Cognitive-Behavioral Syndrome, a diagnostic challenge in NMOSD. The Arch Bridge Pattern can Help.

Clinical case:

A 59 years old female patient started, in July 2022, a vertiginous syndrome with an asymmetric and bilateral involvement. Six months later, she had a bitemporal painless visual disability that developed few days after taking the fourth dose of covid vaccine. In August 2023 she developed a rapidly progressive dementia with impairment of memory, praxis and visuospatial orientation, without hallucinations or behavioral changes.

On MRI, T2/FLAIR revealed hypersignal surrounding the posterior horns of the lateral ventricles, affecting the splenium of the corpus callosum (arch bridge pattern). Indirect immunofluorescence showed aquaporin-4 antibody positive (1:80) by TBA method.

Discussion:

NMOSD is a disease that was better elucidated with the discovery of the anti-aquaporin-4 antibody due to its high sensitivity (around 80%) and even higher specificity (99%). The delay diagnostic due non-hospitalization or investigation of a pons syndrome (rare presentation in NMO) and consequently non-treatment, allowed the occurrence of an even rarer syndrome, a cognitive condition associated with corpus callosum injury (the arch bridge pattern). This sign (described in our patient) is a typically involved at its a ependymal surface, with the involvement often affecting most of its length, in acute phases, edematous and heterogeneous hyperintensity on FLAIR / T2 weighted images is usually observed, assuming a typical marbled. Corpus callosum injuries are present in 18% of all patients, but the arch sign is much rare.

Final Comments:

This clinical case leads us to reflect on the urgency for neuroimmunology patients to reach reference hospitals, to promptly receive adequate diagnosis and treatment, as well as to explain rare presentations in patients with (NMO: pons and corpus callosum), and finally leads us to increasingly testing anti-aquaporin-4 in cases that have not yet been elucidated