Abstract Background 30 year-old female with medical history of non-small cell lung carcinoma (NSCLC) with previous metastasis to the brain that had been on Tagrisso with reported disease remission who presented with several weeks of ascending muscle weakness and spasm leading to intubation. Case Presentation The patient was admitted to the hospital for ascending muscle weakness on hospitalist service. Initial imaging (MRI brain, C/T/L-spine) ruled out metastatic or compressive lesions but revealed possible cauda equina involvement. Lumbar puncture (LP) with elevated opening pressure and CSF studies, including paraneoplastic panel, showed no malignancy. She was treated empirically with IVIG and methylprednisolone for suspected paraneoplastic syndrome (PNS), leading to partial improvement but complicated by steroid-induced encephalopathy. Neurology/oncology diagnosed probable Stiff Person Syndrome (SPS); diazepam was initiated and patient underwent five sessions of PLEX without improvement. Her course was further complicated by hypoxemia, tachypnea, and hypotension requiring high-flow oxygen and vasopressors. She progressively weakened and was intubated for acute hypoxic respiratory failure (AHRF). After intubation she underwent another LP which was again negative. Repeat MRI imaging showed leptomeningeal signal enhancement vs artifact of the lumbar spine. Imaging showed stable loculated pleural effusion and evolving pulmonary nodules concerning for NSCLC progression. Transbronchial biopsy was attempted however space was blood-filled. The patient underwent peripheral electromyography (EMG) which was negative. Given high suspicion of leptomeningeal disease (LMD), the patient underwent a third LP which was positive for malignant cells. A goals of care discussion was had with the patient and her husband, and the decision was made to pursue comfort care instead of aggressive treatment of her NSCLC. Outcome and Management: This patient elected to pursue comfort care and died in the hospital. Had she wanted treatment then craniospinal irradiation, systemic chemotherapy including Amivantimab / Lazertinib, and IT chemotherapy would have been pursued. Discussion This was a complex patient presentation of ascending muscle weakness and spasms who was ultimately found to have NSCLC disease progression to the leptomeningeal system. She underwent extensive workup given broad differential of inflammatory vs medication induced neuropathy vs concomitant malignancy vs paraneoplastic myelopathy vs SPS vs leptomeningeal disease. Neuromuscular weakness is a rare but important cause of AHRF. This case explores the broad differential and workup for neuromuscular weakness as a cause of AHRF and highlights the importance of a high clinical suspicion for LMD as it has a high rate of false-negative work-up and requires high-risk treatment protocols. This abstract is funded by: None
Hunting et al. (Fri,) studied this question.