Fever, Cognitive Decline, and Multifocal T2 Hyperintensities on Brain MRI: A Case Report of Cytokine Release Syndrome.

Cytokine release syndrome (CRS) is a systemic inflammatory response characterized by fever, constitutional symptoms, and multiorgan dysfunction. While most commonly associated with immunotherapy, CRS can also be incited by infections or drugs. This case details the presentation and evaluation of a 71-year-old woman with a history of primary myelofibrosis and breast cancer who presented with acute onset of altered mental status. Initial vital signs were notable for severe hypertension, tachycardia, and fever. The patient was alert and oriented only to self, with little verbal output, and spontaneously moving all extremities. The patient had a submandibular gland abscess that had been diagnosed prior to presentation via a computed tomography scan of the neck. A comprehensive analysis, including blood tests, cerebrospinal fluid (CSF) analysis, electroencephalogram (EEG), and neuroimaging, was performed. Severe leukocytosis was noted and brain MRI demonstrated scattered areas of diffusion restriction and diffuse T2 white matter hyperintensities. Serial imaging demonstrated the progression of T2 hyperintensities. Ultimately, CRS was the most likely diagnosis. In this case, the inciting event was likely an infectious etiology, suspected to be the submandibular gland abscess that was present at the time of admission. It is vital to have a high index of suspicion for CRS in patients with recent infection, drug exposure, or immune dysregulation.