Atezolizumab-related encephalitis in the intensive care unit: Case report and review of the literature

Abstract

Atezolizumab is a monoclonal antibody that targets programmed death ligand-1. Treatments with this drug may cause immune-related adverse events by creating an exaggerated inflammatory response. The most common side effects are fatigue, rash, and gastrointestinal symptoms. Cases of central nervous system toxicity such as encephalitis and encephalopathy are uncommon. We present the case of a 53-year-old female with metastatic squamous cell carcinoma of the cervix who presented to the emergency room 13 days after receiving atezolizumab with altered mental status, headache, and meningeal signs. She was admitted to the intensive care unit. Infectious, anatomical, and neoplastic etiologies were ruled out. Auto-immune meningoencephalitis was diagnosed and treated with high-dose steroids. Within 10 days of the diagnosis, she had clinical, radiological, and laboratory improvement. Given the increasing use of novel immunotherapies and life-threatening side effects associated with them, healthcare providers in the intensive care unit should be aware of their diagnosis and management.

Atezolizumab-associated encephalitis in metastatic lung adenocarcinoma: a case report

“…Encephalitis associated with atezolizumab has rarely been reported as an irAE; to the best of our knowledge, only three cases have been reported [4][5][6]. Encephalitis was not reported as an irAE for atezolizumab in Phases 1 and 2 of the POPLAR trial (atezolizumab vs. docetaxel for patients with previously treated non-small cell lung cancer).…”

“…Additionally, in the Impower 150 study, a randomized, phase III study (atezolizumab in combination with carboplatin plus paclitaxel with or without bevacizumab vs. carboplatin plus paclitaxel and bevacizumab), 1 of 373 patients (0.3%) developed encephalitis [8]. These patients developed encephalitis about 2 weeks after treatment with atezolizumab and showed fever and consciousness disorder, except for one who had a normal temperature [5]. CSF pleocytosis and elevated protein levels are common.…”

Neurological immune‐related adverse events associated with immune checkpoint inhibitors: A review of the literature

“…19,20 There are some overlap of symptoms between irMeningitis and irEncephalitis, and, meningitis can concur with encephalitis (meningoencephalitis). 22,32,40,72 7.4-8.3% patients with irMeningitis finally died. 19,20 Compared with irEncephalitis, the median time to death is shorter for irMeningitis (61 vs 42 days).…”

Paraneoplastic Confusion: A Case of Anti-Hu Encephalitis

“…The possibility of autoimmune encephalitis secondary to atezolizumab was also investigated; however, the patient had tolerated 11 cycles of maintenance therapy with this medication with no acute changes and the medication was discontinued about a month prior to admission. The rare encephalitis caused by atezolizumab has been reported to occur days after initiation of treatment, and it has been seen more frequently in patients with non-SCLC [16,17]. Given the history of the SCLC, which is frequently associated with paraneoplastic syndromes, the clinical rationale moved towards the exploration of paraneoplastic encephalitis.…”