Myasthenic crisis in the setting of Coronavirus Disease 2019 (COVID-19).

In December 2019, bronchoalveolar lavage fluid from a number of patients in Wuhan, China identified a novel beta-coronavirus, known as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), leading to the syndrome known as Coronavirus Disease 2019 (COVID-19) [1]. A patient with Myasthenia Gravis (MG) on immunosuppressive or immunomodulatory therapy with underlying respiratory muscle compromise may be more susceptible to infection with COVID-19 or severe manifestations of the virus. We present the case of an 80-year-old SARS-CoV-2 positive patient with MG who presented with respiratory failure and required eventual tracheostomy for subsequent myasthenic crisis (MC). The patient's family provided informed consent to publish this manuscript.

An 80-year-old male with a history of hypertension, diabetes and MG on azathioprine and monthly intravenous immunoglobulin (IVIG) presented with SpO2 88%, respiratory distress, fever 101 °C, and increased work of breathing. Chest radiography revealed bilateral lower lobe opacities, and SARS-CoV-2 polymerase chain reaction testing was positive. He was intubated on the day of arrival for hypoxic respiratory failure and managed for COVID-19. As part of this treatment, he received azithromycin for four days and hydroxychloroquine for seven days; azathioprine was held. Following 6 days of mechanical ventilation, he was successfully extubated to a non-rebreather mask and maintained an SpO2 between 90 and 100%. Four days after extubation, the patient's mental status and ability to participate in self-care declined, and an aspiration event required re-intubation. It was unclear whether the patient's acute decompensation was representative of a biphasic evolution of COVID-19 infection or complications of MG.

Serial physical exams demonstrated progressive proximal limb weakness with preserved distal limb reflexes. Vital capacity (VC) measured at this time was approximately 15 mL/kg, and the patient was diagnosed with MC. Hydroxychloroquine was discontinued and the patient was started on pyridostigmine, followed by five days of daily IVIG. Despite some return of strength, minimal FiO2 and positive end expiratory pressure (PEEP) requirements, he failed multiple spontaneous breathing trials and ultimately required open surgical tracheostomy on day 20 of admission. Repeat COVID-19 testing 3 weeks following admission remained positive.

Although the majority of COVID-19 patients have mild symptoms, a subset can develop pneumonia and respiratory distress, requiring noninvasive or invasive ventilation, and potential extracorporeal membrane oxygenation (ECMO) [1]. Early tracheotomy is suggested for critically ill ventilated patients with COVID-19, as it increases liberalization from the ventilator, decreases ICU length of stay, risk of subglottic stenosis and need for sedation. We suspect the patient developed MC based on his progressive proximal muscle weakness, preservation of distal reflexes, reduced vital capacity and subsequent respiratory failure. Among the risk factors for development of MC are use of macrolide and quinolone antibiotics, both of which this patient received as the recommended treatment for COVID-19. An alternative explanation for this patient's subsequent deterioration is a biphasic presentation of COVID-19 infection, although less likely.

A VC <1 L (or <20–25 mL/kg), peak expiratory flow <40 cm H2O, or a negative inspiratory force <20 cm H2O indicates significant respiratory weakness, values commonly used to identify MC [2]. Patients with MG commonly exhibit bulbar weakness prior to respiratory muscle weakness, which can predispose to respiratory failure. Signs of bulbar weakness include dysphagia, nasal or staccato speech, jaw or lingual weakness, and facial paresis. A series by Thomas et al. [3] found 3 independent risk factors for prolonged intubation (>14 days) in patients with MC, including age >50 years, VC < 25 ml/kg on post-intubation days 1 to 6, and bicarbonate >30 mmol/L. Early intubation, prevention of atelectasis, aggressive chest physiotherapy, frequent suctioning and implementation of high PEEP during mechanical ventilation are recommended in these patients [4]. Common precipitants of MC include infection, surgical stress, pregnancy, aspiration pneumonitis, and medication use including macrolide or quinolone antibiotics, antidysrhythmic agents, antipsychotics, beta blockers, calcium channel blockers, and steroids, paradoxically [4].

In light of the COVID-19 pandemic, MG patients should be encouraged to continue their current treatment regimens, but engage in extra vigilant social distancing [5]. Healthcare providers should weigh the risk of viral infection or worsening MC prior to starting a B cell depleting therapy. If a patient becomes affected by COVID-19, and is exhibiting concurrent infection or sepsis, it may be useful to halt immunosuppressive medications [5]. The combination of MG and COVID-19 represent unique and complicated challenges to health care practitioners; the implications of which should be appropriately addressed during perioperative planning.

Declaration of competing interest

The authors declare that there is no conflict of interest.