PD-1/PD-L1 checkpoint inhibitor-induced encephalitis in patients with lung adenocarcinoma: a report of three cases

Immune checkpoint inhibitor (ICI)-induced encephalitis is rare. We present three cases of encephalitis associated with ICIs in lung adenocarcinoma patients. These patients presented with a variety of symptoms, but one of the common symptoms for all patients was loss of consciousness. All patients responded well to steroid treatment and survived longer than one month after the onset of symptoms. These cases highlight the difficulties in diagnosing encephalitis based only on clinical information, and timely management is important to improve survival. Opportunistic infections also have to be ruled out to diagnose ICI-induced encephalitis especially when brain metastases co-exist.