Critical illness neuropathy in severe COVID-19: a case series

Neurological complications of SARS-CoV-2 disease have received growing attention, but only few studies have described to date clinical and neurophysiological findings in COVID patients during their stay in intensive care units (ICUs). Here, we neurophysiologically assessed the presence of either critical illness neuropathy (CIP) or myopathy (CIM) in ICU patients.

Patients underwent a neurophysiological assessment, including bilateral examination of the median, ulnar, deep peroneal and tibial motor nerves and of the median, ulnar, radial and sural sensory nerves. Needle electromyography (EMG) was performed for both distal and proximal muscles of the lower and upper limbs. In order to differentiate CIP from CIM, Direct Muscle Stimulation (DMS) was applied either to the deltoid or tibialis anterior muscles. Peak to peak amplitudes and onset latencies of the responses evoked by DMS (DMS_amp, DMS_lat) or by motor nerve stimulation (MNS_amp, MNS_lat) were compared. The ratio MNS_amp to DMS_amp (NMR) and the MNS_lat to DMS_lat difference (NMD: MNS_lat - DMS_lat) were also evaluated.

Nerve conduction studies showed a sensory-motor polyneuropathy with axonal neurogenic pattern, as confirmed by needle EMG. Both MNS_amp and NMR were significantly reduced when compared to controls (p < 0.0001), whereas MNS_lat and NMD were markedly increased (p = 0.0049).

We have described COVID patients in the ICU with critical illness neuropathy (CIP). COVID-related CIP could have implications for the functional recovery and rehabilitation strategies.