Nivolumab-induced posterior reversible encephalopathy syndrome

A 47-year-old woman with metastatic, poorly differentiated lung cancer with neuroendocrine features was brought to the hospital after 4 days of nausea, vomiting, disorientation, and 1 generalized tonic clonic seizure. On examination, her blood pressure was 148/95 mm Hg, heart rate 95 bpm, and temperature 36.4°C. She was encephalopathic and had cortical blindness. She had no history of seizures or visual impairment. MRI brain without contrast showed changes consistent with posterior reversible encephalopathy syndrome (PRES; figure, A). She had been on nivolumab, of which she had received 2 doses; the last dose was 24 days before the onset of this illness. She had not received any other cancer-directed therapy for 6 months. She did not have any other cause of PRES (pregnancy, severe hypertension, sepsis). The patient was treated with supportive therapy and returned to baseline mental state and vision after a few weeks. However, she developed a seizure disorder with a focal onset in the form of stereotyped visual hallucinations of primary colors in a geometrical arrangement and secondary generalization. Repeat MRI with contrast 3 and 9 months later showed incomplete resolution of PRES lesions, with residual cortical/subcortical nonenhancing gliosis seen in bilateral occipital poles and left frontotemporal area (figure, B).