with MG and COVID‐19, one of whom was successfully extubated after treatment with tocilizumab.10 Direct viral invasion was not detected by electron microscopy. The finding of multiple serologic autoimmune antibodies is intriguing, suggesting an epiphenomenon rather than activation or unmasking of a specific immune response directed to the muscles. Further studies are needed to elucidate the mechanisms, appropriate treatment, and long‐term clinical outcomes of muscular manifestations associated with COVID‐19.

由严重急性呼吸系统综合症冠状病毒-2 (SARS-CoV-2) 引起的冠状病毒病-2019 (COVID-19) 以危及生命的呼吸道疾病而闻名，但越来越多的证据表明神经系统表现。1在本文中，我们报告了一名 COVID-19 相关炎症性肌病患者，该患者出现面部、延髓和近端肢体无力。

一名 58 岁女性因咳嗽、呼吸困难和肌痛就诊。生命体征稳定，体格检查无异常。SARS-CoV-2 的初始聚合酶链反应 (PCR) 检测结果为阴性，患者出院回家。3 周后，她再次出现更严重的呼吸困难、咳嗽、构音障碍、吞咽困难、吞咽痛和严重全身无力，无法行走。她没有感觉症状或肠或膀胱功能障碍。

体格检查显示心动过速为 110 次/分钟，室内空气氧饱和度为 88%。她有双侧上睑下垂、面部无力、高鼻构音障碍和严重的对称性近端肢体无力。反射对称性减弱。重复 SARS-CoV-2 PCR 检测呈阳性。

整个神经轴的 MRI 显示没有中枢或周围神经系统受累，但确实显示出弥漫性肌肉水肿和增强，伴有肌坏死区域（图 1A，B）。

腓骨、胫骨、尺神经和正中神经的运动神经传导研究不显着，尺神经和正中神经的感觉研究也是如此；腓浅神经和腓肠神经未引起反应。在 1 分钟运动前后对尺神经进行 3 赫兹重复刺激显示，在一系列 10 次刺激期间，从小指展肌记录的复合肌肉动作电位幅度没有变化。右侧股外侧肌、髂腰肌和三角肌的针肌电图显示稀疏的纤颤电位；无法激活任何运动单元。

入院时，肌酸激酶 (CK) 升高至 700 U/L。抗干燥综合征相关抗原 (anti-SSA) 和抗小泛素样修饰物 1 激活酶 (anti-SAE 1) 抗体均呈强阳性，Ku 抗体呈弱阳性。乙酰胆碱受体 (AChR) 结合、调节和肌肉特异性激酶 (MuSK) 抗体均为阴性（表 1）。

肌肉活检显示血管周围炎性浸润伴肌内膜延伸、再生纤维和非坏死纤维上人白细胞抗原 ABC 类表达上调。细胞色素氧化酶/琥珀酸脱氢酶组织化学无异常。提示羟氯喹肌病的空泡变化和曲线体（在电子显微镜下）不存在（图 1C-F）。

我们的推定诊断是 COVID-19 相关肌炎，并给予 1000 mg 静脉注射甲基强的松龙 5 天疗程。发现白细胞介素-6升高，给予托珠单抗。左臂静脉血栓形成给予抗凝治疗，同时给予羟氯喹和阿奇霉素 5 天疗程。2 周后，她的 CK 水平恢复正常，她恢复了从床上抬起手臂和腿的能力。她表现出延髓功能的缓慢改善，并且她的讲话变得更加清晰。她不需要机械通气；然而，插入了经皮内窥镜胃造口术（PEG）管以提供足够的营养。

病毒感染是肌炎的一个众所周知的原因，其中甲型和乙型流感是美国最常见的原因。2据报道，严重急性呼吸综合征 (SARS) 患者出现 CK 水平升高的肌病。3有限的病理学研究表明血管炎或免疫介导机制是肌病的潜在原因，但没有证据表明病毒直接入侵。4, 5

据报道，多达一半的 SARS-CoV-2 感染患者出现肌痛。血清 CK 水平升高取决于疾病的严重程度，范围从轻度到明显的横纹肌溶解症。1, 6-8最近的一份报告描述了一名 COVID-19 患者在 MRI 上出现肌痛、近端无力、CK 水平升高和肌肉水肿。9

在此，我们报告了一名 COVID-19 患者的相关肌炎，涉及肢体近端、延髓和面部肌肉。已知在 COVID-19 患者中发生的严重免疫激活可能起主要的病理生理学作用。肌炎和重症肌无力 (MG) 可能并存，虽然特异性抗体阴性且尺神经重复刺激正常，但严重的延髓受累增加了叠加 MG 的可能性。鉴于最近一份关于 MG 和 COVID-19 患者的报告，这尤其令人感兴趣，其中一名患者在接受托珠单抗治疗后成功拔管。10电子显微镜未检测到病毒直接入侵。多种血清学自身免疫抗体的发现很有趣，这表明是一种附带现象，而不是针对肌肉的特定免疫反应的激活或暴露。需要进一步的研究来阐明与 COVID-19 相关的肌肉表现的机制、适当的治疗和长期临床结果。