Bizarre Behaviors: Autoimmune Encephalitis Masquerading as a Psychiatric Syndrome

Abstract

INTRODUCTION: N-methyl-D-aspartate (NMDA) receptor antibody encephalitis, a type of autoimmune encephalitis, first described in 2007, is predominant in females with female to male ratio of 8:2 and about 37% patients being younger than 18 years at presentation. [1,2] It is considered a part of paraneoplastic syndrome, as more than half of the cases have an underlying malignancy, ovarian teratoma being the most common. [3,4] CASE PRESENTATION: A 20 year old male with asthma was brought into the Emergency Department for seizures. He checked himself into a behavioral health facility for bizarre behavior. He received chlorpromazine, causing generalized tonic clonic seizure. He received Lorazepam and Levetiracetam. Continuous electroencephalogram showed no further seizure activity and CT head was non-diagnostic for any structural abnormalities. He was afebrile and tachycardic on examination, along with him being, initially unrousable to verbal as well as tactile stimuli. Eventually he developed more aggressive mannerism, requiring 4 point tough restraints. Not being controlled with lorazepam and haloperidol, a Dexmedotomide drip was started.Laboratory data including urine drug screen was unremarkable except elevated CK (3127 U/L). MRI Brain and lumbar puncture revealed no acute abnormality. Meningitis panel consisting of E.coli, H.influenzae, Listeria monocytogene, N. meningitidis, Strep pneumoniae and agalactiae, Cytomegalovirus, Herpes simplex 1 and 2, Varicella zoster virus, Enterovirus and C.neo was non detectable. CSF gram stain showed no organisms. Staining for acid fast bacilli and PCR for west nile virus and Lyme were negative. Autoimmune encephalitis panel came back positive for NMDA receptor antibody encephalitis for which he received IV steroids and IVIG. DISCUSSION:The characteristic picture of NMDA receptor antibody encephalitis can be divided into 3 phases: I with respiratory symptoms and mild fever, II with psychiatric manifestations and III with development of neurological symptoms.[5] Psychiatric symptoms consist of delusions, hallucinations, anxiety and mania while neurological manifestations includes movement disorder, autonomic instability, central hypoventilation and coma. [3,5] It is difficult to differentiate from primary psychiatric disorder if a patient presents with psychiatric symptoms. Early suspicion and diagnosis are key to start treatment in the form of immunotherapy or removal of the tumor. [6] CONCLUSIONS: The differential of NMDA receptor antibody encephalitis must be considered in young patients with neuropsychiatric symptoms as they are often misdiagnosed with psychiatric disorders, which impedes early treatment.The removal of the tumor and immunotherapy generally carry a good prognosis with complete recovery.