Objective:

Not applicable

Background:

Cytotoxic lesions of the corpus callosum (CLOCC) is a rare condition associated with transient lesions in the splenium of the corpus callosum identified on MRI. Lesions are usually associated with systemic disease including neoplastic, traumatic, vascular, and infectious entities, but most commonly type-A influenza. The pathophysiology is not fully understood, but the cytotoxic edema results as cell-cytokine interactions trigger water influx into neurons. We report an extremely rare case of CLOCC precipitated by type-B influenza. 

Design/Methods:

Not applicable

Results:

A 26-year-old woman who was recently diagnosed with Influenza B presented with headache, fever, blurry vision, and vision loss for one week. Fundoscopic examination revealed right optic disc edema. Brain MRI with/without gadolinium demonstrated hyperintensity in the splenium of the corpus callosum on FLAIR sequencing, with restricted diffusion on diffusion-weighted imaging. Dilated fundoscopic examination revealed cotton-wool-spots in bilateral retina. Lumbar puncture revealed opening pressure of 22 cm H2O and a mild lymphocytic predominant pleocytosis (13 cmm/thou) with normal CSF glucose/protein, suggesting viral etiology. CSF studies including infectious, demyelinating, and autoimmune panels were unremarkable. She was ultimately diagnosed with retinopathy and CLOCC secondary to Influenza B and discharged. Patient was found to have symptomatic improvement on subsequent follow-up with neuro-ophthalmology, and repeat MRI showing resolution of the lesion.  

Conclusions:

The incidence rate of transient splenial lesions in the setting of infections is very low, usually associated with Influenza A in the pediatric population or COVID-19 infections in the ill patients. Although few cases of Influenza A CLOCC have been reported in literature mostly in children, we report a first-time case of CLOCC following Influenza B infection in an adult. We aim to highlight the importance of early imaging in searching for causes of nonspecific neurological symptoms in patients with Influenza infections as prognosis of this condition is favorable with conservative management.