Pembrolizumab-induced autoimmune encephalitis in a patient with advanced non-small cell lung cancer: A case report

Abstract

Immune checkpoint inhibitors have markedly changed lung cancer treatment and improved overall survival. However, immune checkpoint inhibitors may be associated with various adverse events, including encephalitis, although this complication is rare. We herein describe the clinical characteristics of a case of immune checkpoint inhibitor-induced encephalitis and its management. A 51-year-old man with squamous non-small cell lung cancer was receiving pembrolizumab treatment when he suddenly displayed an altered level of consciousness. Cerebrospinal fluid examination revealed elevated lymphocyte count and autoimmune encephalitis was suspected. The patient was promptly started on steroids and his consciousness immediately improved. Pembrolizumab treatment was discontinued; however, stable disease was maintained. In conclusion, encephalitis is a rare but possibly fatal adverse event of immune checkpoint inhibitors, and prompt diagnosis and treatment are mandatory.

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

“…We searched PubMed for irEncephalitis (including meningoencephalitis, encephalomyelitis, and cerebellitis) cases and identified 60 patients (Tables 1 and S1), 22,32‐73 35 (58.3%) of which were males. The median onset age was 60 years (interquartile range, IQR: 53‐69; range: 19‐83).…”

Autoimmune Encephalitis Related to Cancer Treatment with Immune Checkpoint Inhibitors: Systematic Review

“…We divided patients in the following (partly overlapping) subgroups: With brain metastases (BM+) (N=16) 11,13,17,23,28,31,33,35,45,47,38,41,42,44,46 , without brain metastases (BM-) (N=38) 10,12,24–27,29–32,34,36,14,37,39,40,42,43,45,46,48,15,16,18–22 , with limbic AIE (N=16) 14,18,46,47,19,22,26,27,34,36,39,42 and extra-limbic AIE (N=38) 10,11,23–26,28–33,12,35,37,38,40–42,44–46,48,13,15–17,20–22 . Limbic AIE were determined according to criteria for AIE by Graus et al 7 One patient had bitemporal FLAIR lesions and anti-Ma2 antibodies present in CSF, but the clinical presentation was not consistent with involvement of the limbic system, there were no CSF pleocytosis or EEG activity suggestive of temporal involvement, and this patient was therefore labelled as having extra-limbic AIE.…”

“…Steroid treatment was initiated in 51 patients (94%), while one patient did not receive any treatment 12,13 and two patients were already on steroid treatment which was not increased. Four patients 12,31 were only treated with oral steroids, 22,35,41,47 35 patients received iv pulse therapy of which 23 were given high dose treatment (> 500mg daily), and in 12 patients (22%) steroid dosage was not disclosed. IVIG was initiated in 15 patients (28%).…”

“…Following application of the AIE criteria proposed by Graus et al, 7 23 patients 11,17,32,33,35,37,38,40,44,46,20–23,28–31 fulfilled the criteria for possible AIE; 16 patients 14,18,43,46,47,19,22,26,27,34,36,39,42 , including the one in Figure 1, criteria for limbic AIE; two patients 31,41 criteria for definite anti-NMDA AIE; two patients 10,45 criteria for probable auto-antibody negative AIE, one patient 16 criteria for Hashimoto’s encephalopathy (aka. steroid responsive encephalopathy associated with autoimmune thyroiditis, SREAT); and one patient 48 met criteria for definite acute disseminated encephalomyelitis (ADEM).…”

Pembrolizumab-associated autoimmune encephalitis in an elderly patient with advanced non-small cell lung cancer. A clinical case

“…Se realizó una búsqueda bibliográfica encontrando siete casos de encefalitis autoinmune por PEM [6][7][8][9][10][11] hasta octubre de 2020 (Tabla 1), con una edad media de 61 años (DE = 10,4); 71% varones, tres pacientes con melanoma metastásico y cuatro con CNMP. La mediana de ciclos de tratamiento acumulados a los que debutó la clínica neurotóxica fue de 8 (rango: 1-16).…”