SHM Converge Scientific Abstract ePoster Gallery-A Case of Influenza Associated Encephalitis

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This case describes a 29-year-old woman with hypothyroidism and rheumatoid arthritis who developed acute confusion, agitation, paranoia, and bizarre behavior after influenza-like illness during travel. She also had headache, chills, myalgias, cough, sinus pressure, and malaise, and a home test was positive for influenza. On examination she was restless, confused, and unable to communicate effectively, though she remained alert. Initial labs, chest X-ray, and head CT were normal.<br /><br />Brain MRI revealed two non-enhancing hyperintense lesions in the cerebral white matter. Cerebrospinal fluid showed normal glucose, low-normal protein, and minimal cells, with negative testing for multiple infectious and autoimmune causes, including HSV, VZV, SARS-CoV-2, Dengue, HIV, and encephalitis/autoimmune panels. A nasal swab was positive for influenza A, while CSF influenza testing was not performed.<br /><br />She was treated with oseltamivir and supportive care, leading to marked improvement. She was discharged in stable condition with complete resolution of encephalopathy and later returned to her usual activities.<br /><br />The most likely diagnosis was influenza-associated encephalitis (IAE), a rare but important cause of encephalopathy in adults. The report emphasizes that adult IAE often lacks a distinct clinical presentation and may present with confusion and seizures, sometimes with headache or agitation. MRI findings are variable, and abnormalities may indicate worse prognosis. Treatment commonly includes oseltamivir, though its benefit is uncertain because influenza-related brain dysfunction may involve direct infection or a post-infectious autoimmune process, and oseltamivir has limited CNS penetration. This case highlights the importance of considering influenza in the differential diagnosis of unexplained encephalopathy.

Asset Subtitle

Kyle James

Meta Tag

Author List Anna Patkowska, Elio Ragheb, Kyle James, Robert Parker, Willie Smith Jr.

Category Clinical Vignettes

Concept Influenza-associated encephalitis

Concept Acute Confusion

Concept Encephalopathy

Concept Agitation

Concept Influenza-like illness

Distinguished Non-Finalist

Presenter Organization Emory University Hospital Midtown

Presenting Author Kyle James

Track Adult

Keywords

influenza-associated encephalitis

encephalopathy

acute confusion

influenza A

brain MRI lesions

cerebrospinal fluid

oseltamivir

adult encephalitis

paranoia

neurological complications

Influenza-associated encephalitis

Acute Confusion

Encephalopathy

Agitation

Influenza-like illness