LAUSR

We thank Drs. Filip and Jarosław for their comment questioning the need for intravenous immunoglobulin (IVIG) for all cases of post-COVID-19 myoclonus-ataxia syndrome. The response to IVIG or steroids suggests indeed an autoimmune etiology, although pathophysiology, course, and management are not fully understood yet. We have also read with interest the reported cases of ataxia-myoclonus syndrome, being one successfully treated with steroids, followed by IVIG, and the other two with steroids only. The same holds true for the additional patient, although he was not entirely similar to those we reported. In particular, complete regression in this patient occurred after 3 months, whereas after 17 days in our report; moreover, due to diabetes, we could not consider steroids. In this context, we wonder whether there would have been any effect of steroid bolus, followed by oral prednisone at 70 mg/day for 4 weeks, on hypertension, atrial fibrillation, and glycemia. We agree that not all patients may need IVIG, at least until the superiority of one treatment with respect to the other is demonstrated. A reasonable approach might be to start with the 3–5 days of IV steroids at high doses (eg, 1 g/day) in patients without comorbidities (eg, diabetes, hypertension, cardiac arrhythmia, obesity, osteoporosis, etc.) or if steroids are not contraindicated, and then shift to IVIG if no or incomplete recovery occurs within 2 weeks. In case of relevant comorbidities or contraindications to steroids, immediate treatment with IVIG should be considered. On the other hand, as the authors themselves mentioned, the systematic review of 46 papers analyzing hyperkinetic movement disorders in COVID-19 showed that, in 20 studies, IVIG were used with good response and a substantial number was treated with steroids in combination with IVIG. Moreover, in approximately 80% of cases, myoclonus improved or subsided within days-to-2 months spontaneously or after immunotherapies (ie, corticosteroids, IVIG, or plasma exchange), thus highlighting the relevance of IVIG in these patients. In our case, we could not predict the patient’s response, as well as his course, if he was treated only with steroids, instead of IVIG. Nevertheless, we would not agree on the use of prolonged high oral dose of steroids after the bolus administration, at least for two reasons: because of high risk of side effects and, as a general rule, acute monophasic autoimmune neurological diseases (such as encephalitis or acute disseminated encephalomyelitis) do not need it. In other words, either the steroid bolus is effective or it is better to shift to IVIG. Concluding, we acknowledge that, in some cases, treatment with steroids may be equally effective, cheaper, and more available than IVIG, although with high iatrogenic risks, especially in patients with comorbidities. As such, we suggest too to start with steroids and shift to IVIG in case of nonresponsiveness or contraindications, but not to prolong the steroid treatment for a month after the bolus. As recently proposed indeed, IVIG, in selected cases, may represent a safe and effective treatment for COVID-19-associated neurological manifestations.