SHM Converge Scientific Abstract ePoster Gallery-Immune Checkpoint Inhibitor Encephalitis Mimicking Infectious Meningoencephalitis

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This case describes a 49-year-old woman with metastatic melanoma to the brain who was treated with surgery, radiation, and immunotherapy including nivolumab and ipilimumab. She presented with vomiting, fatigue, lethargy, dysuria, abdominal pain, and staring spells, and was initially admitted for presumed sepsis from acute cystitis because she was febrile and tachycardic. After admission, she developed worsening confusion, speech changes, lethargy, fluctuating orientation, headache, neck pain, and a bilateral erythematous macular rash. She also became hemodynamically unstable and required pressors.<br /><br />Because of concern for meningitis or encephalitis, she was treated empirically with broad-spectrum antimicrobials and acyclovir. However, imaging showed no acute new brain process, EEG showed no seizures, and lumbar puncture revealed mild lymphocytic pleocytosis with elevated protein and glucose. CSF, blood, and urine cultures were negative, as were meningitis/encephalitis testing and GI infectious studies. With no infectious source identified, clinicians suspected an immune-related neurologic adverse event from checkpoint inhibitor therapy and started methylprednisolone.<br /><br />Her fever, leukopenia, hemodynamic instability, and neurologic symptoms improved rapidly after steroids. She was diagnosed with immune checkpoint inhibitor encephalitis, based on subacute mental status changes, CSF inflammation, and exclusion of alternative causes. She was discharged on a steroid taper and did not relapse.<br /><br />The report emphasizes that immune checkpoint inhibitors can cause serious infection mimics, including encephalitis, and that prompt recognition is essential because the condition can be fatal. Steroid responsiveness and inflammatory CSF findings may support the diagnosis.

Asset Subtitle

Katarzyna M. Purzycka

Meta Tag

Author List Brian Petroelje MD, Hannah Bray, Katarzyna M. Purzycka, Kevin FitzGerald

Category Clinical Vignettes

Concept Immune Checkpoint Inhibitor

Concept Immune-Related Adverse Event

Concept Encephalitis

Concept Glucocorticoid Therapy

Concept Altered Mental Status

Distinguished Non-Finalist

Presenter Organization Corewell Health West

Presenting Author Katarzyna M. Purzycka

Track Adult

Keywords

metastatic melanoma

brain metastasis

nivolumab

ipilimumab

immune checkpoint inhibitor encephalitis

confusion

cerebrospinal fluid pleocytosis

methylprednisolone

steroid responsive

infection mimic

Immune Checkpoint Inhibitor

Immune-Related Adverse Event

Encephalitis

Glucocorticoid Therapy

Altered Mental Status