Neurology of COVID-19 in Singapore

Abstract

Purpose: To describe the spectrum of COVID-19 neurology in Singapore.

Method: We prospectively studied all microbiologically-confirmed COVID-19 patients in Singapore, who were referred for any neurological complaint within three months of COVID-19 onset. Neurological diagnoses and relationship to COVID-19 was made by consensus guided by contemporaneous literature, refined using recent case definitions.

Results: 47,572 patients (median age 34 years, 98% males) were diagnosed with COVID-19 in Singapore between 19 March to 19 July 2020. We identified 90 patients (median age 38, 98.9% males) with neurological disorders; 39 with varying certainty of relationship to COVID-19 categorised as: i) Central nervous system syndromes-4 acute disseminated encephalomyelitis (ADEM) and encephalitis, ii) Cerebrovascular disorders-19 acute ischaemic stroke and transient ischaemic attack (AIS/TIA), 4 cerebral venous thrombosis (CVT), 2 intracerebral haemorrhage, iii) Peripheral nervous system-7 mono/polyneuropathies, and a novel group, iv) Autonomic nervous system-4 limited dysautonomic syndromes. Fifty-one other patients had pre/co-existent neurological conditions unrelated to COVID-19. Encephalitis/ADEM is delayed, occurring in critical COVID-19, while CVT and dysautonomia occurred relatively early, and largely in mild infections. AIS/TIA was variable in onset, occurring in patients with differing COVID-19 severity; remarkably 63.2% were asymptomatic. CVT was more frequent than expected and occurred in mild/asymptomatic patients. There were no neurological complications in all 81 paediatric COVID-19 cases.

Conclusion: COVID-19 neurology has a wide spectrum of dysimmune-thrombotic disorders. We encountered relatively few neurological complications, probably because our outbreak involved largely young men with mild/asymptomatic COVID-19. It is also widely perceived that the pandemic did not unduly affect the Singapore healthcare system.

Keywords: COVID-19; Coronavirus; Neurological manifestations; Pandemic; SARS-CoV-2.

Graphical abstract

Fig. 1

Neuroimaging in 3 patients with COVID-19 associated central nervous system (CNS) syndromes. Case 1 – Probable acute disseminated encephalomyelitis (A-D): Axial T2-weighted brain MRI (A) showing discrete hyperintense foci in the deep and subcortical white matter. Axial diffusion weighted imaging (DWI) (B) and apparent diffusion coefficient (ADC) (C) images demonstrating DWI hyperintensity of the lesions without restricted diffusion on ADC maps. Sagittal T2-weighted image of the cervical spine (D) showing a small linear lesion on the right side of the spinal cord at C1 (white arrow). Case 2 – Possible encephalitis (E-H): Axial T2-weighted images showing (E) bilateral curvilinear high signal paralleling the ventricles and (F) in the inferior frontal white matter (white arrows). Corresponding axial T1-weighted image (G) demonstrating low signal in the white matter lesions (white arrows). Axial T2-weighted image (H) revealing discrete hyperintense lesions in the deep white matter on background of diffuse leukoencephalopathy. Case 3 – Possible encephalitis (I): Axial T2-weighted MRI (I) showing T2W hyperintensity in the right frontal and parietal deep and subcortical white matter; and an evolving infarct in the left frontal and parietal lobes.