SHM Converge Scientific Abstract ePoster Gallery-Altered Mental Status With Seizures: A Case of Paraneoplastic Encephalitis

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This case describes a 65-year-old woman with focal epilepsy, carotid stenosis, and a recent endarterectomy who developed four weeks of sudden aphasia, right-sided weakness, and worsening altered mental status. She was found to have multiple subclinical seizures, and initial symptoms were partly attributed to possible cerebral hyperperfusion syndrome after surgery. However, imaging suggested malignancy, and biopsy confirmed small cell lung carcinoma (SCLC). Autoimmune testing was positive for anti-Hu (anti-ANNA-1) and anti-P/Q type calcium channel antibodies, supporting a diagnosis of paraneoplastic encephalitis.<br /><br />During hospitalization, she was treated with high-dose steroids (1 g solumedrol) and plasmapheresis/apheresis, which led to reduced seizure activity and improved alertness. Over the broader course, she also required seizure medication adjustments during two admissions. After the SCLC diagnosis, she completed four cycles of carboplatin and etoposide plus mediastinal radiation. At follow-up, autoimmune-directed therapy included glucocorticoids and rituximab.<br /><br />The abstract highlights that anti-Hu antibodies are typically T-cell mediated and strongly associated with malignancy, especially SCLC, while anti-P/Q antibodies are linked to antibody-mediated Lambert-Eaton myasthenic syndrome and also often occur with SCLC. Paraneoplastic syndromes occur in about 9% of SCLC cases and commonly present with subacute memory changes, psychiatric symptoms, or seizures.<br /><br />Key points are that paraneoplastic encephalitis should remain on the differential diagnosis in patients with new neurologic symptoms and seizures, diagnosis relies on imaging, serology/CSF, and EEG, and treatment focuses on controlling the underlying cancer plus immunotherapy. The authors conclude that plasmapheresis may provide additional benefit alongside corticosteroids and IVIG, though complete recovery is uncommon.

Asset Subtitle

Michael A. Durda

Meta Tag

Author List Allison Heacock, Michael A. Durda, Philip Huang

Category Clinical Vignettes

Concept Paraneoplastic Encephalitis

Concept Small Cell Lung Carcinoma

Concept Treatment of Malignancy

Concept Altered Mental Status

Concept Seizure

Distinguished Non-Finalist

Presenter Organization The Ohio State University Wexner Medical Center

Presenting Author Michael A. Durda

Track Adult

Keywords

paraneoplastic encephalitis

small cell lung carcinoma

anti-Hu antibodies

anti-P/Q calcium channel antibodies

focal epilepsy

subclinical seizures

plasmapheresis

high-dose steroids

carotid endarterectomy

autoimmune neurology

Paraneoplastic Encephalitis

Small Cell Lung Carcinoma

Treatment of Malignancy

Altered Mental Status

Seizure