Opsoclonus-Myoclonus- Ataxia Syndrome (OMAS) Associated with SARS-CoV-2 Infection: Post-Infectious Neurological Complication with Benign Prognosis

Coronavirus infection primarily affects the respiratory system, also spreading from the respiratory tract to the central nervous system (CNS) [1]. CNS manifestations include febrile seizures, convulsions, altered mental status, and encephalitis [2]. Although various papers have been published describing the neuroinvasive potential of SARS-CoV-2 [3, 4], the capacity of SARS-CoV-2 to infect the CNS in humans is not well characterized, and further research regarding its unknown CNS pathology is required.

The novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) is the cause of the COVID-19 pandemic [5]. SARS-Cov-2 demonstrates partial resemblance to SARS-CoV and MERS-CoV in phylogenetic analysis, clinical manifestations, and pathological findings [6, 7]. Reports emerging from China have described ataxia as a neurological symptom of the SARS-CoV-2 infection [5]. Opsoclonus consists of back-to-back, multidirectional, conjugate saccades without an inter-saccadic interval [8]. Myoclonus is defined as a sudden, brief, “shock-like”, nonepileptic involuntary movement [9], which has been described as a symptom of SARS-CoV-2 infection [10].

Opsoclonus-Myoclonus-Ataxia syndrome (OMAS) associated COVID-19 infection has been reported recently [11, 12].

A 32 year-old man presented with cough, fever, weakness, and loss of appetite. He denied changes in smell or taste. His father had similar symptoms 5 days earlier and both tested positive for SARS-CoV-2. He developed increasing fatigue and dyspnea but denied wheezing or chest tightness. He had watery, non-bloody diarrhea throughout the febrile period until his cough improved, and he became afebrile 11 days after diagnosis. On day 12 the patient developed ataxia and myoclonus. While hospitalized on days 17 to 20, evaluation revealed a chest x-ray consistent with viral pneumonia and a normal brain MRI. IgG antibodies were positive in serum. A lumbar puncture was not performed. Opsoclonus, myoclonus, and ataxia (Videos 1 and 2) caused the inability to ambulate without assistance. Treatment with clonazepam (1mg three times per day), divalproex (1,000 mg three times per day), and oral methylprednisolone (40 mg daily) were effective, allowing the patient to walk short distances without assistance. He had mild ataxia and minimal residual myoclonus at rest. Telehealth follow-up on day 24 demonstrated substantial improvement of gait and balance (Video 3). No opsoclonus was observed, and he demonstrated very mild ataxia and occasional myoclonus.

The etiology of Opsoclonus-Myoclonus-Ataxia syndrome includes paraneoplastic, parainfectious, toxic-metabolic, and idiopathic causes [8]. Infectious causes of this syndrome have been reported with herpes virus, arbovirus, and several parasitic infections [13, 14, 15]. This is a case of OMAS secondary to SARS-CoV-2 infection, and its clinical presentation suggests a post-infectious mechanism that is possibly antibody-mediated.