Diaphragmatic myoclonus due to SARS-CoV-2 infection

Abstract

A wide range of neurological signs and symptoms have been associated with SARS-CoV-2 infection. In the present report, we described two Italian patients diagnosed with diaphragmatic myoclonus after COVID-19. In both cases, mild lymphocytosis at cerebrospinal fluid analysis and no structural brain changes were reported. The pathophysiological origin of the myoclonus in the two cases was different. In case 1, electroencephalogram did not reveal any cortical correlates and brain imaging of the spine was unremarkable, while in case 2, cortical origin of myoclonus was demonstrated. With the present two cases, we confirm and extend the neurological manifestations of SARS-CoV-2 infection.

Keywords: COVID-19; Diaphragmatic; Myoclonus; Neurology; SARS-CoV-2.

Fig. 1

Surface recording of left and right hemidiaphragms in case 1. A Patient at rest, ECG artifact. B Deep inspiration. C Three-hertz rhythmic synchronous discharges during involuntary contraction of abdominal muscles. Electrophysiological study of the phrenic nerve was performed by placing one monopolar needle (active electrode) two fingerbreadths above the xiphoid process and two monopolar needles (reference electrodes) over the anterior costal margin 16 cm from the active electrode. The same electrodes were used to derive electromyography activity of the diaphragm. L, left; R, right

Fig. 2

Baseline (A) and follow-up (B) electroencephalogram (EEG) recording with surface electromyography (EMG) recording of case 2. A Baseline EEG showing lateralized periodic discharges (diffuse spike and spike-and-slow-wave complexes at 2–3 Hz and 100–150 μV of amplitude) synchronous and asynchronous with diaphragm myoclonic jerks shown in surface EMG recording. B Follow-up EEG after levetiracetam 1000 mg twice daily showing diffuse spike and spike-wave complexes with a clear change in amplitude (up to 90 μV) and frequency (1–2 Hz). No myoclonic jerk at diaphragm has been detected as shown in the surface EMG recording. EOG, electro-oculogram; EMG1, right hemidiaphragm electrode; EMG2, left hemidiaphragm electrode