Kamikawa Kohei, Takada Ryohei, Honda Yuya, Goto Harue, Okada Takashi
Department of Psychiatry, Nara Prefecture General Medical Centre, Nara, Japan.
Department of Psychiatry, Nara Medical University School of Medicine, Kashihara, Japan.
Neuropsychopharmacol Rep. 2025 Sep;45(3):e70044. doi: 10.1002/npr2.70044.
Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, a type of autoimmune encephalitis, characterized by acute onset neuropsychiatric symptoms, predominantly affects young females and is often associated with ovarian teratomas. Although small cell lung cancer (SCLC) is a known cause of paraneoplastic encephalitis, its association with anti-NMDAR encephalitis is rare and often carries a poor prognosis due to limited response to immunotherapy.
An 80-year-old male with no psychiatric history presented with flu-like symptoms, followed by the acute onset of neuropsychiatric symptoms, including pressured speech, agitation, memory impairment, and abnormal behavior. Autoimmune encephalitis was suspected due to mildly elevated cerebrospinal fluid (CSF) white cell count and a mass in the right upper lung detected by whole-body computed tomography (CT) on the first day of hospitalization. High-dose intravenous corticosteroids were administered on Day 1, resulting in prompt and sustained improvement in symptoms. CSF was later confirmed positive for anti-NMDAR antibodies, and a bronchoscopy biopsy of the pulmonary mass diagnosed SCLC. The patient recovered without neurological deficits and was discharged in stable condition on hospital Day 30.
This was a rare case of anti-NMDAR encephalitis associated with SCLC in an elderly male patient. Diagnosis in elderly individuals is often challenging because of the atypical presentations and lower tumor association. Nevertheless, timely intervention initiation may lead to favorable outcomes. Clinicians should consider autoimmune encephalitis, including anti-NMDAR encephalitis, when evaluating acute onset neuropsychiatric symptoms in elderly individuals and initiate early immunotherapy alongside tumor screening.
抗N-甲基-D-天冬氨酸受体（NMDAR）脑炎是一种自身免疫性脑炎，以急性起病的神经精神症状为特征，主要影响年轻女性，常与卵巢畸胎瘤相关。虽然小细胞肺癌（SCLC）是副肿瘤性脑炎的已知病因，但其与抗NMDAR脑炎的关联罕见，且由于对免疫治疗反应有限，预后往往较差。
一名80岁无精神病史男性患者，最初出现类似流感症状，随后急性起病出现神经精神症状，包括言语增多、烦躁不安、记忆障碍和行为异常。住院第一天，由于脑脊液（CSF）白细胞计数轻度升高以及全身计算机断层扫描（CT）发现右上肺有肿块，怀疑为自身免疫性脑炎。第1天给予大剂量静脉注射皮质类固醇，症状迅速且持续改善。脑脊液后来被证实抗NMDAR抗体阳性，肺部肿块的支气管镜活检诊断为小细胞肺癌。患者康复，无神经功能缺损，于住院第30天病情稳定出院。
这是一例老年男性患者中罕见的与小细胞肺癌相关的抗NMDAR脑炎病例。由于临床表现不典型且肿瘤相关性较低，老年患者的诊断往往具有挑战性。然而，及时开始干预可能会带来良好的结果。临床医生在评估老年患者急性起病的神经精神症状时应考虑自身免疫性脑炎，包括抗NMDAR脑炎，并在进行肿瘤筛查的同时尽早开始免疫治疗。
