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We present two historic cases of severe encephalopathy associated with antithyroid antibodies. The first was published by Lord Brain of Eynsham, and the second was from our department’s archives. Although both cases are from archival sources, they continue to inform current clinical care. We briefly review the poorly defined entity, Hashimoto’s encephalopathy, and discuss diagnostic advances for autoimmune encephalopathy and for Creutzfeldt-Jakob disease. We advocate for giving a trial of corticosteroids to patients with ‘encephalopathy, not otherwise specified’ while awaiting antibody results or more definitive testing. Our case, initially diagnosed as having Creutzfeldt-Jakob disease, responded remarkably (with video evidence) to a trial of corticosteroids.

Background For many laboratories, autoimmune encephalopathy (AE) panels are send-out tests. These tests are expensive, and ordering patterns vary greatly. There is also a lack of consensus on which panel to order and poor understanding of the clinical utility of these panels. These challenges were presented to our newly formed, multidisciplinary, diagnostic stewardship committee (DSC). Through this collaboration, we developed an algorithm for ordering AE panels; combining diagnostic criteria with practice guidelines. Methods We analyzed test-ordering patterns in 2018 and calculated a true-positive rate based on clinical presentation and panel interpretation. An evidence-based approach was combined with input from the Department of Neurology to synthesize our algorithm. Efficacy of the algorithm (number of panels ordered, cost, and true positives) was assessed before and after implementation. Results In 2018, 77 AE-related panels were ordered, costing $137 510. The true-positive rate was 10%, although ordering multiple, similar panels for the same patient was common. Before implementing the algorithm (January 1–July 31, 2019), 55 panels were ordered, costing $105 120. The total true-positive rate was 3.6%. After implementation, 23 tests were ordered in a 5-month period, totaling $50 220. The true-positive rate was 13%. Conclusion With the DSC-directed mandate, we developed an algorithm for ordering AE panels. Comparison of pre- and postimplementation data showed a higher true-positive rate, indicating that our algorithm was able to successfully identify the at-risk population for AE disorders. This was met with a 43% decrease in the number of tests ordered, with total cost savings of $25 000 over 5 months.

Patients with Hashimoto encephalitis may present with seizures, stroke-like episodes, transient focal and global neurological deficits, and a variety of neuropsychiatric disturbances. The encephalopathy evolves with elevated anti-thyroid peroxidase antibodies, independent of hormonal thyroid function. A teenager experienced repeated concussions antedating onset of Hashimoto encephalopathy. Neuroradiological studies showed overlapping areas of altered brain metabolism and vascular perfusion in the hippocampus, deemed most vulnerable in autoimmune encephalopathy. Concussive brain injury may be a contributing factor in the development of encephalopathy due to its capacity to alter the blood-brain barrier.

Parry-Romberg syndrome (PRS) is a progressive facial hemiatrophy often associated with severe epilepsy. Although an immune-mediated vasculitic pathogenesis is widely assumed, no CNS-specific autoantibody has been described so far. A 2-year-old boy was admitted for a status epilepticus preceded by fever, restlessness, insomnia, and left facial rash. Cerebrospinal fluid was positive for glutamic acid decarboxylase (GAD)-antibodies. Brain MRI revealed FLAIR hyperintensities on left mediotemporal areas. He was successfully treated with intravenous methylprednisolone. One month later, seizures and facial rash reappeared and steroids were satisfactorily repeated. However, left hemifacial rash reappeared 5 months later, slowly followed by sclerotic skin lesions on frontal scalp and hemifacial sub-atrophy, leading to a diagnosis of PRS. Three years later, and despite chronic immunosuppression, new MRI lesions on left white matter are seen and left hemifacial atrophy has progressed. For the first time, we describe GAD autoantibodies in a PRS patient with epileptic encephalopathy. Epileptic syndromes with GAD autoantibodies are frequently described though with a questionable pathogenic significance. Given the clinical and MRI similarities of PRS with both Morphea and Rasmussen's encephalitis, we suggest that, in our patient, the initial facial skin vasculitis spread into CNS vessels through perforating arteries, inducing neuronal MHC-class I presentation of GAD epitopes, ultimately causing CD8-mediated neuronal cytotoxicity and the epileptic encephalopathy. GAD autoantibodies might represent the missing pathophysiological link between PRS and neuropsychiatric manifestations.

Isolated adrenocorticotropic hormone deficiency (IAD) is a cause of adrenal insufficiency (AI), which shows impaired secretion of adrenocorticotropic hormone (ACTH) with the preserved secretion of other anterior pituitary gland hormones. We herein report a case of IAD complicated by chronic thyroiditis presenting with neuropsychiatric symptoms without other signs indicative of AI that showed complete improvement of the cognitive function after the administration of corticosteroids. The clinical features of our case may be confused with autoimmune encephalopathies (AEs); however, IAD should be strictly differentiated from AEs, as it requires permanent hormone replacement without addition of immunosuppressive agents.

Objective The objective of this review is to determine the probability that catatonia in the hospital has a secondary cause (“medical catatonia”) and to calculate the relative proportions of these causes stratified by hospital setting. Methods PRISMA systematic review of PubMed. Results Eleven studies were included. Hospital-wide, 20% of catatonia was medical. In acute medical and surgical settings, medical catatonia comprised more than half of cases. At least 80% of older adults seen by consult psychiatry and critically ill patients had a medical cause. Two thirds of medical catatonia involved CNS-specific disease including encephalitis, neural injury, developmental disorders, structural brain pathology, or seizures. Conclusions Patients in acute medical and surgical settings with catatonia deserve a medical workup that prioritizes CNS etiologies.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory central nervous system syndrome, and encephalitis associated with anti-N-methyl-d-aspartate receptor (NMDAR) antibodies is an autoimmune encephalopathy. A patient with both diseases, separately or simultaneously, is rare as a clinical phenomenon, but cannot be ignored. We report the clinical characteristics and imaging features of a special case with anti-NMDAR encephalitis followed by NMOSD. We subsequently reviewed the English language literature about demyelinating disorders with anti-NMDAR encephalitis. Details of the 34 patients identified are summarized and compared. There may be a connection between anti-NMDAR encephalitis and NMOSD.

The understanding of the etio-pathogenesis of autoimmune encephalopathy syndromes has grown significantly in recent years. These are potentially reversible conditions, with variable clinical presentation and potential dramatic response to immunotherapy.In this article we review various diagnostic techniques and therapeutic options for management of autoimmune encephalopathy. We also review medication adverse effects and monitoring strategies. Expert commentary: Early diagnosis and immunomodulatory treatment remains the cornerstone of management, to halt the underlying neuro-inflammatory process and prevent permanent neuronal injury. The availability of serological testing and various imaging modalities has further improved detection of these immune-mediated neurological disorders. Understanding the mechanisms and potential adverse effects of immunomodulatory therapies will help physicians to choose the most favorable therapeutic strategy for each patient.

Encephalitis is an acute inflammatory condition of the brain caused by infective or autoimmune mechanisms. It typically involves headache, fever, confusion, seizures, and sensory or motor disturbance. Recently there have been increased understandings of the role of neuronal cell antibodies in presentations of encephalitis that have psychiatric features only.