2450 ‘Cloud-like enhancement’ on MRI seen in COVID-19 related acute disseminated encephalomyelitis

Objectives With the COVID-19 pandemic, there has been increasing recognition of post-COVID-19 acute disseminated encephalomyelitis (ADEM).¹

Method We describe an ADEM case following infection with COVID-19 with atypical radiology findings of ‘cloud-like enhancement’ (multiple patchy enhancing lesions with poorly defined margins), a feature previously thought specific for neuromyelitis optica spectrum disorders (NMOSD).^{2 3}

Results A fifty year-old female presented with confusion, right hemisensory numbness and hemiparesis with gait unsteadiness in the context of a mildly symptomatic COVID-19 infection ten days prior. Her background was significant for urticaria treated with three-weekly omalizumab and depression. Magnetic resonance imaging (MRI) revealed multifocal inflammatory changes with some diffusion restriction and ‘cloud-like enhancement’. MRI whole spine showed no areas of demyelination. Cerebrospinal fluid was acellular with borderline elevated protein, negative culture and negative multiplex PCR. Antibodies against aquaporin-4 and myelin oligodendrocyte glycoprotein were negative. She was diagnosed with post-COVID-19 ADEM and was administered pulse methylprednisolone for five days followed by weaning high dose oral prednisolone and maintenance intravenous immunoglobulin (IVIg). Progress MRI demonstrated ongoing inflammatory changes and so an FDG-PET scan was performed which demonstrated no suspicious FDG avid malignancy. Two months later her clinical symptoms had largely resolved, with marked improvement in her cognitive function.

Conclusion In contrast to other reported cases of post-COVID-19 ADEM, our patient had mild antecedent infection, was relatively young and had an excellent neurologic outcome. Furthermore, ‘cloud-like enhancement’ was seen on neuroimaging, a finding previously thought specific to NMOSD.

References

1. Manzano GS, McEntire CRS, Martinez-Lage M, Mateen FJ, Hutto SK. Acute disseminated encephalomyelitis and acute haemorrhagic leukoencephalitis following COVID-19: systematic review and meta-synthesis. Neurol-Neuroimmunol, 2021;8(6):1–11.

2. Ito S, Mori M, Makino T, Hayakawa S, Kuwabara S. ‘Cloud-like enhancement’ is a magnetic resonance imaging abnormality specific to neuromyelitis optica. Ann Neurol, 2009;66(3):425–8.

3. Dutra BG, da Rocha AJ, Nunes RH, Maia Junior ACM. Neuromyelitis optica spectrum disorders: spectrum of MR imaging findings and their differential diagnosis. Radiographics, 2018;38(1):169–194.