Trismus caused by paraneoplastic brainstem encephalitis

Abstract

We discuss the assessment and differential diagnoses of a middle-aged man who presented with trismus, double vision and behavioural problems. MRI scan of the brain was initially normal, but a month later showed high signal in the hippocampal region on fluid attenuated inversion recovery sequence (FLAIR) imaging. We suspected a paraneoplastic brainstem encephalitis because of his smoking history, rapidly progressive symptoms and abnormal brainstem signs. A positron emission tomography-CT scan identified abnormal subcarinal nodes, shown on biopsy to be metastatic small cell lung cancer. He is currently undergoing treatment with chemotherapy and radiotherapy.

Trismus as the Initial Presentation of Anti-Hu Paraneoplastic Neurological Syndrome

“…4 Notably, only a single case has been reported of a patient with small cell lung cancer and anti-Hu positivity presenting with trismus and horizontal conjugate gaze palsy. 5 The primary treatment strategies for anti-Hu PNS include the identification and treatment of tumors, particularly small cell lung cancer. Limited evidence exists on the use of immunotherapy in patients with anti-Hu PNS.…”

“…4 Notably, only a single case has been reported of a patient with small cell lung cancer and anti-Hu positivity presenting with trismus and horizontal conjugate gaze palsy. 5…”