Recurrent Transient Neurologic Symptoms Mimicking Seizures in a Patient with Plateau Waves due to Leptomeningeal Carcinomatosis
Abstract number :
2.153
Submission category :
18. Case Studies
Year :
2025
Submission ID :
260
Source :
www.aesnet.org
Presentation date :
12/7/2025 12:00:00 AM
Published date :
Authors :
Presenting Author: Lindy Smith, DO – University of Chicago
Ashley Raedy, DO – University of Chicago
Shasha Wu, MD, PhD – University of Chicago
Kaitlin Seibert, MD – University of Chicago
Tracey Fan, DO – University of Chicago
Rationale: Clinical and electroencephalographic features of plateau waves—paroxysmal increases in intracranial pressure (ICP) that lead to transient decreases in cerebral perfusion pressure and neurologic deficits—remain incompletely characterized. These events are often misinterpreted as seizures. We describe a case of recurrent, stereotyped episodes of altered mental status and focal neurologic deficits, accompanied by autonomic symptoms, attributable to plateau waves in the context of leptomeningeal carcinomatosis (LMC).
Methods: We conducted a retrospective chart review of clinical events, imaging, and video electroencephalography (EEG) in a 43-year-old female with stage IV breast cancer and known osseous metastases, newly diagnosed with LMC. She presented with several weeks of generalized weakness and headaches.
Results: Over the hospitalization the patient experienced multiple recurrent episodes characterized by sudden onset of unresponsiveness, anisocoria, fluctuating heart rate, irregular breathing, and hypertension. Some events also included left-sided shaking or gaze deviation. Episodes occurred frequently—up to 11 times in one day—and typically lasted 5–15 minutes, with spontaneous return to baseline between events. At least one episode was triggered by a positional change. Video EEG captured abrupt onset of diffuse delta slowing followed by attenuation of background activity, without epileptiform discharges. Antiseizure medications (Keppra and Vimpat) were initiated and titrated without clinical improvement. Brain MRI with and without contrast revealed new leptomeningeal metastases without parenchymal lesions. Lumbar puncture (LP) showed normal opening pressure (15 cm H₂O), glucose 25 mg/dL, protein 209 mg/dL, and no leukocytosis. A repeat LP was declined due to goals of care. Despite a normal opening pressure, EEG findings raised concern for transient ICP elevations. The patient improved with hyperventilation and head-of-bed elevation. Acetazolamide was subsequently initiated, resulting in improved mentation and reduced episode frequency. Recognition of plateau waves led to significant changes in management, including minimization of unnecessary antiseizure medications and timely initiation of radiation therapy.
Conclusions: This case highlights the diagnostic challenge of distinguishing seizures from plateau waves in patients with leptomeningeal carcinomatosis. While direct ICP monitoring may be unavailable, EEG findings—specifically abrupt delta slowing without epileptiform activity that correlates with clinical symptoms—can provide valuable diagnostic insight and guide appropriate treatment decisions.
Gold CA, Odom N, Srinivasan S, et al. Electrographic correlates of plateau waves in patients with leptomeningeal metastases. Neurohospitalist. 2016;6(4):161-166. doi:10.1177/1941874416648194.
Funding: No funding was recieved in support of this case report.
Case Studies